Evaluating post-processing approaches for monthly and seasonal streamflow forecasts

Streamflow forecasting is prone to substantial uncertainty due to errors in meteorological forecasts, hydrological model structure, and parameterization, as well as in the observed rainfall and streamflow data used to calibrate the models. Statistical streamflow post-processing is an important technique available to improve the probabilistic properties of the forecasts. This study evaluates post-processing approaches based on three transformations – logarithmic (Log), log-sinh (Log-Sinh), and Box–Cox with λ=0.2 (BC0.2) – and identifies the best-performing scheme for post-processing monthly and seasonal (3-months-ahead) streamflow forecasts, such as those produced by the Australian Bureau of Meteorology. Using the Bureau's operational dynamic streamflow forecasting system, we carry out comprehensive analysis of the three post-processing schemes across 300 Australian catchments with a wide range of hydro-climatic conditions. Forecast verification is assessed using reliability and sharpness metrics, as well as the Continuous Ranked Probability Skill Score (CRPSS). Results show that the uncorrected forecasts (i.e. without post-processing) are unreliable at half of the catchments. Post-processing of forecasts substantially improves reliability, with more than 90 % of forecasts classified as reliable. In terms of sharpness, the BC0.2 scheme substantially outperforms the Log and Log-Sinh schemes. Overall, the BC0.2 scheme achieves reliable and sharper-than-climatology forecasts at a larger number of catchments than the Log and Log-Sinh schemes. The improvements in forecast reliability and sharpness achieved using the BC0.2 post-processing scheme will help water managers and users of the forecasting service make better-informed decisions in planning and management of water resources.Fitsum Woldemeskel, David McInerney, Julien Lerat, Mark Thyer, Dmitri Kavetski, Daehyok Shin, Narendra Tuteja and George Kuczer

Direct susceptibility testing for multi drug resistant tuberculosis: A meta-analysis

<p>Abstract</p> <p>Background</p> <p>One of the challenges facing the tuberculosis (TB) control programmes in resource-limited settings is lack of rapid techniques for detection of drug resistant TB, particularly multi drug resistant tuberculosis (MDR TB). Results obtained with the conventional indirect susceptibility testing methods come too late to influence a timely decision on patient management. More rapid tests directly applied on sputum samples are needed. This study compared the sensitivity, specificity and time to results of four direct drug susceptibility testing tests with the conventional indirect testing for detection of resistance to rifampicin and isoniazid in <it>M. tuberculosis</it>. The four direct tests included two in-house phenotypic assays – Nitrate Reductase Assay (NRA) and Microscopic Observation Drug Susceptibility (MODS), and two commercially available tests – Genotype^®MTBDR and Genotype^®MTBDR<it>plus </it>(Hain Life Sciences, Nehren, Germany).</p> <p>Methods</p> <p>A literature review and meta-analysis of study reports was performed. The Meta-Disc software was used to analyse the reports and tests for sensitivity, specificity, and area under the summary receiver operating characteristic (sROC) curves. Heterogeneity in accuracy estimates was tested with the Spearman correlation coefficient and Chi-square.</p> <p>Results</p> <p>Eighteen direct DST reports were analysed: NRA – 4, MODS- 6, Genotype MTBDR^®– 3 and Genotype^®MTBDR<it>plus </it>– 5. The pooled sensitivity and specificity for detection of resistance to rifampicin were 99% and 100% with NRA, 96% and 96% with MODS, 99% and 98% with Genotype^®MTBDR, and 99% and 99% with the new Genotype^®MTBDR<it>plus</it>, respectively. For isoniazid it was 94% and 100% for NRA, 92% and 96% for MODS, 71% and 100% for Genotype^®MTBDR, and 96% and 100% with the Genotype^®MTBDR<it>plus</it>, respectively. The area under the summary receiver operating characteristic (sROC) curves was in ranges of 0.98 to 1.00 for all the four tests. Molecular tests were completed in 1 – 2 days and also the phenotypic assays were much more rapid than conventional testing.</p> <p>Conclusion</p> <p>Direct testing of rifampicin and isoniazid resistance in <it>M. tuberculosis </it>was found to be highly sensitive and specific, and allows prompt detection of MDR TB.</p

