Silver Lake is the modern terminal playa of the Mojave River in southern California (USA). As a result, it is well located to record both influences from the winter precipitation dominated San Bernardino Mountains – the source of the Mojave River – and from the late summer to early fall North American monsoon at Silver Lake. Here, we present various physical, chemical and biological data from a new radiocarbon-dated, 8.2 m sediment core taken from Silver Lake that spans modern through 14.8 cal ka BP. Texturally, the core varies between sandy clay, clayey sand, and sand-silt-clay, often with abrupt sedimentological transitions. These grain-size changes are used to divide the core into six lake status intervals over the past 14.8 cal ka BP. Notable intervals include a dry Younger Dryas chronozone, a wet early Holocene terminating 7.8 – 7.4 cal ka BP, a distinct mid-Holocene arid interval, and a late Holocene return to ephemeral lake conditions. A comparison to potential climatic forcings implicates a combination of changing summer – winter insolation and tropical and N Pacific sea-surface temperature dynamics as the primary drivers of Holocene climate in the central Mojave Desert.

The Senior Companion Quality of Care Evaluation assessed the impact of a federally funded senior volunteer program on quality of life outcomes for frail clients and their families. Telephone interviews were conducted with national samples of frail Senior Companion Program (SCP) clients, family members, and comparison group participants. Multivariate procedures were used to examine study outcomes. SCP clients benefited significantly from the program at 3 months, though fewer positive effects were reported at 9 months. SCP family members benefited only modestly from the program. The SCP has been considered a low-cost way of matching the needs of community-based frail older adults with the skills of senior volunteers. Now, it has been shown to have some favorable effects on client well-being. These findings may take on greater significance given the desire to expand the SCP through the USA Freedom Corps Initiative.

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Objective Acute kidney injury (AKI) occurs early in pediatric intensive care unit (PICU) admission and increases risks for poor outcomes. We evaluated the feasibility of a multi-centre AKI biomarker urine collection protocol and measured diagnostic characteristics of urine neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18) and liver fatty acid binding protein (LFABP) to predict AKI and prolonged AKI. Design: Prospective observational pilot cohort study. Setting: Four Canadian tertiary healthcare PICUs. Patients: Eighty-one children 1 month-18 years old. Exclusions: cardiac surgery; baseline severe kidney disease; inadequate urine or serum for PICU days 1 to 3. Interventions: PICUs performed standardized urine collection protocol to obtain early PICU admission urine samples, with deferred consent. Measurements and main results: Study barriers and facilitators were recorded. AKI was defined based on Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine (SCr) criteria (AKISCr) and by SCr and urine output criteria (AKISCr+UO) Prolonged AKI was defined as AKI duration ≥48 hours. PICU days 1 to 3 NGAL, IL-18 and LFABP were evaluated for AKI prediction (area under the curve [AUC]). Biomarkers on the first day of AKI attainment (day 1 AKI) were evaluated for predicting prolonged AKI. Eighty-two to 95% of subjects had urine collected from PICU days 1 to 3. Sixteen subjects (20%) developed AKISCr; 38 (47%) developed AKISCr+UO. On PICU day 1, IL-18 predicted AKISCr with AUC=0.82, but NGAL and LFABP predicted AKISCr with AUC’s ≤0.69; on PICU day 2, AUC’s higher (not shown). IL-18 and LFABP on day 1 AKI predicted prolonged AKISCr (AUC’s 0.74 and 0.83, respectively). When AKISCr+UO was used to define AKI, biomarker AUC’s were globally lower. Conclusions: Protocol urine collection to procure early admission samples is feasible. Individual biomarker AKI prediction performance is highly variable and modest. Larger studies should evaluate utility and cost effectiveness of using early AKI biomarkers.