Assessing Historical Fish Community Composition Using Surveys, Historical Collection Data, and Species Distribution Models

Accurate establishment of baseline conditions is critical to successful management and habitat restoration. We demonstrate the ability to robustly estimate historical fish community composition and assess the current status of the urbanized Barton Creek watershed in central Texas, U.S.A. Fish species were surveyed in 2008 and the resulting data compared to three sources of fish occurrence information: (i) historical records from a museum specimen database and literature searches; (ii) a nearly identical survey conducted 15 years earlier; and (iii) a modeled historical community constructed with species distribution models (SDMs). This holistic approach, and especially the application of SDMs, allowed us to discover that the fish community in Barton Creek was more diverse than the historical data and survey methods alone indicated. Sixteen native species with high modeled probability of occurrence within the watershed were not found in the 2008 survey, seven of these were not found in either survey or in any of the historical collection records. Our approach allowed us to more rigorously establish the true baseline for the pre-development fish fauna and then to more accurately assess trends and develop hypotheses regarding factors driving current fish community composition to better inform management decisions and future restoration efforts. Smaller, urbanized freshwater systems, like Barton Creek, typically have a relatively poor historical biodiversity inventory coupled with long histories of alteration, and thus there is a propensity for land managers and researchers to apply inaccurate baseline standards. Our methods provide a way around that limitation by using SDMs derived from larger and richer biodiversity databases of a broader geographic scope. Broadly applied, we propose that this technique has potential to overcome limitations of popular bioassessment metrics (e.g., IBI) to become a versatile and robust management tool for determining status of freshwater biotic communities

Inter-process buffers in separation logic with rely-guarantee

Separation logic allows simple proofs of concurrent algorithms which use blocking mechanisms such as semaphores. It can even deal with non-blocking algorithms. With the addition of mechanisms borrowed from rely-guarantee, we can make reasonably simple proofs of some simple non-blocking algorithms. We show that it extends to proofs of some intricate algorithms, including Simpson’s famous asynchronous four-slot buffer and Harris’s novel three-slot algorithm, in a manner that is arguably simpler than earlier treatments, though we cannot claim that we have yet found proofs that are as simple as we would wish. Our example proofs show functional correctness but do not deal with questions of liveness

Effectiveness of a campaign to implement chlorhexidine use for newborns in rural Haiti

Abstract Background Chlorhexidine topical cord application is recommended to prevent umbilical cord infections in newborns delivered at home in low-resource settings. A community campaign introducing chlorhexidine for the first time in Haiti was developed. Traditional birth attendants (TBAs) were identified as implementers since they typically cut newborns’ cords. TBAs were trained to apply chlorhexidine to the cord and demonstrate this procedure to the mother. Concurrently TBAs explained reasons for using chlorhexidine exclusively instead of traditional cord care practices. The campaign’s effectiveness was evaluated 7–10 days post-delivery using a survey administered by community health workers (CHWs) to 198 mothers. Results Nearly all mothers heard about chlorhexidine use and applied it as instructed. Most mothers did not initially report using traditional cord care practices. With further probing, the majority reported covering the cord but few applied an unhygienic substance. No serious cord infections were reported. Conclusion The campaign was highly successful in reaching mothers and achieving chlorhexidine use. In this study, the concomitant use of traditional cloth coverings or bindings of the cord did not appear harmful; however more research is needed in this area. This campaign provides a model for implementing chlorhexidine use, especially where trained TBAs and CHWs are present