Bird ecology and conservation in Peru\u27s high Andean petlands

High in the Andes, a unique peatland habitat exists precariously above the frostline and below snowline. These “bofedales”, as they are called in Peru, support an extraordinary avifauna consisting of both boreal and austral migratory species and residents. This ecosystem is predicted to be significantly reduced as a result of global climate change. We endeavored to understand the habitat associations and seasonality of the avian assemblage occurring in these permanent wetlands. Numerous detections of species outside of their documented geographic range provided an opportunity to assess geographic ranges using niche modeling. This novel approach provided insights and inferences for assessing geographic ranges. Peatland study sites were visited in both the wet and dry season and habitat and seasonality associations were determined for the majority of species occurring therein. Peatlands are an important habitat for many migratory and resident bird species and seasonality is strong for many species. With the threat of climate change predicted for the Andes, we modeled the presence of peatland habitat for a large area of southern Peru using ground-truthed study sites and assessed the effects of the temperature change for these peatlands. Our model showed peatlands represent approximately 5% of the Puna. Peatland occurrence is correlated with several environmental variables including flow accumulation and presence of glaciers in the watershed. Using the model of peatland occurrence, we predicted what percentage of peatland habitat would no longer occur within the required climatic envelope. Within our study area, more than 75% of the peatlands would no longer occur above the frost line using temperature predictions for the next 80 years. In effect, habitat for already rare and isolated bird species will be dramatically reduced by weather alone. The additional pressures of pastoralism, peat harvesting, agriculture, and water diversion projects suggest these peatlands should be prioritized for conservation assessment and action. Finally, we identified several areas within our study area that are most likely to persist through the precipitation and temperature changes through the end of the century

Iodine sorption study on the proposed use of Viton A in a shuttle galley water accumulator

The installation of a Viton A accumulator in the Shuttle galley has been proposed to prevent overpressurization of the hot water supply system. A laboratory study has been conducted to determine if there would be any interaction between the Viton A material and the iodine used to disinfect the water. Coupons of Viton A were exposed for 24 hours to aqueous iodine solutions similar in quality to the Shuttle's potable water. Changes in the iodine residual were monitored to determine the rate of iodine sorption by the coupon. Total organic carbon (TOC) was monitored to determine the rate of desorption of organic materials from the Viton A. The same coupons were then soaked in reagent-grade water for 24 hours, and iodine was monitored to determine the rate of iodine desorption. The coupons were again exposed to iodine solutions for 24 hours and iodine and TOC were monitored. No significant change in the iodine sorption rate was detected between the first and second exposures. A triangle taste test indicated at a 1 percent confidence level that the water exposed to Viton A had a different taste which was less acceptable to the panelists

Integration and Information: Markets and Hierarchies Revisited

We analyze a rational-expectations model of price formation in an intermediate-good market under uncertainty. There is a continuum of dyads, each consisting of an upstream party and downstream party. Both parties can make specific investments at private cost, and there is a machine that either party can own. As in property rights models, different ownership structures create different incentives for the parties' investments. As in rational-expectations models, some parties may invest in acquiring information, which is then incorporated into the market-clearing price by the parties' trading behaviors. The informativeness of the price mechanism affects the returns to specific investments and hence the optimal ownership structure for individual dyads; meanwhile, the ownership choices by individual dyads affect the informativeness of the price mechanism. In equilibrium the informativeness of the price mechanism can induce ex ante homogeneous dyads to choose heterogeneous ownership structures.All three authors thank MIT Sloan's Program on Innovation in Markets and Organizations for financial support, and Powell also thanks the NSF

Student satisfaction, league tables and University applications

We investigate the impact of information about student satisfaction on university choice, using data from the UK’s National Student Survey (NSS) and on applications to undergraduate degree courses. We show that the NSS has a small, statistically significant effect on applications at the university-subject level. This effect operates primarily through the influence of the NSS scores on a university’s position in separately published, subject-specific, league tables, implying greater salience of league table rankings. The impact of rankings is greater amongst the most able students, for universities with entry standards in the upper-middle tier, and for subject-departments facing more competition

Student satisfaction, league tables and university applications: evidence from Britain

We investigate the impact of information about student satisfaction on university choice, using data from the UK's National Student Survey (NSS) and on applications to undergraduate degrees. We show that NSS scores have a small statistically significant effect on applications at the university-subject level. This effect operates via the influence of the NSS on a university's position in separately published, subject-specific league tables, suggesting that information contained in the league table rankings is more salient. The impact of rankings is greater for more able students, for universities with entry standards in the upper-middle tier, and for subject-departments facing more competition

Firms In Markets Under Uncertainty

We analyze a rational-expectations model of price formation in an intermediate-good market under uncertainty. There is a continuum of dyads, each consisting of an upstream party and a downstream party. Both parties can make specific investments at private cost. As in property-rights models, different governance structures induce different investments. As in rational-expectations models, some parties may invest in acquiring (common-value) information, which is then incorporated into the market-clearing price by the parties' trading behaviors. The informativeness of the price mechanism affects the returns to specific investments and hence the optimal governance structure for individual dyads; meanwhile, the governance-structure choices by individual dyads affect the informativeness of the price mechanism. In equilibrium, firms and the market coexist and shape each other. In particular, the informativeness of the price mechanism can induce ex ante homogeneous dyads to choose heterogeneous governance structures.We thank MIT's Program on Innovation in Markets and Organizations for financial support. Powell thanks the NSF for financial support

Correspondence between Minkowski and de Sitter Quantum Field Theory

In this letter we show that the ``preferred'' Klein-Gordon Quantum Field Theories (QFT's) on a d-dimensional de Sitter spacetime can be obtained from a Klein-Gordon QFT on a (d+1)-dimensional ``ambient'' Minkowski spacetime satisfying the spectral condition and, conversely, that a Klein-Gordon QFT on a (d+1)-dimensional ``ambient'' Minkowski spacetime satisfying the spectral condition can be obtained as superposition of d-dimensional de Sitter Klein-Gordon fields in the preferred vacuum. These results establish a correspondence between QFT's living on manifolds having different dimensions. The method exposed here can be applied to study other situations and notably QFT on Anti de Sitter spacetime.Comment: 7 pages, no figures, typos corrected, added one referenc