Fluxes of momentum and moist enthalpy across the air-sea interface are believed to be one of the most important factors in determining tropical cyclone intensity. Because these surface fluxes cannot ...be directly resolved by numerical weather prediction models, their impacts on tropical cyclones must be accounted for through subgrid-scale parameterizations. There are several air-sea surface flux parameterization schemes available in the Weather Research and Forecasting (WRF) Model; these schemes differ from one another in their formulations of the wind speed-dependent exchange coefficients of momentum, sensible heat, and moisture (latent heat). The effects of surface fluxes on the intensity and structure of tropical cyclones are examined through convection-permitting WRF simulations of Hurricane Katrina (2005). It is found that the intensity (and, to a lesser extent, structure) of the simulated storms is sensitive to the choice of surface flux parameterization scheme. In agreement with recent studies, the drag coefficient C sub(D) is found to affect the pressure-wind relationship (between minimum sea level pressure and maximum 10-m wind speed) and to change the radius of maximum near-surface winds of the tropical cyclone. Fluxes of sensible and latent heat (i.e., moist enthalpy) affect intensity but do not significantly change the pressure-wind relationship. Additionally, when low-level winds are strong, the contribution of dissipative heating to calculations of sensible heat flux is not negligible. Expanding the sensitivity tests to several dozen cases from the 2008 to 2011 Atlantic hurricane seasons demonstrates the robustness of these findings.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
2.
THE SUBSEASONAL EXPERIMENT (SubX) Pegion, Kathy; Kirtman, Ben P.; Becker, Emily ...
Bulletin of the American Meteorological Society,
10/2019, Volume:
100, Issue:
10
Journal Article
Peer reviewed
Open access
The Subseasonal Experiment (SubX) is a multimodel subseasonal prediction experiment designed around operational requirements with the goal of improving subseasonal forecasts. Seven global models have ...produced 17 years of retrospective (re)forecasts and more than a year of weekly real-time forecasts. The reforecasts and forecasts are archived at the Data Library of the International Research Institute for Climate and Society, Columbia University, providing a comprehensive database for research on subseasonal to seasonal predictability and predictions. The SubX models show skill for temperature and precipitation 3 weeks ahead of time in specific regions. The SubX multimodel ensemble mean is more skillful than any individual model overall. Skill in simulating the Madden–Julian oscillation (MJO) and the North Atlantic Oscillation (NAO), two sources of subseasonal predictability, is also evaluated, with skillful predictions of the MJO 4 weeks in advance and of the NAO 2 weeks in advance. SubX is also able to make useful contributions to operational forecast guidance at the Climate Prediction Center. Additionally, SubX provides information on the potential for extreme precipitation associated with tropical cyclones, which can help emergency management and aid organizations to plan for disasters.
Full text
Available for:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Factors that affect the quality of clinical decisions of multidisciplinary cancer teams (MDTs) are not well understood. We reviewed and synthesised the evidence on clinical, social and ...technological factors that affect the quality of MDT clinical decision-making.
Methods
Electronic databases were searched in May 2009. Eligible studies reported original data, quantitative or qualitative. Data were extracted and tabulated by two blinded reviewers, and study quality formally evaluated.
Results
Thirty-seven studies were included. Study quality was low to medium. Studies assessed quality of care decisions via the effect of MDTs on care management. MDTs changed cancer management by individual physicians in 2–52% of cases. Failure to reach a decision at MDT discussion was found in 27–52% of cases. Decisions could not be implemented in 1–16% of cases. Team decisions are made by physicians, using clinical information. Nursing personnel do not have an active role, and patient preferences are not discussed. Time pressure, excessive caseload, low attendance, poor teamworking and lack of leadership lead to lack of information and deterioration of decision-making. Telemedicine is increasingly used in developed countries, with no detriment to quality of MDT decisions.
Conclusions
Team/social factors affect management decisions by cancer MDTs. Inclusion of time to prepare for MDTs into team-members’ job plans, making team and leadership skills training available to team-members, and systematic input from nursing personnel would address some of the current shortcomings. These improvements ought to be considered at national policy level, with the ultimate aim of improving cancer care.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
To demonstrate the feasibility of online adaptive magnetic resonance (MR) image guided radiation therapy (MR-IGRT) through reporting of our initial clinical experience and workflow considerations.
...The first clinically deployed online adaptive MR-IGRT system consisted of a split 0.35T MR scanner straddling a ring gantry with 3 multileaf collimator-equipped (60)Co heads. The unit is supported by a Monte Carlo-based treatment planning system that allows real-time adaptive planning with the patient on the table. All patients undergo computed tomography and MR imaging (MRI) simulation for initial treatment planning. A volumetric MRI scan is acquired for each patient at the daily treatment setup. Deformable registration is performed using the planning computed tomography data set, which allows for the transfer of the initial contours and the electron density map to the daily MRI scan. The deformed electron density map is then used to recalculate the original plan on the daily MRI scan for physician evaluation. Recontouring and plan reoptimization are performed when required, and patient-specific quality assurance (QA) is performed using an independent in-house software system.