Pulmonary adenomatosis and maedi-visna in Ethiopian central highland sheep: a microscopic study

M. Tibbo is ILRI authorMicroscopic examination of pneumonic lungs of the Ethiopian highland sheep (n = 35) was made and compared with the pneumonic lungs from ten sheep and 66 goats from the lowlands. Lesions compatible with sheep pulmonary adenomatosis (SPA; 8/35, 22.8%), and maedi-visna (MV; 9/35, 25.7%) were recorded only in sheep from the central highlands. Interstitial pneumonia (43.2%), bronchopneumonia (35.1%), and verminous pneumonia (6.3%) were recorded in both sheep and goats from the high- and the lowlands. SPA was documented for the first time in sheep from Ethiopia in this report. We believe that MV and SPA were introduced into Ethiopia through importation of exotic sheep. These infections should be considered in dealing with the diagnosis of respiratory diseases in all the sheep breeds in the central highlands and in the exotic and the crossbred sheep in the other parts of the country

Complex networks for streamflow dynamics

Streamflow modeling is an enormously challenging problem, due to the complex and nonlinear interactions between climate inputs and landscape characteristics over a wide range of spatial and temporal scales. A basic idea in streamflow studies is to establish connections that generally exist, but attempts to identify such connections are largely dictated by the problem at hand and the system components in place. While numerous approaches have been proposed in the literature, our understanding of these connections remains far from adequate. The present study introduces the theory of networks, in particular complex networks, to examine the connections in streamflow dynamics, with a particular focus on spatial connections. Monthly streamflow data observed over a period of 52 years from a large network of 639 monitoring stations in the contiguous US are studied. The connections in this streamflow network are examined primarily using the concept of clustering coefficient, which is a measure of local density and quantifies the network's tendency to cluster. The clustering coefficient analysis is performed with several different threshold levels, which are based on correlations in streamflow data between the stations. The clustering coefficient values of the 639 stations are used to obtain important information about the connections in the network and their extent, similarity, and differences between stations/regions, and the influence of thresholds. The relationship of the clustering coefficient with the number of links/actual links in the network and the number of neighbors is also addressed. The results clearly indicate the usefulness of the network-based approach for examining connections in streamflow, with important implications for interpolation and extrapolation, classification of catchments, and predictions in ungaged basins

Ki-67 protein expression and tumor associated inflammatory cells (macrophages and mast cells) in canine colorectal carcinoma

Abstract Background Ki67 index, tumor associated macrophages (TAMs) and mast cells (MCs) are associated with malignancies in animal and human neoplasms including colorectal carcinomas (CRC). This has not been assessed in canine CRC. Given similar genetic abnormalities between human and canine CRC, we assessed Ki-67 and mitotic indices, TAMs and MC count (MCC) in canine CRC (n = 17). TAMs and MCC were compared with those in adenomas (n = 13) and control (n = 9). Results Ki-67 index in CRC (17.13 ± 11.50) was strongly correlated (r = 0.98, p  0.05). Conclusion Ki-67 index, TAMs and MCC in canine CRC were recorded for the first time in this study. Ki-67 index and MCC are associated with malignancy in canine CRC. Quantitative assessment of MCs and Ki-67 coupled with mitotic index and other clinical parameters may help in evaluating malignancy in canine CRC. TAMs likely play a role in the development of canine colorectal tumors. Further studies to determine the clinical significance of these parameters for prognostic, chemo-preventive and chemotherapeutic purposes in canine colorectal tumors are recommended

