The Famine Early Warning System Network (FEWS NET) provides monitoring and early warning support to decision makers responsible for responding to famine and food insecurity. FEWS NET transforms satellite remote sensing data into rainfall and vegetation information that can be used by these decision makers. The National Aeronautics and Space Administration has recently funded activities to enhance remote sensing inputs to FEWS NET. To elicit Earth observation requirements, a professional review questionnaire was disseminated to FEWS NET expert end-users; it focused upon operational requirements to determine additional useful remote sensing data and, subsequently, to assess whether such data would be beneficial as FEWS NET biophysical supplementary inputs. The review was completed by over 40 experts from around the world. Reviewers were asked to evaluate the relative importance of environmental variables and spatio-temporal requirements for Earth science data products, in particular for rainfall and vegetation products. The results showed that spatio-temporal resolution requirements are complex and need to vary according to place, time, and hazard; that high resolution remote sensing products continue to be in demand; and that rainfall and vegetation products are valued as data that provide actionable food security information.
Nasal one-third sized fragments were created from fully differentiated larval Xenopus eyes (stage 47). At various times post-surgery, animals were injected with tritiated thymidine. All animals were fixed 1 day post-injection. Animals injected 1 day post-surgery showed limited healing and thymidine labeling in the retina. In animals injected 1 week post-surgery, heavy thymidine label was localized in the ventrotemporal retina in a "thickened" neuroepithelium internal to the extending pigmented retinal epithelium. In contrast, the dorsal retina showed no apparent extra labeling, but rather resembled normal ciliary margin. In animals injected 1 month post-surgery, the eye fragment regained normal size and retinal layering, and the label was restricted to the ciliary margin. Regenerative growth associated with healing appeared to have been completed by this time. This extra cell division that occurs during the 1st month post-surgery may underlie novel axonal targeting properties shown by nasal one-third sized fragments. For example, these findings are consistent with the idea that pattern duplication of the visuotectal projection in nasal one-third sized eye fragments occurs via intercalary cell division during healing and regeneration.
We examined the relationship between early healing modes and extra cell division (via tritiated thymidine incorporation) during embryonic retinal regeneration. Nasal (N) and dorsal (D) one-third sized eye fragments were surgically created in stage 32 Xenopus laevis embryos. Embryos were injected with tritiated thymidine two days postsurgery (stage 43), and then fixed and processed for autoradiography one day postinjection (stage 46). Histological analysis revealed that all nasal one-third sized fragments showed cell displacement in healing regions. These displaced cells were located in the ventral retinal region and showed heavy thymidine label incorporation. Alternatively, most dorsal one-third sized fragments showed little cell displacement during healing; in addition, no extra thymidine incorporation was evident. A minority of dorsal one-third sized fragments showed cell displacement during healing, and also showed significant local label ventrally through all regions of the eye. Therefore, in both dorsal and nasal one-third sized retinal fragments, when cell displacements were observed during early healing, associated mitosis was apparent in ventral retinal regions. Furthermore, by 60 hours postsurgery, all eyes which showed cell displacements during healing were greater in volume than those eyes which showed little cell displacement. Increases in volume appear to be derived from a combination of both cells migrating in from underlying optic stalk tissue and from related extra cell division during healing. These data further support a model which predicts that specific healing interactions which involve cell displacement during embryonic retinal regeneration and subsequent intercalary growth underlie visuotectal pattern formation.
NASA Platform for Autonomous Systems (NPAS) is a disruptive software platform and processes being developed by SSC Autonomous Systems Laboratory (ASL). Autonomous operations are critical for the success, safety and crew survival of NASA deep space missions beyond low Earth orbit, including Lunar Orbital Platform-Gateway, and for the future of cost-effective ground mission operations. NPAS represents the embodiment of an innovative implementation for "thinking" autonomy in contrast to brute-force autonomy. It also uniquely addresses the require ments and integrates five primary functionalities for autonomous operations including: (1) Integrated System Health Management (ISHM), (2) autonomy, guided by health and system concepts of operations; (3) knowledge models of applications; (4) infrastructure to create, schedule, and execute mission plans; and (5) infrastructure to integrate distributed autonomous applications across networks.
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