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[1] Variations in the Martian water and CO 2 cycles with changes in orbital and rotational parameters are examined using the Geophysical Fluid Dynamics Laboratory Mars General Circulation Model. The model allows for arbitrary specification of obliquity, eccentricity, and argument of perihelion as well as the position and thickness of surface ice. Exchange(More)
The Notch family of transmembrane receptor proteins mediate developmental cell-fate decisions, and mutations in mammalian Notch genes have been implicated in leukaemia, breast cancer, stroke and dementia. During wing development in Drosophila, the Notch receptor is activated along the border between dorsal and ventral cells, leading to the specification of(More)
The configuration and performance of a new global atmosphere and land model for climate research developed at the Geophysical Fluid Dynamics Laboratory (GFDL) is presented. The atmosphere model, known as AM2, includes a new gridpoint dynamical core, a prognostic cloud scheme, and a multi-species aerosol climatology, and components from previous models used(More)
Using corridors for conservation is increasing despite a lack of consensus on their efficacy. Specifically, whether corridors increase movement of plants and animals between habitat fragments has been addressed on a case-by-case basis with mixed results. Because of the growing number of well-designed experiments that have addressed this question, we(More)
Notch receptors function in highly conserved intercellular signalling pathways that direct cell-fate decisions, proliferation and apoptosis in metazoans. Fringe proteins can positively and negatively modulate the ability of Notch ligands to activate the Notch receptor. Here we establish the biochemical mechanism of Fringe action. Drosophila and mammalian(More)
[1] We describe the first use of a general circulation model to study the Martian water cycle. Water is treated as a passive tracer, except for ice-albedo coupling. The model is used to assess which mechanisms and water reservoirs are critical to the seasonal evolution of water and specifically the attainment of an interannually repeatable steady state. The(More)
To investigate the effects of the middle atmosphere on climate, the World Climate Research Programme is supporting the project " Stratospheric Processes and their Role in Climate " (SPARC). A central theme of SPARC, to examine model simulations of the coupled troposphere–middle atmosphere system, is being performed through the initiative called GRIPS(More)
Large seasonal and hemispheric asymmetries in the martian climate system are generally ascribed to variations in solar heating associated with orbital eccentricity. As the orbital elements slowly change (over a period of >104 years), characteristics of the climate such as dustiness and the vigour of atmospheric circulation are thought to vary, as should(More)
[1] We report new results on the structure and dynamics of the tropical atmosphere of Mars derived from a combination of radio occultation measurements by Mars Global Surveyor and simulations by a Mars general circulation model (MGCM). Radio occultation experiments sounded the equatorial atmosphere at latitudes of 36°N to 30°S during midsummer of the(More)
[1] Analysis of temperature retrievals from Mars Global Surveyor Thermal Emission Spectrometer data has revealed the presence of regular, eastward propagating waves in the Northern Hemisphere. A large amplitude, zonal wave 1 with a long ($20 sol) period is particularly prominent during early winter (L s = 220– 270°). After L s = 270°, a weaker and more(More)