Nonlinear analysis of rainfall variability

Abstract This study examines the utility of nonlinear dynamic concepts for analysis of rainfall variability across Western Australia. The correlation dimension method, which involves data reconstruction and nearest neighbor concepts, is employed to estimate the dimensionality of rainfall time series and assess the degree of variability (or complexity) of rainfall dynamics. Monthly rainfall data observed over a period of 67 years (January 1937-December 2003) from each of 62 raingage stations across Western Australia are analyzed. The results indicate the utility of the dimensionality concept for identification of rainfall variability at point locations and rainfall patterns across space. The dimension estimates (ranging from 4.63 to 8.29) suggest a medium-level complexity in rainfall dynamics at each of the 62 stations and, hence, across Western Australia. Rainfall dynamics are generally more complex in the southwest part of Western Australia than in other parts of the state, with the far south exhibiting a greater complexity. Also, the mid-western region exhibits slightly more complex rainfall dynamics when compared to the northeast. The reliability of the correlation dimension estimates with respect to data size (i.e. number of data points in time series) is also discussed. The outcomes of the present study, the first ever based on nonlinear dynamic and chaos theories for rainfall in Australia and also across a far more extensive network of raingages, can provide new avenues for rainfall (and other hydrologic) studies in Australia and for spatial/spatio-temporal analysis

Serum enzyme levels and influencing factors in three indigenous Ethiopian sheep breeds

Serum enzymes were studied in 377 apparently healthy sheep from three indigenous sheep breeds of Ethiopia. The effect of breed, age, sex and season on alanine aminotransferase (ALT)/glutamic pyruvic transaminase (GPT), aspartate aminotransferase (AST)/glutamic oxalacetic transaminase (GOT), alkaline phosphatase (ALP) and acid phosphatase (AcP) levels was assessed. The mean serum enzymes levels of the indigenous Menz, Tukur and Wello sheep breeds ranged from 17.2-17.7 IU l-1, AST/GOT from 50.4-56.6 IU l-1, ALP from 93.2-103.9 IU l-1, and AcP from 2.47-2.56 IU l-1, were within the normal range for sheep elsewhere. Season had significant influence on all serum enzymes except for the AcP in Menz breed. Sex had significant effect on AST/GOT for Menz and on ALP for all sheep breeds, with consistently higher values in males than in females. Age was significant only on ALP in the Menz and Tukur breeds. The serum enzyme levels of these indigenous sheep breeds can be used as normal reference values for Ethiopian sheep breeds adapted to similar agro-ecology and production system

Risk factors for mortality associated with respiratory disease among Menz and Horro sheep in Ethiopia

A retrospective case-control study was conducted on 6718 sheep of two breeds (2772 Horro and 3946 Menz) on risk factors for mortality associated with respiratory disease (MARD) in Ethiopia, based on data collected between October 1993 and December 1997. Potential risk factors examined were breed, gender, age, month, and air temperatures. Fifty-four per cent of total deaths in the flock could be attributed to respiratory disease and the annual MARD rate ranged between 6.3 and 19.0%. There was significant breed (P<0.0001) and gender (P<0.0001) difference in MARD. The Horro breed had a higher (P<0.0001) annual MARD than the Menz breed (16.5±0.18 vs. 12.4±0.15%). A higher (P<0.0001) proportion of males suffered than females (15.1±0.23% vs. 13.8±0.13%). Age was also an important risk factor for MARD: there was a strong polynomial relationship (R2=0.91, P<0.0001) between MARD and age; the risk of being young if a sheep was a MARD case was high. MARD was high between October and March but relatively low between the months of April and September. There was a significant (P<0.05) negative cubic relationship (R2=0.49) between monthly MARD and monthly average minimum air temperatures. There was also a significant (P<0.01) positive exponential relationship (R2=0.61) between monthly MARD and average monthly daily deviation between maximum and minimum air temperatures. Timely health and management interventions focusing on these factors are necessary to alleviate losses from MARD. Understanding variations in MARD risk within a population can enhance early response to potential outbreaks, reducing losses