Preliminary economic assessment of water resources of the Pangani River Basin, Tanzania: economic values and incentives

River basinsEconomic analysisDomestic waterIrrigated farmingLivestockPolicyWater supplyFinancing

Preliminary economic assessment of water resources of the Pangani River Basin, Tanzania

River basin managementWater useWater allocationEconomic evaluationDomestic waterIrrigation waterLivestockWater power

THE ROLE OF ESTUARIES IN SOUTH AFRICAN FISHERIES: ECONOMIC IMPORTANCE AND MANAGEMENT IMPLICATIONS

Existing catch data for 129 of 255 functional estuaries on the South African coastline were reviewed and the relationships between fish catch and estuary size, type and biogeographical region analysed using simple and multivariate models. The best predictive models were obtained by analysing data separately for each biogeographical region. Estuary size alone explained >80&#37 of the variation in catch in the warm temperate region and >90&#37 of the variation in catch in the cool temperate and subtropical region. Further analysis of the two main estuary types, i.e. permanently open and temporarily open/closed estuaries revealed a steeper regression slope and therefore greater productivity for the permanently open systems. Estuary size (ha) and type (five) were used to explain catches within the warm temperate and subtropical regions using general linear models. The models were able to explain 82 and 98&#37 of the variance in catches for the two regions respectively, and both were significant (p &#60 0.001). These models were applied to estuary type and size data for all 246 estuaries in the two regions and a total catch of 1 840 tons per year was estimated. Including the cool temperate region the total estuarine catch in South Africa was estimated at 2 480 tons per year. In all, 50&#37 of the estuarine catch was attributed to commercial seine and gillnet fisheries, 46&#37 to recreational angling and 4&#37 to traditional trap and spear fisheries. Total catch value was R433 million per year, of which 99&#37 could be attributed to recreational angling. Estuarine contribution to the inshore marine fisheries was estimated at approximately R490 million per year, estuarydependent species constituting 83&#37of the catch of the recreational shore and commercial seine and gillnet fisheries and only 7&#37 of the catch of the recreational spearfishery and commercial and recreational boat fisheries. In 2002, the total value of estuarine and estuary-dependent fisheries was estimated to be R1.251 billion.Afr. J. mar. Sci. 25: 131–15

Evaluating the cost-effectiveness of ecosystem-based adaptation: Kamiesberg wetlands case study

Ecosystem-based adaptation (EbA) is increasingly being promoted as a cost-effective means of adaptation to climate change. However, in spite of considerable international press, there is still little evidence to substantiate this claim. This study proposes a method through which the cost-effectiveness of EbA strategies can be evaluated against alternative adaptation options, and contributes to South African literature on the subject. The potential cost-effectiveness of wetland restoration is assessed as a means of securing the carrying capacity of land for pastoralist communities of the Kamiesberg communal area in South Africa under projected future climate conditions. The conventional alternatives would be to respond to increasingly dry conditions by drilling boreholes and using supplemental feed for livestock. It was assumed that the EbA interventions would occur upfront, whereas the alternatives are more likely to be implemented in reaction to droughts over a longer time period. The study found the implementation of conventional alternatives to be more cost-effective than EbA as a means to sustaining livestock stocking rates, with EbA being twice as costly. However, this is framed from the perspective of those directly affected (the landowners), and does not include the benefits to broader society

Outcomes Associated With Oral Anticoagulants Plus Antiplatelets in Patients With Newly Diagnosed Atrial Fibrillation.

