Development of an Accelerated Test Design for Predicting the Service Life of the Solar Array at Mead, Nebraska

Potential long-term degradation modes for the two types of modules in the Mead array were determined and judgments were made as to those environmental stresses and combinations of stresses which accelerate the degradation of the power output. Hierarchical trees representing the severity of effects of stresses (test conditions) on eleven individual degradation modes were constructed and were pruned of tests judged to be nonessential. Composites of those trees were developed so that there is now one pruned tree covering eight degradation modes, another covering two degradation modes, and a third covering one degradation mode. These three composite trees form the basis for selection of test conditions in the final test plan which is now being prepared

Ultrathin epitaxial Fe films in vicinal GaAs(001): A study by spin-resolved photoelectron spectroscopy

Thin epitaxial Fe films have been grown on vicinal GaAs(001) substrates and their remanent magnetic properties and the degree of substrate atom diffusion investigated using synchrotron-based photoelectron spectroscopy. The vicinal Fe films, though exhibiting greater As diffusion than their singular homologues, displayed better film quality both from the structural and the magnetic points of view. The spin-resolved valence spectra of the vicinal films resemble those for crystalline bulk Fe at lower film thicknesses than for singular films

Unexpected Management Choices When Accounting for Uncertainty in Ecosystem Service Tradeoff Analyses

Resource management and conservation increasingly focus on ecosystem service provisioning and potential tradeoffs among services under different management actions. Application of bioeconomic approaches to tradeoffs assessment is touted as a way to find win-win outcomes or avoid unnecessary stakeholder conflict. Yet, nearly all assessments to date have ignored inherent uncertainties in the provision and valuation of services. We incorporate uncertainty into the ecosystem services analytical framework and show how such inclusion improves optimal decision making. In particular, we show: (1) “suboptimal” solutions can become optimal when uncertainties are accounted for; (2) uncertainty paradoxically makes stakeholders value conservation despite their lack of preference for it; and (3) substantial losses or missed gains in ecosystem service provisioning can be incurred when uncertainty is ignored. Our results highlight the urgency of accounting for uncertainties in ecosystem services in tradeoff assessments given the widespread use of this approach by government agencies and conservation organizations

Designing MPAs for food security in open-access fisheries

Food security remains a principal challenge in the developing tropics where communities rely heavily on marine-based protein. While some improvements in fisheries management have been made in these regions, a large fraction of coastal fisheries remain unmanaged, mismanaged, or use only crude input controls. These quasi-open-access conditions often lead to severe overfishing, depleted stocks, and compromised food security. A possible fishery management approach in these institution-poor settings is to implement fully protected marine protected areas (MPAs). Although the primary push for MPAs has been to solve the conservation problems that arise from mismanagement, MPAs can also benefit fisheries beyond their borders. The literature has not completely characterized how to design MPAs under diverse ecological and economic conditions when food security is the objective. We integrated four key biological and economic variables (i.e., fish population growth rate, fish mobility, fish price, and fishing cost) as well as an important aspect of reserve design (MPA size) into a general model and determined their combined influence on food security when MPAs are implemented in an open-access setting. We explicitly modeled open-access conditions that account for the behavioral response of fishers to the MPA; this approach is distinct from much of the literature that focuses on assumptions of “scorched earth” (i.e., severe over-fishing), optimized management, or an arbitrarily defined fishing mortality outside the MPA’s boundaries. We found that the MPA size that optimizes catch depends strongly on economic variables. Large MPAs optimize catch for species heavily harvested for their high value and/or low harvesting cost, while small MPAs or no closure are best for species lightly harvested for their low value and high harvesting cost. Contrary to previous theoretical expectations, both high and low mobility species are expected to experience conservation benefits from protection, although, as shown previously, greater conservation benefits are expected for low mobility species. Food security benefits from MPAs can be obtained from species of any mobility. Results deliver both qualitative insights and quantitative guidance for designing MPAs for food security in open-access fisheries

Overview and status of the 0.5NA EUV microfield exposure tool at Berkeley Lab

A 0.5-NA extreme ultraviolet micro-field exposure tool has been installed and commissioned at beamline 12.0.1.4 of the Advanced Light Source synchrotron facility at Lawrence Berkeley National Laboratory. Commissioning has demonstrated a patterning resolution of 13 nm half-pitch with annular 0.35-0.55 illumination; a patterning resolution of 8 nm half-pitch with annular 0.1-0.2 illumination; critical dimension (CD) uniformity of 0.7 nm 1σ on 16 nm nominal CD across 80% of the 200 um x 30 um aberration corrected field of view; aerial image vibration relative to the wafer of 0.75 nn RMS and focus control and focus stepping better than 15 nm

Laparoscopic Versus Open Nissen Fundoplication in Infants After Neonatal Laparotomy

BACKGROUND: Nissen fundoplication is an effective treatment of gastroesophageal reflux in infants. Laparoscopic procedures after previous laparotomy are technically more challenging. The role of laparoscopic Nissen fundoplication after neonatal laparotomy for diseases unrelated to reflux is poorly described. METHODS: This was a retrospective review of open vs laparoscopic Nissen fundoplication in infants after neonatal laparotomy. Of 32 infants who underwent neonatal laparotomy, 26 required a surgical antireflux operation within the first year of life. Twelve infants underwent laparoscopic Nissen fundoplication versus 14 infants who underwent open Nissen fundoplication. Parameters like age, weight, operative time, number of previous operations, length of stay following fundoplication, time to feedings, and complications were compared between the 2 groups. RESULTS: No statistically significant differences existed between most of the parameters compared following laparoscopic vs open Nissen fundoplication. No conversions to open procedures were necessary in infants undergoing laparoscopic fundoplication, and these infants resumed enteral feeds earlier than those who underwent the open procedure. CONCLUSION: Laparoscopic compared with open Nissen fundoplication performed in infants after a neonatal laparotomy were comparable procedures across most data points studied. However, a laparoscopic fundoplication did allow for earlier return to enteral feeds compared with the open approach. Laparoscopic Nissen fundoplication is technically feasible, safe, and effective in the treatment of gastroesophageal reflux in infants with a previous neonatal laparotomy

Fabrication of Large Domain YBa2Cu3O(x) for Magnetic Suspension Applications

Large domain YBa2Cu3O(x) levitators have been fabricated using a seeded melt processing technique. Depending upon the seed, either a single or five domained sample can be obtained. The grain boundaries separating each domains in the five domain levitator are found to be 90 degrees. Similar levitation forces can be observed for single and five domained samples. After thermal cycling, however, a small decrease in the levitation force of the five domain levitator was observed as a function of thermal cycles while nearly no change in force was observed in the single domain levitator. Finally, it is shown that both, single and five domain YBCO, behave similarly as a function of sample thickness