Evaluating the Effectiveness of Wood Shreds on Post-fire Erosion

Agricultural straw mulching is a commonly used post-fire hillslope erosion control treatment that is aerially applied by helicopter. While widely used and reasonably effective at reducing erosion, agricultural straw is not native to the forest environment. There is a growing consensus among Burned Area Emergency Response (BAER) teams that mulch made from native forest material would be preferable to agricultural straw. Wood shred mulch made from post-fire road hazard trees is an alternative to agricultural straw. An optimized blend of sizes of wood shreds was effective in reducing sediment yields in both indoor rainfall simulation and outdoor field experiments. Several post-wildfire field experiments showed that wood shreds and agricultural straw were effective in reducing sediment yields as compared to the controls but neither treatment had an effect on runoff. Erosion reductions from wood shred treatments ranged from 50-96% in these experiments, and the presence and effectiveness of wood shreds appears to outlast both agricultural straw and hydromulch. Wood shreds are denser than agricultural straw and, as a consequence, about 4 times more wood shreds (by weight) than straw are needed to provide the same ground cover in a designated area. As a result, a helicopter with cargo nets required about four to five times as many round trips to treat an acre with wood shreds as with agricultural straw. This made wood shred application take longer and cost more than agricultural straw ($1,500 to$2,000 per acre [$3,750 to$5,000 per ha] and $500 per acre [$1,250 per ha], respectively). Field tests using a Heli-Claw, an alternative to a cargo net for heli-mulching, suggest that the Heli-Claw is a viable option for the aerial application of wood shreds. Results from these studies were disseminated through publications and a wide range of presentations, such as webinars, national meetings, and regional specialists meetings; thus, research findings have been directly conveyed to BAER teams and land managers. [Note: Throughout this report customary (English) units are stated first and metric equivalents are parenthetical where appropriate. The use of the symbol “t” is for ton (2000 lbs) in the customary system and the symbol “t” is for tonne (1000 kg [~2200 lbs]) in the metric system.

Past Decline Versus Current eGFR and Subsequent Mortality Risk

A single determination of eGFR associates with subsequent mortality risk. Prior decline in eGFR indicates loss of kidney function, but the relationship tomortality risk is uncertain. We conducted an individual–level meta-analysis of the risk ofmortality associatedwith antecedent eGFR slope, adjusting for established risk factors, including last eGFR, among 1.2million subjects from 12 CKD and 22 other cohorts within the CKD Prognosis Consortium. Over a 3-year antecedent period, 12% of participants in the CKD cohorts and 11% in the other cohorts had an eGFR slope,25ml/min per 1.73 m2 per year, whereas 7%and 4% had a slope .5 ml/min per 1.73 m2 per year, respectively. Compared with a slope of 0 ml/min per 1.73 m2 per year, a slope of 26 ml/min per 1.73 m2 per year associated with adjusted hazard ratios for all-cause mortality of 1.25 (95% confidence interval [95% CI], 1.09 to 1.44) among CKD cohorts and 1.15 (95% CI, 1.01 to 1.31) among other cohorts during a follow-up of 3.2 years. A slope of +6 ml/min per 1.73 m2 per year also associated with higher all–cause mortality risk, with adjusted hazard ratios of 1.58 (95% CI, 1.29 to 1.95) among CKD cohorts and 1.43 (95% CI, 1.11 to 1.84) among other cohorts. Results were similar for cardiovascular and noncardiovascular causes of death and stronger for longer antecedent periods (3 versus ,3 years). We conclude that prior decline or rise in eGFR associates with an increased risk of mortality, independent of current eGFR

Cohort Profile: The Chronic Kidney Disease Prognosis Consortium.