Importance: Patients with nonvalvular atrial fibrillation at risk of stroke should receive oral anticoagulants (OAC). However, approximately 1 in 8 patients in the Global Anticoagulant Registry in the Field (GARFIELD-AF) registry are treated with antiplatelet (AP) drugs in addition to OAC, with or without documented vascular disease or other indications for AP therapy. Objective: To investigate baseline characteristics and outcomes of patients who were prescribed OAC plus AP therapy vs OAC alone. Design, Setting, and Participants: Prospective cohort study of the GARFIELD-AF registry, an international, multicenter, observational study of adults aged 18 years and older with recently diagnosed nonvalvular atrial fibrillation and at least 1 risk factor for stroke enrolled between March 2010 and August 2016. Data were extracted for analysis in October 2017 and analyzed from April 2018 to June 2019. Exposure: Participants received either OAC plus AP or OAC alone. Main Outcomes and Measures: Clinical outcomes were measured over 3 and 12 months. Outcomes were adjusted for 40 covariates, including baseline conditions and medications. Results: A total of 24 436 patients (13 438 [55.0%] male; median [interquartile range] age, 71 [64-78] years) were analyzed. Among eligible patients, those receiving OAC plus AP therapy had a greater prevalence of cardiovascular indications for AP, including acute coronary syndromes (22.0% vs 4.3%), coronary artery disease (39.1% vs 9.8%), and carotid occlusive disease (4.8% vs 2.0%). Over 1 year, patients treated with OAC plus AP had significantly higher incidence rates of stroke (adjusted hazard ratio [aHR], 1.49; 95% CI, 1.01-2.20) and any bleeding event (aHR, 1.41; 95% CI, 1.17-1.70) than those treated with OAC alone. These patients did not show evidence of reduced all-cause mortality (aHR, 1.22; 95% CI, 0.98-1.51). Risk of acute coronary syndrome was not reduced in patients taking OAC plus AP compared with OAC alone (aHR, 1.16; 95% CI, 0.70-1.94). Patients treated with OAC plus AP also had higher rates of all clinical outcomes than those treated with OAC alone over the short term (3 months). Conclusions and Relevance: This study challenges the practice of coprescribing OAC plus AP unless there is a clear indication for adding AP to OAC therapy in newly diagnosed atrial fibrillation

Assessment of Outcomes Among Patients With Venous Thromboembolism With and Without Chronic Kidney Disease

Importance: Patients with venous thromboembolism (VTE) and concomitant chronic kidney disease (CKD) have been reported to have a higher risk of thrombosis and major bleeding complications compared with patients without concomitant CKD. The use of anticoagulation therapy is challenging, as many anticoagulant medications are excreted by the kidney. Large-scale data are needed to clarify the impact of CKD for anticoagulant treatment strategies and clinical outcomes of patients with VTE. Objective: To compare clinical characteristics, treatment patterns, and 12-month outcomes among patients with VTE and concomitant moderate to severe CKD (stages 3-5) vs patients with VTE and mild to no CKD (stages 1-2) in a contemporary international registry. Design, Setting, and Participants: The Global Anticoagulant Registry in the Field-Venous Thromboembolism (GARFIELD-VTE) study is a prospective noninterventional investigation of real-world treatment practices. A total of 10 684 patients from 415 sites in 28 countries were enrolled in the GARFIELD-VTE between May 2014 and January 2017. This cohort study included 8979 patients (6924 patients with mild to no CKD and 2055 patients with moderate to severe CKD) who had objectively confirmed VTE within 30 days before entry in the registry. Chronic kidney disease stages were defined by estimated glomerular filtration rates. Data were extracted from the study database on December 8, 2018, and analyzed between May 1, 2019, and July 30, 2020. Exposure: Moderate to severe CKD vs mild to no CKD. Main Outcomes and Measures: The primary outcomes were all-cause mortality, recurrent VTE, and major bleeding. Event rates and 95% CIs were calculated and expressed per 100 person-years. Hazard ratios (HRs) were estimated with Cox proportional hazards regression models and adjusted for relevant confounding variables. All-cause mortality was considered a competing risk for other clinical outcomes in the estimation of cumulative incidences. Results: Of the 10 684 patients with objectively confirmed VTE, serum creatinine data were available for 8979 patients (84.0%). Of those, 4432 patients (49.4%) were female and 5912 patients (65.8%) were White; 6924 patients (77.1%; median age, 57 years; interquartile range [IQR], 44-69 years) were classified as having mild to no CKD, and 2055 patients (22.9%; median age, 70 years; IQR, 59-78 years) were classified as having moderate to severe CKD. Calculations using the equation from the Modification of Diet in Renal Disease study indicated that, among the 6924 patients with mild to no CKD, 2991 patients had stage 1 CKD, and 3933 patients had stage 2 CKD; among the 2055 patients with moderate to severe CKD, 1650 patients had stage 3 CKD, 190 patients had stage 4 CKD, and 215 patients had stage 5 CKD. The distribution of VTE presentation was comparable between groups. In total, 1171 patients (57.0%) with moderate to severe CKD and 4079 patients (58.9%) with mild to no CKD presented with deep vein thrombosis alone, 547 patients (26.6%) with moderate to severe CKD and 1723 patients (24.9%) with mild to no CKD presented with pulmonary embolism alone, and 337 patients (16.4%) with moderate to severe CKD and 1122 patients (16.2%) with mild to no CKD presented with both pulmonary embolism and deep vein thrombosis. Compared with patients with mild to no CKD, patients with moderate to severe CKD were more likely to be female (3259 women [47.1%] vs 1173 women [57.1%]) and older than 65 years (2313 patients [33.4%] vs 1278 patients [62.2%]). At baseline, the receipt of parenteral therapy alone was comparable between the 2 groups (355 patients [17.3%] with moderate to severe CKD vs 1253 patients [18.1%] with mild to no CKD). Patients with moderate to severe CKD compared with those with mild to no CKD were less likely to be receiving direct oral anticoagulant therapy, either alone (557 patients [27.1%] vs 2139 patients [30.9%]) or in combination with parenteral therapy (319 patients [15.5%] vs 1239 patients [17.9%]). Patients with moderate to severe CKD had a higher risk of all-cause mortality (adjusted hazard ratio [aHR], 1.44; 95% CI, 1.21-1.73), major bleeding (aHR, 1.40; 95% CI, 1.03-1.90), and recurrent VTE (aHR, 1.40; 95% CI, 1.10-1.77) than patients with mild to no CKD. Conclusions and Relevance: In this study of patients with VTE, the presence of moderate to severe CKD was associated with increases in the risk of death, VTE recurrence, and major bleeding compared with the presence of mild to no CKD

