26 research outputs found
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Coupled versus uncoupled hindcast simulations of the Madden-Julian oscillation in the Year of Tropical Convection
This study investigates the impact of a full interactive ocean on daily initialised 15 day hindcasts of the Madden-Julian oscillation (MJO), measured against a Met Office Unified Model (MetUM) atmosphere control simulation (AGCM) during a 3 month period of the Year of Tropical Convection (YOTC). Results indicated that the coupled configuration (CGCM) extends MJO predictability over that of the AGCM, by up to 3-5 days. Propagation is improved in the CGCM, which we partly attribute to a more realistic phase relationship between sea surface temperature (SST) and convection. In addition, the CGCM demonstrates skill in representing downwelling oceanic Kelvin and Rossby waves which warm SSTs along their trajectory, with the potential to feed back on the atmosphere. These results imply that an ocean model capable of simulating internal ocean waves may be required to capture the full effect of air-sea coupling for the MJO
Airborne Infection with Bacillus anthracis—from Mills to Mail
The lack of identified exposures in 2 of the 11 cases of bioterrorism-related inhalation anthrax in 2001 raised uncertainty about the infectious dose and transmission of Bacillus anthracis. We used the Wells-Riley mathematical model of airborne infection to estimate 1) the exposure concentrations in postal facilities where cases of inhalation anthrax occurred and 2) the risk for infection in various hypothetical scenarios of exposure to B. anthracis aerosolized from contaminated mail in residential settings. These models suggest that a small number of cases of inhalation anthrax can be expected when large numbers of persons are exposed to low concentrations of B. anthracis. The risk for inhalation anthrax is determined not only by bacillary virulence factors but also by infectious aerosol production and removal rates and by host factors
Implementing Evidence-Based Alcohol Interventions in a Resource-Limited Setting: Novel Delivery Strategies in Tomsk, Russia
Effective implementation of evidence-based interventions in “real-world” settings can be challenging. Interventions based on externally valid trial findings can be even more difficult to apply in resource-limited settings, given marked differences—in provider experience, patient population, and health systems—between those settings and the typical clinical trial environment. Under the auspices of the Integrated Management of Physician-Delivered Alcohol Care for Tuberculosis Patients (IMPACT) study, a randomized, controlled effectiveness trial, and as an integrated component of tuberculosis treatment in Tomsk, Russia, we adapted two proven alcohol interventions to the delivery of care to 200 patients with alcohol use disorders. Tuberculosis providers performed screening for alcohol use disorders and also delivered naltrexone (with medical management) or a brief counseling intervention either independently or in combination as a seamless part of routine care. We report the innovations and challenges to intervention design, training, and delivery of both pharmacologic and behavioral alcohol interventions within programmatic tuberculosis treatment services. We also discuss the implications of these lessons learned within the context of meeting the challenge of providing evidence-based care in resource-limited settings. (Harv Rev Psychiatry 2012;20:58–67.
Redesigning care for older people to preserve physical and mental capacity: WHO guidelines on community-level interventions in integrated care.
Islene Araujo de Carvalho and coauthors discuss the WHO guidelines on integrated care for older people
Double seismic zone of the Nazca plate in northern Chile: High‐resolution velocity structure, petrological implications, and thermomechanical modeling
This paper presents an interdisciplinary study of the northern Chile double seismic zone. First, a high‐resolution velocity structure of the subducting Nazca plate has been obtained by the tomoDD double‐difference tomography method. The double seismic zone (DSZ) is observed between 80 and 140 km depth, and the two seismic planes is 20 km apart. Then, the chemical and petrologic characteristics of the oceanic lithosphere associated with this DSZ are deduced by using current thermal‐petrological‐seismological models and are compared to pressure‐temperature conditions provided by a numerical thermomechanical model. Our results agree with the common hypothesis that seismicity in both upper and lower planes is related to fluid releases associated with metamorphic dehydration reactions. In the seismic upper plane located within the upper crust, these reactions would affect material of basaltic (MORB) composition and document different metamorphic reactions occurring within high‐P (>2.4 GPa) and low‐T (130 km), lawsonite‐amphibole eclogite conditions. The lower plane lying in the oceanic mantle can be associated with serpentinite dehydration reactions. The Vp and Vs characteristics of the region in between both planes are consistent with a partially (∼25–30 vol % antigorite, ∼0–10% vol % brucite, and ∼4–10 vol % chlorite) hydrated harzburgitic material. Discrepancies persist that we attribute to complexities inherent to heterogeneous structural compositions. While various geophysical indicators evidence particularly cold conditions in both the descending Nazca plate and the continental fore arc, thermomechanical models indicate that both seismic planes delimit the inner slab compressional zone around the 400°C (±50°C) isotherm. Lower plane earthquakes are predicted to occur in the slab's flexural neutral plane, where fluids released from surrounding metamorphic reactions could accumulate and trigger seismicity. Fluids migrating upward from the tensile zone below could be blocked in their ascension by the compressive zone above this plane, thus producing a sheeted layer of free fluids, or a serpentinized layer. Therefore earthquakes may present either downdip compression and downdip tensile characteristics. Numerical tests indicate that the slab's thermal structure is not the only factor that controls the occurrence of inner slab compression. (1) A weak ductile subduction channel and (2) a cold mantle fore arc both favor inner slab compression by facilitating transmission of compressional stresses from the continental lithosphere into the slab. (3) Decreasing the radius of curvature of the slab broadens the depth of inner slab compression, whereas (4) decreasing upper plate convergence diminishes its intensity. All these factors indicate that if DSZs indeed contour inner slab compression, they cannot be linked only to slab unbending, but also to the transmission of high compressional stresses from the upper plate into the slab