The Chronic Kidney Disease Prognosis Consortium (CKD-PC) was established in 2009 to provide comprehensive evidence about the prognostic impact of two key kidney measures that are used to define and stage CKD, estimated glomerular filtration rate (eGFR) and albuminuria, on mortality and kidney outcomes. CKD-PC currently consists of 46 cohorts with data on these kidney measures and outcomes from >2 million participants spanning across 40 countries/regions all over the world. CKD-PC published four meta-analysis articles in 2010-11, providing key evidence for an international consensus on the definition and staging of CKD and an update for CKD clinical practice guidelines. The consortium continues to work on more detailed analysis (subgroups, different eGFR equations, other exposures and outcomes, and risk prediction). CKD-PC preferably collects individual participant data but also applies a novel distributed analysis model, in which each cohort runs statistical analysis locally and shares only analysed outputs for meta-analyses. This distributed model allows inclusion of cohorts which cannot share individual participant level data. According to agreement with cohorts, CKD-PC will not share data with third parties, but is open to including further eligible cohorts. Each cohort can opt in/out for each topic. CKD-PC has established a productive and effective collaboration, allowing flexible participation and complex meta-analyses for studying CK

Age and association of kidney measures with mortality and end-stage renal disease

CONTEXT: Chronic kidney disease (CKD) is prevalent in older individuals, but the risk implications of low estimated glomerular filtration rate (eGFR) and high albuminuria across the full age range are controversial.OBJECTIVE: To evaluate possible effect modification (interaction) by age of the association of eGFR and albuminuria with clinical risk, examining both relative and absolute risks.DESIGN, SETTING, AND PARTICIPANTS: Individual-level meta-analysis including 2,051,244 participants from 33 general population or high-risk (of vascular disease) cohorts and 13 CKD cohorts from Asia, Australasia, Europe, and North/South America, conducted in 1972-2011 with a mean follow-up time of 5.8 years (range, 0-31 years).MAIN OUTCOME MEASURES: Hazard ratios (HRs) of mortality and end-stage renal disease (ESRD) according to eGFR and albuminuria were meta-analyzed across age categories after adjusting for sex, race, cardiovascular disease, diabetes, systolic blood pressure, cholesterol, body mass index, and smoking. Absolute risks were estimated using HRs and average incidence rates.RESULTS: Mortality (112,325 deaths) and ESRD (8411 events) risks were higher at lower eGFR and higher albuminuria in every age category. In general and high-risk cohorts, relative mortality risk for reduced eGFR decreased with increasing age; eg, adjusted HRs at an eGFR of 45 mL/min/1.73 m2 vs 80 mL/min/1.73 m2 were 3.50 (95% CI, 2.55-4.81), 2.21 (95% CI, 2.02-2.41), 1.59 (95% CI, 1.42-1.77), and 1.35 (95% CI, 1.23-1.48) in age categories 18-54, 55-64, 65-74, and ?75 years, respectively (P <.05 for age interaction). Absolute risk differences for the same comparisons were higher at older age (9.0 [95% CI, 6.0-12.8], 12.2 [95% CI, 10.3-14.3], 13.3 [95% CI, 9.0-18.6], and 27.2 [95% CI, 13.5-45.5] excess deaths per 1000 person-years, respectively). For increased albuminuria, reduction of relative risk with increasing age was less evident, while differences in absolute risk were higher in older age categories (7.5 [95% CI, 4.3-11.9], 12.2 [95% CI, 7.9-17.6], 22.7 [95% CI, 15.3-31.6], and 34.3 [95% CI, 19.5-52.4] excess deaths per 1000 person-years, respectively by age category, at an albumin-creatinine ratio of 300 mg/g vs 10 mg/g). In CKD cohorts, adjusted relative hazards of mortality did not decrease with age. In all cohorts, ESRD relative risks and absolute risk differences at lower eGFR or higher albuminuria were comparable across age categories.CONCLUSIONS: Both low eGFR and high albuminuria were independently associated with mortality and ESRD regardless of age across a wide range of populations. Mortality showed lower relative risk but higher absolute risk differences at older age