Ecosystem responses to channel restoration decline with stream size in urban river networks.

Urban streams are often severely impaired due to channelization, high loads of nutrients and contaminants, and altered land cover in the watershed. Physical restoration of stream channels is widely used to offset the effects of urbanization on streams, with the goal of improving ecosystem structure and function. However, these efforts are rarely guided by strategic analysis of the factors that mediate the responsiveness of stream ecosystems to restoration. Given that ecological gradients from headwater streams to mainstem rivers are ubiquitous, we posited that location within a river network could mediate the benefits of channel restoration. We studied existing stream restorations in Milwaukee, Wisconsin, to determine (1) whether restorations improve ecosystem function (e.g., nutrient uptake, whole-stream metabolism) and (2) how ecosystem responses vary by position in the urban river network. We quantified a suite of physicochemical and biological metrics in six pairs of contiguous restored and concrete channel reaches, spanning gradients in baseflow discharge (19-196 L/s) and river network position (i.e., headwater to mainstem). Hydrology differed dramatically between the restored and concrete reaches; water velocity was reduced 2- to 13-fold while water residence time was 50-5,000% greater in adjacent restored reaches. Restored reaches had shorter nutrient uptake lengths for ammonium, nitrate, and phosphate, as well as higher whole-stream metabolism. Furthermore, the majority of reaches were autotrophic (i.e., gross primary production > ecosystem respiration), which is not common in stream ecosystems. The difference in ecosystem functioning between restored and unrestored reaches was generally largest in headwaters and declined to equivalence in mainstem restorations. Our results suggest that headwater sites offer higher return on investment compared to larger downstream channels, where ecosystem responsiveness is low. If this pattern proves to be general, the scaling of ecosystem responses with river size could be integrated into planning guidelines for urban stream restorations to enhance the societal and ecological benefits of these expensive interventions.

Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products.

Chemical products are ubiquitous in modern society. The chemical sector is the largest industrial energy consumer and the third largest industrial emitter of carbon dioxide. The current portfolio of mitigation options for the chemical sector emphasizes upstream "supply side" solutions, whereas downstream mitigation options, such as material efficiency, are given comparatively short shrift. Key reasons for this are the scarcity of data on the sector's material flows, and the highly intertwined nature of its complex supply chains. We provide the most up to date, comprehensive and transparent data set available publicly, on virgin production routes in the chemical sector: from fossil fuel feedstocks to chemical products. We map global mass flows for the year 2013 through a complex network of transformation processes, and by taking account of secondary reactants and by-products, we maintain a full mass balance throughout. The resulting data set partially addresses the dearth of publicly available information on the chemical sector's supply chain, and can be used to prioritise downstream mitigation options.

A validated value-based model to improve hospital-wide perioperative outcomes: adaptability to combined medical/surgical inpatient cohorts.

OBJECTIVES: Authors hypothesized that building safe hospital systems to improve value-based surgical outcomes is predicated on workflow redesign for dynamic risk stratification, coupled with "real-time" mitigation of risk. We developed a comanagement model for hospitalized surgical cohort, and determined whether this iterative process redesign for surgery will be adaptable to disparate hospital systems and will be beneficial for combined medical/surgical adult inpatients. CONTEXT: Concerns about preventable harm in hospitalized patients have generated a plethora of both, process-driven and outcome-based strategies in US Healthcare. Although comparison between hospitals is a common mechanism to drive quality, other innovative approaches are needed for real-time risk mitigation to improve outcomes. METHODS: Prospective implementation of Surgical Continuum of Care (SCoC) model in hospitals initially for surgery patients; subsequently Continuum of Care (CoC) for medical/surgical population. Redesign of hospital care delivery model: patient cohorting, floor-based team building, and intensivist/hospitalist staffing of progressive care unit (PCU). Work flow redesign for clinical effectiveness: multidisciplinary team rounds, acuity stratified care rounding based on dynamic risk assessment into a novel HAWK (high risk)/DOVE (low risk) patient grouping, intensivist/hospitalist comanagement of surgical patients, and targeted response. STUDY: Pre- and postintervention with concurrent cohort control design. SETTING: Academic medical centers for SCoC and integrated health system hospital for CoC. PATIENT GROUPS: SCoC Pilot Study-Campus A: Preintervention control group 1998-2000, Intervention Group 2001-2004; Campus B: Comparator Control Group 1998-2004. SCoC Validation Study-Campus C: Preintervention Group 2001-2005; Intervention Group 2006-2008. CoC Study-Campus D: Hospital-wide Group 2009. METRICS: Mortality, length of stay (LOS): overall, surgical intensive care unit and PCU, readmission rates, and cost. Case mix index for risk adjustment. RESULTS: Total >100,000 admissions. There was a significant reduction in overall surgical mortality in both, pilot (P < 0.002) and validation (P < 0.02) SCoC studies and overall hospital mortality in the medical/surgical CoC study (risk-adjusted mortality index progressively declined in CoC study from 1.16 pre-CoC to 0.77 six months post-CoC implementation; significant at 75% confidence level). Case mix index was unchanged during study period in each campus. Nested study in validation cohort of hospital-wide versus surgery alone (observed/expected mortality index) demonstrated significant benefit to SCoC in intervention group. The mortality benefit was primarily derived from risk-stratified rounding and actively managing risk prone population in the PCU. Surgical intensive care unit, PCU, and total hospital patient-days significantly decreased in SCoC pilot study (P < 0.05), reflecting enhanced throughput. LOS reduction benefit persisted in SCoC validation and CoC studies. In addition to decreased LOS, cost savings were in PCU (range, $851,511-2,007,388) and top diagnosis-related groups, for example, $452 K/yr for diagnosis-related group 148. CONCLUSIONS: SCoC is patient-centered, outcomes-driven, value-based approach for hospital-wide surgical patient safety. The principles of this value paradigm are adaptable to other hospitals as demonstrated in our longitudinal study in 3 hospital systems, and the initial experience of CoC suggests that this model will have benefit beyond surgical hospital cohort.

Timber harvest transforms ecological roles of salmon in southeast Alaska rain forest streams.

Although species commonly modify habitats and thereby influence ecosystem structure and function, the factors governing the ecological importance of these modifications are not well understood. Pacific salmon have repeatedly been shown to positively influence the abundance of benthic biota by annually transferring large quantities of nutrients from marine systems to the nutrient-poor freshwaters in which they spawn. Conversely, other studies have demonstrated that salmon can negatively influence the abundance of freshwater biota, an effect attributed to bioturbation during upstream migration and nest construction. The factors determining which of these contrasting ecological effects predominates are unknown, including how human activities, such as land use, influence ecological responses to salmon. We sampled a key basal food resource, sediment biofilm, in seven southeast Alaskan streams impacted to varying degrees by timber harvest. Biofilm abundance (measured as chlorophyll a and ash-free dry mass) was positively related to timber-harvest intensity prior to salmon arrival. However, during the salmon run, an inverse relationship emerged of more abundant biofilm in less-harvested watersheds. Among-stream variability in biofilm response to salmon was largely explained by sediment particle size, which was larger in less-harvested watersheds. Collectively, these results suggest that, by altering stream sediment size, timber harvest transformed the dominant effect of salmon from nutrient enrichment to physical disturbance, thus modifying nutrient linkages between marine and freshwater ecosystems.