Perioperative Bridging Anticoagulation in Patients with Atrial Fibrillation

BACKGROUND: It is uncertain whether bridging anticoagulation is necessary for patients with atrial fibrillation who need an interruption in warfarin treatment for an elective operation or other elective invasive procedure. We hypothesized that forgoing bridging anticoagulation would be noninferior to bridging with low-molecular-weight heparin for the prevention of perioperative arterial thromboembolism and would be superior to bridging with respect to major bleeding. METHODS: We performed a randomized, double-blind, placebo-controlled trial in which, after perioperative interruption of warfarin therapy, patients were randomly assigned to receive bridging anticoagulation therapy with low-molecular-weight heparin (100 IU of dalteparin per kilogram of body weight) or matching placebo administered subcutaneously twice daily, from 3 days before the procedure until 24 hours before the procedure and then for 5 to 10 days after the procedure. Warfarin treatment was stopped 5 days before the procedure and was resumed within 24 hours after the procedure. Follow-up of patients continued for 30 days after the procedure. The primary outcomes were arterial thromboembolism (stroke, systemic embolism, or transient ischemic attack) and major bleeding. RESULTS: In total, 1884 patients were enrolled, with 950 assigned to receive no bridging therapy and 934 assigned to receive bridging therapy. The incidence of arterial thromboembolism was 0.4% in the no-bridging group and 0.3% in the bridging group (risk difference, 0.1 percentage points; 95% confidence interval [CI], -0.6 to 0.8; P=0.01 for noninferiority). The incidence of major bleeding was 1.3% in the no-bridging group and 3.2% in the bridging group (relative risk, 0.41; 95% CI, 0.20 to 0.78; P=0.005 for superiority). CONCLUSIONS: In patients with atrial fibrillation who had warfarin treatment interrupted for an elective operation or other elective invasive procedure, forgoing bridging anticoagulation was noninferior to perioperative bridging with low-molecular-weight heparin for the prevention of arterial thromboembolism and decreased the risk of major bleeding. (Funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health; BRIDGE ClinicalTrials.gov number, NCT00786474.)

An assessment of phytoplankton primary productivity in the Arctic Ocean from satellite ocean color/in situ chlorophyll-a based models

We investigated 32 net primary productivity (NPP) models by assessing skills to reproduce integrated NPP in the Arctic Ocean. The models were provided with two sources each of surface chlorophyll-a concentration (chlorophyll), photosynthetically available radiation (PAR), sea surface temperature (SST), and mixed-layer depth (MLD). The models were most sensitive to uncertainties in surface chlorophyll, generally performing better with in situ chlorophyll than with satellite-derived values. They were much less sensitive to uncertainties in PAR, SST, and MLD, possibly due to relatively narrow ranges of input data and/or relatively little difference between input data sources. Regardless of type or complexity, most of the models were not able to fully reproduce the variability of in situ NPP, whereas some of them exhibited almost no bias (i.e., reproduced the mean of in situ NPP). The models performed relatively well in low-productivity seasons as well as in sea ice-covered/deep-water regions. Depth-resolved models correlated more with in situ NPP than other model types, but had a greater tendency to overestimate mean NPP whereas absorption-based models exhibited the lowest bias associated with weaker correlation. The models performed better when a subsurface chlorophyll-a maximum (SCM) was absent. As a group, the models overestimated mean NPP, however this was partly offset by some models underestimating NPP when a SCM was present. Our study suggests that NPP models need to be carefully tuned for the Arctic Ocean because most of the models performing relatively well were those that used Arctic-relevant parameters