The first online adaptive MR-IGRT treatments consisted of 5 patients with abdominopelvic malignancies. The clinical setting included neoadjuvant colorectal (n=3), unresectable gastric (n=1), and unresectable pheochromocytoma (n=1). Recontouring and reoptimization were deemed necessary for 3 of 5 patients, and the initial plan was deemed sufficient for 2 of the 5 patients. The reasons for plan adaptation included tumor progression or regression and a change in small bowel anatomy. In a subsequently expanded cohort of 170 fractions (20 patients), 52 fractions (30.6%) were reoptimized online, and 92 fractions (54.1%) were treated with an online-adapted or previously adapted plan. The median time for recontouring, reoptimization, and QA was 26 minutes.
Online adaptive MR-IGRT has been successfully implemented with planning and QA workflow suitable for routine clinical application. Clinical trials are in development to formally evaluate adaptive treatments for a variety of disease sites.
Full text
Available for:
GEOZS, IJS, NUK, OILJ, UL, UM, UPUK
Tropical cyclones (TCs) are strongly influenced by fluxes of momentum and moist enthalpy across the airsea interface. These fluxes cannot be resolved explicitly by current-generation numerical ...weather prediction models, and therefore must be accounted for via empirical parameterizations of surface exchange coefficients (C sub(D) for momentum and C sub(k) for moist enthalpy). The resultant model uncertainty is examined through hundreds of convection-permitting Weather Research and Forecasting Model (WRF) simulations of Hurricane Katrina (2005) by varying four key parameters found in commonly used parameterizations of the exchange coefficient formulas. Two of these parameters effectively act as multiplicative factors for the exchange coefficients over all wind speeds (one each for C sub(D) and C sub(k)); the other two parameters control the behavior of C sub(D) at very high wind speeds (i.e., above 33 m s super(-1)). It is found that both the intensity and the structure of TCs are highly dependent upon the two multiplicative parameters. The multiplicative parameter for C sub(D) has a considerably larger impact than the one for C sub(k) on the relationship between maximum 10-m wind speed and minimum sea level pressure: C sub(D) alters TC structure, with higher values shifting the radius of maximum winds inward and strengthening the low-level inflow; C sub(k) only affects structure by uniformly strengthening/weakening the primary and secondary circulations. The TC exhibits the greatest sensitivities to the two multiplicative parameters after a few hours of model integration, suggesting that these parameters could be estimated by assimilating near-surface observations. The other two parameters are likely more difficult to estimate because the TC is only marginally sensitive to them in small areas of high wind speed.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In many health care systems globally, cancer care is driven by multidisciplinary cancer teams (MDTs). A large number of studies in the past few years and across different literature have been ...performed to better understand how these teams work and how they manage patient care. The aim of our literature review is to synthesize current scientific and clinical understanding on cancer MDTs and their organization; this, in turn, should provide an up-to-date summary of the current knowledge that those planning or leading cancer services can use as a guide for service implementation or improvement. We describe the characteristics of an effective MDT and factors that influence how these teams work. A range of factors pertaining to teamwork, availability of patient information, leadership, team and meeting management, and workload can affect how well MDTs are implemented within patient care. We also review how to assess and improve these teams. We present a range of instruments designed to be used with cancer MDTs - including observational tools, self-assessments, and checklists. We conclude with a practical outline of what appears to be the best practices to implement (Dos) and practices to avoid (Don'ts) when setting up MDT-driven cancer care.
