Riparian Functional Assessment Phase Two Summary

This report contains data regarding the drainage area, restoration strategy and banks sampled of three Waller Creek locations.In an effort to assess the response of degraded riparian buffers to the cessation of the main disturbance regime (mowing) and the facilitated succession approach to riparian restoration, the City of Austin implemented phase 2 of the Riparian Functional Assessment (RFA) which consisted of sampling degraded buffers after 1 year with no disturbance. Only degraded sites were included in this phase and their functional scores were compared with those of reference sites from the initial sample year representing healthy riparian function. A total of 9 degraded sites were added to the initial 16 degraded sites from phase 1 for this assessment. Results suggest that degraded buffers lacked the necessary time to show a response in riparian function after only one year of recovery. Sampling design changes are recommended to better assess the growing number of buffer site locations tracked in this project, including reinstituting reference site sampling and shifting to a biannual sampling regime. Based on analysis of phase 2 data, changes to the assessment tool include the following: substitute organic soil carbon for direct soil moisture measurements, coalesce the hardwood demography and recruitment parameters into woody community dynamics, and upgrade soil compaction instruments for higher accuracy and reliability.Waller Creek Working Grou

Portfolio choice and the effects of liquidity

This paper shows how to introduce liquidity into the well known mean-variance framework of portfolio selection. Either by estimating mean-variance liquidity constrained frontiers or directly estimating optimal portfolios for alternative levels of risk aversion and preference for liquidity, we obtain strong effects of liquidity on optimal portfolio selection. In particular, portfolio performance, measured by the Sharpe ratio relative to the tangency portfolio, varies significantly with liquidity. Moreover, although mean-variance performance becomes clearly worse, the levels of liquidity on optimal portfolios obtained when there is a positive preference for liquidity are much lower than on those optimal portfolios where investors show no sign of preference for liquidity.Liquidity, mean-variance frontiers, performance, portfolio selection

Interaction and imitation in a world of Quixotes and Sanchos

Producción CientíficaThis paper studies a two-population evolutionary game in a new setting in between a symmetric and an asymmetric evolutionary model. It distinguishes two types of agents: Sanchos, whose payoffs are defined by a prisoner’s dilemma game, and Quixotes, whose payoffs are defined by a snowdrift game. Considering an imitative revision protocol, a revising agent is paired with someone from his own population or the other population. When matched, they observe payoffs, but not identities. Thus, agents in one population interact and imitate agents from their own population and from the other population. In this setting we prove that a unique mixed-strategy asymptotically stable fixed point of the evolutionary dynamics exists. Taking as an example the compliance with social norms, and depending on the parameters, two type of equilibrium are possible, one with full compliance among Quixotes and partial compliance among Sanchos, or another with partial compliance among Quixotes and defection among Sanchos. In the former type, Sanchos comply above their Nash equilibrium (as they imitate compliant Quixotes). In the latter type, Quixotes comply below their Nash equilibrium (as they imitate defecting Sanchos)

Assessment of heritage rammed-earth buildings. The Alcázar of King Don Pedro I (Spain).

The conservation and maintenance of earthen buildings is crucial, especially when dealing with heritage sites. This normally involves considerable effort in preliminary studies, which must be well planned in order to efficiently manage any restoration. This case study proposes a methodology to briefly assess the current state of a historical rammed-earth wall, to bring to light specific information regarding approaches for subsequent studies or decisions. This methodology is based on the study of damage and risk as a tool to swiftly discern critical areas or issues needing immediate attention. The procedure is illustrated on an outstanding heritage building: the Alcázar of King Don Pedro I in Carmona (Seville, Spain). Our conclusions confirm that this methodology constitutes an efficient and straightforward means to obtain not only a preliminary assessment of rammed-earth walls, but also objective and useful criteria for decision-makers

Assessment of carotenoid production by Dunaliella salina in different culture systems and operation regimes

The effect of operation regime and culture system on carotenoid productivity by the halotolerant alga Dunaliella salina has been analyzed. Operation strategies tested included batch and semi continuous regime, as well as a two-stage approach run simultaneously in both, open tanks and closed reactor. The best results were obtained with the closed tubular photobioreactor. The highest carotenoid production (328.8 mg carotenoid l−1 culture per month) was achieved with this culture system operated following the two-stage strategy. Also, closed tubular photobioreactor provided the highest carotenoid contents (10% of dry weight) in Dunaliella biomass and β-carotene abundance (90% of total carotenoids) as well as the highest 9-cis to all-trans β-carotene isomer ratio (1.5 at sunrise).Comisión Interministerial de Ciencia y Tecnología IFD 1997-1780IFAPA CO3-125Plan Andaluz de Investigación CVI13