International trends in clinical characteristics and oral anticoagulation treatment for patients with atrial fibrillation: Results from the GARFIELD-AF, ORBIT-AF I, and ORBIT-AF II registries.

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the world. We aimed to provide comprehensive data on international patterns of AF stroke prevention treatment. METHODS: Demographics, comorbidities, and stroke risk of the patients in the GARFIELD-AF (n=51,270), ORBIT-AF I (n=10,132), and ORBIT-AF II (n=11,602) registries were compared (overall N=73,004 from 35 countries). Stroke prevention therapies were assessed among patients with new-onset AF (≤6 weeks). RESULTS: Patients from GARFIELD-AF were less likely to be white (63% vs 89% for ORBIT-AF I and 86% for ORBIT-AF II) or have coronary artery disease (19% vs 36% and 27%), but had similar stroke risk (85% CHA2DS2-VASc ≥2 vs 91% and 85%) and lower bleeding risk (11% with HAS-BLED ≥3 vs 24% and 15%). Oral anticoagulant use was 46% and 57% for patients with a CHA2DS2-VASc=0 and 69% and 87% for CHA2DS2-VASc ≥2 in GARFIELD-AF and ORBIT-AF II, respectively, but with substantial geographic heterogeneity in use of oral anticoagulant (range: 31%-93% [GARFIELD-AF] and 66%-100% [ORBIT-AF II]). Among patients with new-onset AF, non-vitamin K antagonist oral anticoagulant use increased over time to 43% in 2016 for GARFIELD-AF and 71% for ORBIT-AF II, whereas use of antiplatelet monotherapy decreased from 36% to 17% (GARFIELD-AF) and 18% to 8% (ORBIT-AF I and II). CONCLUSIONS: Among new-onset AF patients, non-vitamin K antagonist oral anticoagulant use has increased and antiplatelet monotherapy has decreased. However, anticoagulation is used frequently in low-risk patients and inconsistently in those at high risk of stroke. Significant geographic variability in anticoagulation persists and represents an opportunity for improvement

Edoxaban: an update on the new oral direct factor Xa inhibitor.

Edoxaban is a once-daily oral anticoagulant that rapidly and selectively inhibits factor Xa in a concentration-dependent manner. This review describes the extensive clinical development program of edoxaban, including phase III studies in patients with non-valvular atrial fibrillation (NVAF) and symptomatic venous thromboembolism (VTE). The ENGAGE AF-TIMI 48 study (N = 21,105; mean CHADS2 score 2.8) compared edoxaban 60 mg once daily (high-dose regimen) and edoxaban 30 mg once daily (low-dose regimen) with dose-adjusted warfarin [international normalized ratio (INR) 2.0-3.0] and found that both regimens were non-inferior to warfarin in the prevention of stroke and systemic embolism in patients with NVAF. Both edoxaban regimens also provided significant reductions in the risk of hemorrhagic stroke, cardiovascular mortality, major bleeding and intracranial bleeding. The Hokusai-VTE study (N = 8,292) in patients with symptomatic VTE had a flexible treatment duration of 3-12 months and found that following initial heparin, edoxaban 60 mg once daily was non-inferior to dose-adjusted warfarin (INR 2.0-3.0) for the prevention of recurrent VTE, and also had a significantly lower risk of bleeding events. Both studies randomized patients at moderate-to-high risk of thromboembolic events and were further designed to simulate routine clinical practice as much as possible, with edoxaban dose reduction (halving dose) at randomisation or during the study if required, a frequently monitored and well-controlled warfarin group, a well-monitored transition period at study end and a flexible treatment duration in Hokusai-VTE. Given the phase III results obtained, once-daily edoxaban may soon be a key addition to the range of antithrombotic treatment options