Two decades since their inception, multidisciplinary teams (MDTs) are widely regarded as the ‘gold standard’ of cancer care delivery. Benefits of MDT working include improved patient outcomes, ...adherence to guidelines, and even economic benefits. Benefits to MDT members have also been demonstrated. An increasing body of evidence supports the use of MDTs and provides guidance on best practise. The system of MDTs in cancer care has come under increasing pressure of late, due to the increasing incidence of cancer, the popularity of MDT working, and financial pressures. This pressure has resulted in recommendations by national bodies to implement streamlining to reduce workload and improve efficiency. In the present review we examine the historical evidence for MDT working, and the scientific developments that dictate best practise. We also explore how streamlining can be safely and effectively undertaken. Finally, we discuss the future of MDT working including the integration of artificial intelligence and decision support systems and propose a new model for improving patient centredness.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Monthlong hindcasts of the Madden-Julian oscillation (MJO) from the atmospheric Flow-following Icosahedral Model coupled with an icosahedral-grid version of the Hybrid Coordinate Ocean Model ...(FIM-iHYCOM), and from the coupled Climate Forecast System, version 2 (CFSv2), are evaluated over the 12-yr period 1999-2010. Two sets of FIM-iHYCOM hindcasts are run to test the impact of using Grell-Freitas (FIM-CGF) versus simplified Arakawa-Schubert (FIM-SAS) deep convection parameterizations. Each hindcast set consists of four time-lagged ensemble members initialized weekly every 6 h from 1200 UTC Tuesday to 0600 UTC Wednesday. The ensemble means of FIM-CGF, FIM-SAS, and CFSv2 produce skillful forecasts of a variant of the Real-time Multivariate MJO (RMM) index out to 19, 17, and 17 days, respectively; this is consistent with FIM-CGF having the lowest root-mean-square errors (RMSEs) for zonal winds at both 850 and 200 hPa. FIM-CGF and CFSv2 exhibit similar RMSEs in RMM, and their
ensemble mean extends skillful RMM prediction out to 21 days. Conversely, adding FIM-SAS-with much higher RMSEs-to CFSv2 (as a multimodel ensemble) or FIM-CGF (as a
ensemble) yields either little benefit, or even a degradation, compared to the better single-model ensemble mean. This suggests that multiphysics/multimodel ensemble mean forecasts may only add value when the individual models possess similar skill and error. An atmosphere-only version of FIM-CGF loses skill after 11 days, highlighting the importance of ocean coupling. Further examination reveals some sensitivity in skill and error metrics to the choice of MJO index.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
Subseasonal forecast skill of the global hydrostatic atmospheric Flow-Following Icosahedral Model (FIM) coupled to an icosahedral-grid version of the Hybrid Coordinate Ocean Model (iHYCOM) ...is evaluated through 32-day predictions initialized weekly using a four-member time-lagged ensemble over the 16-yr period 1999–2014. Systematic biases in forecasts by the coupled system, referred to as FIM–iHYCOM, are described in a companion paper (Part I). This present study (Part II) assesses probabilistic and deterministic model skill for predictions of surface temperature, precipitation, and 500-hPa geopotential height in different seasons at different lead times ranging from 1 to 4 weeks. The coupled model appears to have reasonable agreement with reanalysis in terms of simulated weekly variability in sea surface temperatures, except in extratropical regions because the ocean model cannot explicitly resolve eddies there. This study also describes the ability of the model to simulate midlatitude tropospheric blocking frequency, Madden–Julian oscillation patterns, and sudden stratospheric warming events—all of which have been shown to be relevant on subseasonal time scales. The metrics used here indicate that the subseasonal forecast skill of the model is comparable to that of several operational models, including the National Oceanic and Atmospheric Administration’s (NOAA’s) operational Climate Forecast System version 2 and the European Centre for Medium-Range Weather Forecasts model. Therefore, FIM–iHYCOM—as a participant in NOAA’s Subseasonal Experiment—is expected to add value to multimodel ensemble forecasts produced through this effort.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Background Due to its complexity, cancer care is increasingly being delivered by multidisciplinary tumor boards (MTBs). Few studies have investigated how best to organize and run MTBs to optimize ...clinical decision making. We developed and evaluated a multicomponent intervention designed to improve the MTB's ability to reach treatment decisions. Study Design We conducted a prospective longitudinal study during 16 months that evaluated MTB decision making for urological cancer patients at a university hospital in London, UK. After a baseline period, MTB improvement interventions (eg, MTBs checklist, MTB team training, and written guidance) were delivered sequentially. Outcomes measures were the MTB's ability to reach a decision, the quality of information presentation, and the quality of teamwork (as assessed by trained assessors using a previously validated observational assessment tool). The efficacy of the intervention was evaluated using multivariate analyses. Results There were 1,421 patients studied between December 2009 and April 2, 2011. All outcomes improved considerably between baseline and intervention implementation: the MTB's ability to reach a decision rose from 82.2% to 92.7%, quality of information presentation rose from 29.6% to 38.3%, and quality of teamwork rose from 37.8% to 43.0%. The MTB's ability to reach a treatment decision was related to the quality of available information ( r = 0.298; p < 0.05) and quality of teamwork within the MTB ( r = 0.348; p < 0.05). The most common barriers to reaching clinical decisions were inadequate radiologic information (n = 77), inadequate pathologic information (n = 51), and inappropriate patient referrals (n = 21). Conclusions Multidisciplinary tumor board−delivered treatment is becoming the standard for cancer care worldwide. Our intervention is efficacious and applicable to MTBs and can improve decision making and expedite cancer care.
PDF
