Spatiosurvival analysis of mortality on smallholder dairy farms in Tanga and Iringa regions of Tanzania

A combination of survival and spatial analyses was applied to a dataset containing cattle mortalities on smallholder dairy farms in two separate regions (Tanga and Iringa) of Tanzania. Cattle mortality data for the year 1998 were collected retrospectively during the period January to April 1999. The objectives of the current study were, firstly, to quantify the hazard of mortality and, secondly, to investigate whether there was a spatial pattern in the variation that was unaccounted for in the hazard of mortality. A Cox regression model with farm as a frailty term was used to quantify the hazard of mortality. Geostatistical techniques were used to explore the first- and second-order spatial distribution of the farm frailty term. A total of 1,790 cattle from 400 randomly sampled smallholder dairy farms were included in the study. The overall mortality incidence rate for the study was 11.8 per 100 animal years (95% CI 10.0–13.8). The hazard of mortality for male cattle was 2.4 (95% CI 1.7–3.4) times higher than that of female cattle. There was evidence of a first-order spatial pattern, i.e., a tendency for farms with higher frailty to aggregate.     

Rapid spectroscopic separation of three Canadian softwoods

Near Infrared (NIR) and Fluorescence (FS) spectroscopy were investigated for their ability to rapidly separate three Canadian softwoods: balsam fir, western hemlock, and white spruce. NIR and FS spectral data were used to develop classification models using soft independent modeling of class analogies (SIMCA) method. For each wood species, spectra of 90 wood specimens were collected over a wavelength window of 800–2,500?nm for NIR spectral data and a wavelength range of 380–540 and 380–705?nm for FS spectral data. Raw spectra and first-derivative-transformed spectra were used to develop NIR calibration models to separate the three wood species using the wavelength ranges, 800–2,500, 1,100–2,200, and 1,300–2,000?nm, by the SIMCA method. Similarly, FS raw spectral data were also used to develop FS calibrations using wavelength ranges of 380–540 and 380–705?nm. Principal component analysis models were made for each class from the calibration set consisting of 65 specimens of each of the three wood species. Specimens not present in the calibration set (27 specimens of each wood species) were tested for classification according to the SIMCA method at a 5 and 25% significance level. Type I error associated with the models developed with NIR spectral data ranged from 0 to 19 and 0 to 52% for the 5 and 25% significance levels, respectively, while type II error ranged from 2 to 50 and 0 to 19%, respectively. When tested at a 5% significance level, there was no significant improvement in NIR models developed with first-derivative-transformed spectra over models developed with raw spectra. Type I error associated with the models developed with Fluorescence spectral data ranged from 0 to 4 and 7 to 30% for the 5 and 25% significance levels, respectively, while type II error ranged from 1 to 9 and 0 to 1%, respectively. There were no significant differences in performance of FS models developed with spectra using wavelength ranges of 380–540 and 380–705?nm.     

Bacterial wilt and canker of tomato: fundamentals of a complex biological system

Tomato (Solanum lycopersicum) is well-known as a model for study of plant–pathogen interactions, since it is a crop of global relevance and susceptible to multiple bacterial, fungal, viral and nematode pathogens. Among bacterial phytopathogens, the actinomycete Clavibacter michiganensis subsp. michiganensis (Cmm) is the causal agent of bacterial wilt and canker of tomato, considered a quarantine disease at international level. The tomato–Cmm interaction has been studied to decipher the pathogenicity mechanisms in Cmm, susceptibility mechanisms in tomato, molecular basis of resistance to Cmm in wild species relative to domesticated tomato, and the level of genetic variability in Cmm. The objective of this review is to discuss recent advances in tomato–Cmm compatible interaction, which can be integrated for application in early diagnosis and biological control of bacterial wilt and canker of tomato. Further study of plant–microorganism interactions is a promising field for improvements in tomato pathogen resistance.     

Screening of sorghum genotypes for resistance to Striga hermonthica and S. asiatica and compatibility with Fusarium oxysporum f.sp. strigae

In the semi-arid areas of Tanzania, yield losses of sorghum [Sorghum biocolor (L.) Moench] due to Striga hermonthica (Sh) and S. asiatica (Sa) infestations are estimated to be 30–90%. The use of resistant sorghum varieties compatible with Fusarium oxysporum f.sp. strigae (FOS), a biocontrol agent of Striga, may supress the weed and enhance the crop productivity. The objective of this study was to screen and select farmer-preferred sorghum genotypes for Sh and Sa resistance and FOS compatibility for resistance breeding under Tanzanian conditions. Sixty sorghum genotypes were evaluated under screen house conditions using Sh- and Sa-infested field soils with controlled seed infestation, with or without inoculation of the sorghum seeds with FOS. Inoculation of sorghum seeds with FOS significantly enhanced sorghum growth and productivity, and supressed Sh and Sa growth and development. There were reductions of 1–4 Sh and Sa plants when sorghum seeds were inoculated with FOS. Overall, we selected 25 promising sorghum lines resistant to Sh and/or Sa, and with FOS compatibility. The selected sorghum lines are valuable genetic resources for the development of Striga management in sorghum through the integrated use of host resistance and FOS inoculation.     

