Asymmetric response of forest and grassy biomes to climate variability across the African Humid Period : influenced by anthropogenic disturbance?

A comprehensive understanding of the relationship between land cover, climate change and disturbance dynamics is needed to inform scenarios of vegetation change on the African continent. Although significant advances have been made, large uncertainties exist in projections of future biodiversity and ecosystem change for the world's largest tropical landmass. To better illustrate the effects of climate–disturbance–ecosystem interactions on continental‐scale vegetation change, we apply a novel statistical multivariate envelope approach to subfossil pollen data and climate model outputs (TraCE‐21ka). We target paleoenvironmental records across continental Africa, from the African Humid Period (AHP: ca 14 700–5500 yr BP) – an interval of spatially and temporally variable hydroclimatic conditions – until recent times, to improve our understanding of overarching vegetation trends and to compare changes between forest and grassy biomes (savanna and grassland). Our results suggest that although climate variability was the dominant driver of change, forest and grassy biomes responded asymmetrically: 1) the climatic envelope of grassy biomes expanded, or persisted in increasingly diverse climatic conditions, during the second half of the AHP whilst that of forest did not; 2) forest retreat occurred much more slowly during the mid to late Holocene compared to the early AHP forest expansion; and 3) as forest and grassy biomes diverged during the second half of the AHP, their ecological relationship (envelope overlap) fundamentally changed. Based on these asymmetries and associated changes in human land use, we propose and discuss three hypotheses about the influence of anthropogenic disturbance on continental‐scale vegetation change

Homelessness And Reentry: A Multisite Outcome Evaluation Of Washington State\u27S Reentry Housing Program For High Risk Offenders

Each year many offenders are released homeless putting them at great risk of being returned to prison. To reduce the likelihood of recidivism, Washington State implemented the Reentry Housing Pilot Program (RHPP) to provide housing assistance for high risk/high need offenders leaving prison without a viable place to live. This study provides a longitudinal (2008-2011), multisite outcome evaluation that considers how ex-offenders in the RHPP program (n = 208), who were provided housing and wraparound services, compared with similar offenders released with an elevated risk of homelessness while being traditionally supervised (n = 208). Findings show that the RHPP program was successful in significantly reducing new convictions and readmission to prison for new crimes, but had no significant effect on revocations. In addition, results showed that periods of homelessness significantly elevated the risk of recidivism for new convictions, revocations, and readmission to prison. The authors recommend that subsidized housing for high risk offenders become a central part of coordinated responses to reentry. © 2013 International Association for Correctional and Forensic Psychology

Stabilized potentiometric solid-state polyion sensors using silver-calixarene complexes as additives within ion-exchanger-based polymeric films

Novel solid-state sensors for biomedically important polyions (i.e., heparin and protamine) that exhibit significantly enhanced initial EMF stability are prepared by incorporation of lipophilic silver-calixarene complexes along with the required ion-exchangers within polymeric films. A dithioether of tertiary butyl calix[4]arene together with its silver complex are added to the polyion sensing membranes which are deposited on a silver-epoxy conductor of a solid-state transducer. The silver-complex serves as a reversible electron transfer agent between the organic polymer film and the underlying solid-state conductor, resulting in highly reproducible starting EMF values and improved initial signal stability. This approach is further employed to devise a heparin sensing cartridge for blood measurements based on a novel differential measurement mode. One sensor responds to heparin, while the second identical solid-state sensor serves as a pseudo reference electrode with all heparin present in the sample within this half-cell complexed by the addition of excess protamine. The cartridges are evaluated by monitoring heparin response in spiked dog blood using poly(vinyl chloride) (PVC) blends and fluorinated silicone rubber (Dow Corning RTV 730) films containing appropriate levels of ion-exchanger and Ag + -calixarene/free calixarene additives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41988/1/216-364-1-2-41_93640041.pd