CHEM2D-OPP: A new linearized gas-phase ozone photochemistry parameterization for high-altitude NWP and climate models

The new CHEM2D-Ozone Photochemistry Parameterization (CHEM2D-OPP) for high-altitude numerical weather prediction (NWP) systems and climate models specifies the net ozone photochemical tendency and its sensitivity to changes in ozone mixing ratio, temperature and overhead ozone column based on calculations from the CHEM2D interactive middle atmospheric photochemical transport model. We evaluate CHEM2D-OPP performance using both short-term (6-day) and long-term (1-year) stratospheric ozone simulations with the prototype high-altitude NOGAPS-ALPHA forecast model. An inter-comparison of NOGAPS-ALPHA 6-day ozone hindcasts for 7 February 2005 with ozone photochemistry parameterizations currently used in operational NWP systems shows that CHEM2D-OPP yields the best overall agreement with both individual Aura Microwave Limb Sounder ozone profile measurements and independent hemispheric (10°–90° N) ozone analysis fields. A 1-year free-running NOGAPS-ALPHA simulation using CHEM2D-OPP produces a realistic seasonal cycle in zonal mean ozone throughout the stratosphere. We find that the combination of a model cold temperature bias at high latitudes in winter and a warm bias in the CHEM2D-OPP temperature climatology can degrade the performance of the linearized ozone photochemistry parameterization over seasonal time scales despite the fact that the parameterized temperature dependence is weak in these regions

Influence of mountain waves and NAT nucleation mechanisms on Polar Stratospheric Cloud formation at local and synoptic scales during the 1999?2000 Arctic winter

International audienceA scheme for introducing mountain wave-induced temperature pertubations in a microphysical PSC model has been developed. A data set of temperature fluctuations attributable to mountain waves as computed by the Mountain Wave Forecast Model (MWFM-2) has been used for the study. The PSC model has variable microphysics, enabling different nucleation mechanisms for nitric acid trihydrate, NAT, to be employed. In particular, the difference between the formation of NAT and ice particles in a scenario where NAT formation is not dependent on preexisting ice particles, allowing NAT to form at temperatures above the ice frost point, Tice, and a scenario, where NAT nucleation is dependent on preexisting ice particles, is examined. The performance of the microphysical model in the different microphysical scenarios and a number of temperature scenarios with and without the influence of mountain waves is tested through comparisons with lidar measurements of PSCs made from the NASA DC-8 on 23 and 25 January during the SOLVE/THESEO 2000 campaign in the 1999?2000 winter and the effect of mountain waves on local PSC production is evaluated in the different microphysical scenarios. Mountain wave-induced temperature fluctuations are introduced in vortex-covering model runs, extending the full 1999?2000 winter season, and the effect of mountain waves on large-scale PSC production is estimated in the different microphysical scenarios

Potential application of hydrogen in traumatic and surgical brain injury, stroke and neonatal hypoxia-ischemia

This article summarized findings of current preclinical studies that implemented hydrogen administration, either in the gas or liquid form, as treatment application for neurological disorders including traumatic brain injury (TBI), surgically induced brain injury (SBI), stroke, and neonatal hypoxic-ischemic brain insult (HI). Most reviewed studies demonstrated neuroprotective effects of hydrogen administration. Even though anti-oxidative potentials have been reported in several studies, further neuroprotective mechanisms of hydrogen therapy remain to be elucidated. Hydrogen may serve as an adjunct treatment for neurological disorders

Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

International audienceThe forecast model and three-dimensional variational data assimilation components of the Navy Operational Global Atmospheric Prediction System (NOGAPS) have each been extended into the upper stratosphere and mesosphere to form an Advanced Level Physics High Altitude (ALPHA) version of NOGAPS extending to ~100 km. This NOGAPS-ALPHA NWP prototype is used to assimilate stratospheric and mesospheric temperature data from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Radiometry (SABER) instruments. A 60-day analysis period in January and February, 2006, was chosen that includes a well documented stratospheric sudden warming. SABER temperatures indicate that the SSW caused the polar winter stratopause at ~40 km to disappear, then reform at ~80 km altitude and slowly descend during February. The NOGAPS-ALPHA analysis reproduces this observed stratospheric and mesospheric temperature structure, as well as realistic evolution of zonal winds, residual velocities, and Eliassen-Palm fluxes that aid interpretation of the vertically deep circulation and eddy flux anomalies that developed in response to this wave-breaking event. The observation minus forecast (O-F) standard deviations for MLS and SABER are ~2 K in the mid-stratosphere and increase monotonically to about 6 K in the upper mesosphere. Increasing O-F standard deviations in the mesosphere are expected due to increasing instrument error and increasing geophysical variance at small spatial scales in the forecast model. In the mid/high latitude winter regions, 10-day forecast skill is improved throughout the upper stratosphere and mesosphere when the model is initialized using the high-altitude analysis based on assimilation of both SABER and MLS data

Synthesis and Characterization of Ruthenium and Rhenium Nucleosides

We report the synthesis and characterization of new ruthenium and rhenium nucleosides [Ru(tolyl-acac)_2(IMPy)-T] (tolyl-acac = di(p-methylbenzonatemethane), IMPy = 2‘-iminomethylpyridine, T = thymidine) (5) and [Re(CO)_3(IMPy)-T]Cl (9), respectively. Structural analysis of 9 shows that the incorporation of this metal complex causes minimal perturbation to the sugar backbone and the nucleobase. Eletrochemical (5, E_(1/2) = 0.265 V vs NHE; 9, E_(1/2) = 1.67 V vs NHE), absorption (5, λ_(max) = 600, 486 nm; 9, λ_(max) = 388 nm), and emission (9, λ_(max) = 770 nm, π = 17 ns) data indicate that 5 and 9 are suitable probes for DNA-mediated ground-state electron-transfer studies. The separation and characterization of diastereoisomers of 5 and bipyridyl-based ruthenium nucleoside [Ru(bpy)_2(IMPy)-T]^(2+) (7) are reported