Tartaric acid catalyzed furfurylation of beech wood

European beech (Fagus sylvatica L.) is a major tree species of European forest which is underexploited because of its low dimensional stability and durability. Similarly to what has been developed with radiata pine, furfurylation might be the answer to optimize the utilization of local beech wood. Beech wood furfurylation process was studied using five different catalysts: maleic anhydride, maleic acid, citric acid, itaconic acid, and tartaric acid. Optimization of the furfurylation process was investigated for different catalyst and furfuryl alcohol (FA) contents, and different duration of polymerization. The following properties were studied: weight percent gain (WPG), leachability, anti-swelling efficiency (ASE), wettability, modulus of elasticity, modulus of rupture, Brinell hardness, and decay durability. Tartaric acid, never investigated up to now, was retained as catalyst to perform furfurylation due to its efficacy compared to other catalysts and its novelty. Wood modification with FA and tartaric acid as catalyst led to samples with high WPG even after leaching, improved ASE, and lower wettability with water. Increasing the polymerization duration increased the fixation of FA in treated wood. Most of all, treatment gave a significant improvement in mechanical properties and resistance to wood decaying fungi.     

Rice straw biochar affects water retention and air movement in a sand-textured tropical soil

Despite the current global attention on biochar (BC) as a soil amendment, knowledge is limited on how BC impacts the physical properties of coarse-textured soils (sand > 95%), particularly in tropical regions. A two-season field-study was conducted to investigate the effect of rice straw BC (3% w/w) on water retention, gas transport and structure of a sand-textured tropical soil. We sampled 3 months and 15 months after BC application and measured wet- and dry-region soil water retention, air permeability and gas diffusivity at selected matric potentials. At all measured potentials and for both sampling times, soil water retention was significantly higher (20–150%) for the BC treatment due to increased fraction of smaller pores (< 30 µm) at the expense of macropores (< 100 µm). Although there was no consistent effect of BC on air-filled porosity, BC significantly reduced air permeability and gas diffusivity (~20%) at ?30 kPa matric potential. After 15-months, air permeability decreased by ~15% after BC amendment, but analyses of the pore structure revealed a more tortuous and complex soil structure. Thus, application of rice straw BC to similar coarse-textured soils will improve soil-water relations and over time provide better structure for agricultural purposes.     

Growth,feed utilization,and liver histology of juvenile Nile tilapia (Oreochromis niloticus) fed diets containing increasing levels of swine fat

Due to predictions that the expanding aquaculture sector cannot continue to rely on finite marine stocks for fish oil, there have been several research works within the aquafeed industry to find sustainable alternatives for dietary lipid sources. This study was conducted to evaluate the effects of a range of inclusion levels of rendered swine fat on the growth performance and liver histology of juvenile Nile tilapia, Oreochromis niloticus. Fish (initial weight ~ 20 g) were randomly stocked into twelve 1 m³ nylon mesh hapas and fed isoenergetic and isonitrogenous diets containing rendered swine fat at varying inclusion levels of 0% (Control), 5% (SF5), 7% (SF7), or 10% (SF10) for 84 days. The control diet contained 5% fish oil as the lipid source. At the end of the trial, there were no significant differences between the final weights of the fish that were fed the control (38.01 ± 0.76) and SF5 diets (37.85 ± 0.68), and both groups recorded significantly higher (P < 0.05) specific growth rates relative to the SF7 and SF10 groups. Specific growth rates ranged from 0.59% day^?1 (SF10) to 0.75% day^?1 (Control and SF5). The fish that were fed the SF7 and SF10 diets had significantly (P < 0.05) larger livers relative to the control and SF5 fish. Histological examination further revealed significant liver alterations in the SF7 and SF10 fish, as evidenced by hepatocyte nuclei migration, hepatic vacuolation, and varying degrees of steatosis. Calculations of profit indices showed that the SF5 diet offers the best economic viability, taking into consideration both the monetary values of fish produced and cost of feed fed over the trial period. The results of this study indicate that rendered swine as a sole lipid source in juvenile Nile tilapia diets can be included at 5% without depressing fish growth.     

The socioeconomic benefits of biological control of western corn rootworm Diabrotica virgifera virgifera and wireworms Agriotes spp. in maize and potatoes for selected European countries

Journal of Plant Diseases and Protection - Innovative biological pest control of the western corn rootworm (WCR) Diabrotica virgifera virgifera and wireworms Agriotes spp. in maize and potato...     

Maize meal fortification is associated with improved vitamin A and iron status in adolescents and reduced childhood anaemia in a food aid-dependent refugee population

OBJECTIVE: To assess changes in the Fe and vitamin A status of the population of Nangweshi refugee camp associated with the introduction of maize meal fortification. DESIGN: Pre- and post-intervention study using a longitudinal cohort. SETTING: Nangweshi refugee camp, Zambia. SUBJECTS: Two hundred and twelve adolescents (10-19 years), 157 children (6-59 months) and 118 women (20-49 years) were selected at random by household survey in July 2003 and followed up after 12 months. RESULTS: Maize grain was milled and fortified in two custom-designed mills installed at a central location in the camp and a daily ration of 400 g per person was distributed twice monthly to households as part of the routine food aid ration. During the intervention period mean Hb increased in children (0.87 g/dl; P < 0.001) and adolescents (0.24 g/dl; P = 0.043) but did not increase in women. Anaemia decreased in children by 23.4% (P < 0.001) but there was no significant change in adolescents or women. Serum transferrin receptor (log10-transformed) decreased by -0.082 microg/ml (P = 0.036) indicating an improvement in the Fe status of adolescents but there was no significant decrease in the prevalence of deficiency (-8.5%; P = 0.079). In adolescents, serum retinol increased by 0.16 micromol/l (P < 0.001) and vitamin A deficiency decreased by 26.1% (P < 0.001). CONCLUSIONS: The introduction of fortified maize meal led to a decrease in anaemia in children and a decrease in vitamin A deficiency in adolescents. Centralised, camp-level milling and fortification of maize meal is a feasible and pertinent intervention in food aid operations.