7 research outputs found

    Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA

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    The Biological Condition Gradient (BCG) is a conceptual model that describes changes in aquatic communities under increasing levels of anthropogenic stress. The BCG helps decision-makers connect narrative water quality goals (e.g., maintenance of natural structure and function) to quantitative measures of ecological condition by linking index thresholds based on statistical distributions (e.g., percentiles of reference distributions) to expert descriptions of changes in biological condition along disturbance gradients. As a result, the BCG may be more meaningful to managers and the public than indices alone. To develop a BCG model, biological response to stress is divided into 6 levels of condition, represented as changes in biological structure (abundance and diversity of pollution sensitive versus tolerant taxa) and function. We developed benthic macroinvertebrate (BMI) and algal BCG models for California perennial wadeable streams to support interpretation of percentiles of reference-based thresholds for bioassessment indices (i.e., the California Stream Condition Index [CSCI] for BMI and the Algal Stream Condition Index [ASCI] for diatoms and soft-bodied algae). Two panels (one of BMI ecologists and the other of algal ecologists) each calibrated a general BCG model to California wadeable streams by first assigning taxa to specific tolerance and sensitivity attributes, and then independently assigning test samples (264 BMI and 248 algae samples) to BCG Levels 1–6. Consensus on the assignments was developed within each assemblage panel using a modified Delphi method. Panels then developed detailed narratives of changes in BMI and algal taxa that correspond to the 6 BCG levels. Consensus among experts was high, with 81% and 82% expert agreement within 0.5 units of assigned BCG level for BMIs and algae, respectively. According to both BCG models, the 10th percentiles index scores at reference sites corresponded to a BCG Level 3, suggesting that this type of threshold would protect against moderate changes in structure and function while allowing loss of some sensitive taxa. The BCG provides a framework to interpret changes in aquatic biological condition along a gradient of stress. The resulting relationship between index scores and BCG levels and narratives can help decision-makers select thresholds and communicate how these values protect aquatic life use goals

    Performance benefits and costs for children using cochlear implants and hearing aids [Abstract]

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    The value of cochlear implants as an established clinical option for profoundly hearing impaired adults and children has been supported by significant research results over a number of years which has clearly established the benefits available (U.S. National Institutes of Health Consensus Statement 1995). Benefit has traditionally been considered as the direct impact of the cochlear implant procedure on speech perception, or in the case of children, on the use of that auditory information to develop understandable speech and to acquire a knowledge of language. As a consequence of continuing research to improve hardware and speech processing strategies, mean scores on open-set tests of monosyllables or sentence materials for implanted adults using the cochlear implant alone without lipreading have continued to show an upwards trend. In response to the increased mean scores in quiet, perception tests in background noise are now being used as a more accurate direct measure of the potential benefits of cochlear implants to severely-to-profoundly hearing-impaired candidates. Consideration should also be given to indirect benefits, such as reduction in the stress of listening and lipreading, improved performance at work, enhanced opportunity to maintain speech, or in children to develop speech which is understandable to the general community, and the social effects of reducing the isolating effects of profound deafness. Measurement of indirect benefit can be combined with an analysis of the costs of the procedure, enabling evaluation of the implant procedure from a cost-utility standpoint, and a comparison of outcomes using other technologies such as hearing aids. This study will present data on direct and indirect benefits for hearing-impaired children using Nucleus cochlear implant systems, and compare this data with benefits shown for similarly hearing impaired children using hearing aids. The significance of these results to cost-effective delivery of services will be discussed.14-17 Jun

    The Special Court for Sierra Leone’s Consideration of Gender-based Violence: Contributing to Transitional Justice?

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    Serious gender-based crimes were committed against women and girls during Sierra Leone’s decade-long armed conflict. This article examines how the Special Court for Sierra Leone has approached these crimes in its first four judgments. The June 20, 2007 trial judgment in the Armed Forces Revolutionary Council case assists international criminal law’s limited understanding of the crime against humanity of forced marriage, but also collapses evidence of that crime into the war crime of outrages upon personal dignity. The February 22, 2008 appeals judgment attempts to correct this misstep. In contrast, the August 2, 2007 trial judgment in the Civil Defence Forces case is virtually silent on crimes committed against women and girls, although the May 28, 2008 appeals judgment attempts to partially redress this silence. This article concludes that the four judgments, considered together, raise the specter that the Special Court could potentially fail to make a significant progressive contribution to gender-sensitive transitional justice
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