Contemporary nursing graduates\u27 transition to practice: A critical review of transition models

AIM AND OBJECTIVE: To critically review contemporary transition theories to determine how they apply to the newly qualified graduate registered nurse programmes. BACKGROUND: Graduate nurse transition to employment is the time of significant change which has resulted in high attrition rates. Graduates are often challenged by their expectation of nursing practice and the reality of the role. The transition from hospital-based training to university-based training has resulted in the need for primary employment to commence with graduate/orientation/internship programmes to help support new graduates transition into clinical practice. One transition model, Duchscher\u27s stages of transition theory, utilised three former theories to develop a final model. DESIGN: A narrative critical literature review. METHOD: The theories selected for the review were Kramer\u27s reality shock theory, Benner\u27s novice to expert theory, Bridges transition theory and Duchscher\u27s stages of transition theory. CONCLUSION: Duchscher\u27s stages of transition theory reflects the experiences of registered nursing transition into the workforce directly from university. The application of the theory is effective to guide understanding of the current challenges that new graduate nurse\u27s experience today. There is a need for new graduates to complete their university degree as advanced beginners in order to decrease the experience of transition shock and keep pace with rapidly changing demands of the clinical environment. This may be achieved by increasing ward-based simulation in university education. A theoretical framework can provide a deep understanding of the various stages and processes of transition and enable development of successful programmes. RELEVANCE TO CLINICAL PRACTICE: Both universities and hospitals need to adapt their current practice to align with the needs of new graduates due to large student numbers and ongoing systematic advancements to decrease the attrition rate

AMP second national workshop. Asthma Management Program

Powerpoint presentation presented at the Asthma Management Program: Second National Workshop, Stamford Plaza Sydney Airport Hote

NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign

This paper presents three-dimensional prognostic O₃ simulations with parameterized gas-phase photochemistry from the new NOGAPS-ALPHA middle atmosphere forecast model. We compare 5-day NOGAPS-ALPHA hindcasts of stratospheric O₃ with satellite and DC-8 aircraft measurements for two cases during the SOLVE II campaign: (1) the cold, isolated vortex during 11-16 January 2003; and (2) the rapidly developing stratospheric warming of 17-22 January 2003. In the first case we test three different photochemistry parameterizations. NOGAPS-ALPHA O₃ simulations using the NRL-CHEM2D parameterization give the best agreement with SAGE III and POAM III profile measurements. 5-day NOGAPS-ALPHA hindcasts of polar O₃ initialized with the NASA GEOS4 analyses produce better agreement with observations than do the operational ECMWF O₃ forecasts of case 1. For case 2, both NOGAPS-ALPHA and ECMWF 114-h forecasts of the split vortex structure in lower stratospheric O₃ on 21 January 2003 show comparable skill. Updated ECMWF O₃ forecasts of this event at hour 42 display marked improvement from the 114-h forecast; corresponding updated 42-hour NOGAPS-ALPHA prognostic O₃ fields initialized with the GEOS4 analyses do not improve significantly. When NOGAPS-ALPHA prognostic O₃ is initialized with the higher resolution ECMWF O₃ analyses, the NOGAPS-ALPHA 42-hour lower stratospheric O₃ fields closely match the operational 42-hour ECMWF O₃ forecast of the 21 January event. We find that stratospheric O₃ forecasts at high latitudes in winter can depend on both model initial conditions and the treatment of photochemistry over periods of 1-5 days. Overall, these results show that the new O₃ initialization, photochemistry parameterization, and spectral transport in the NOGAPS-ALPHA NWP model can provide reliable short-range stratospheric O₃ forecasts during Arctic winter

Primary demyelination induced by exposure to tellurium alters Schwann cell gene expression: a model for intracellular targeting of NGF receptor

Exposure of developing rats to tellurium results in a highly synchronous segmental demyelination of peripheral nerves with sparing of axons; this demyelination is followed closely by a period of rapid remyelination. Demyelination occurs subsequent to a tellurium-induced block in the synthesis of cholesterol, the major myelin lipid. We utilized the techniques of Northern blotting, in situ hybridization, and immunocytochemistry to examine temporal alterations in Schwann cell gene expression related to demyelination and remyelination. Tellurium- induced demyelination is associated with downregulation of myelin protein expression and a corresponding upregulation of NGF receptor (NGF-R) and glial fibrillary acidic protein (GFAP) expression. Steady- state mRNA levels (expressed on a “per nerve” basis) for P0, the major myelin protein, were decreased by about 50% after 5 d of tellurium exposure, while levels of mRNA for NGF-R and GFAP were markedly increased (about 15-fold). In situ hybridization of teased fibers suggested that the increase in steady-state mRNA levels for NGF-R was primarily associated with demyelinated internodes and not with adjacent unaffected internodes. Although P0 message was almost totally absent from demyelinating internodes, it was also reduced in normal-appearing internodes as well. This suggests that limiting the supply of a required membrane component (cholesterol) may lead to partial downregulation of myelin gene expression in all myelinating Schwann cells. In partially demyelinated internodes, NGF-R and GFAP immunofluorescence appeared largely confined to the demyelinated regions. This suggests specific targeting of these proteins to local areas of the Schwann cell where there is myelin loss. These results demonstrate that demyelination is associated with reversion of the affected Schwann cells to a precursor cell phenotype. Because axons remain intact, our results suggest that these changes in Schwann cell gene expression do not require input from a degenerating axon, but instead may depend on whether concerted synthesis of myelin is occurring