Protostrongylid infection in meat sheep from Northwestern Spain: prevalence and risk factors

2093 Faecal samples from 74 commercial meat ovine flocks were collected and examined by the Baermann-Wetzel method for protostrongylid infection. The risk of being infected by lungworms was evaluated with a data mining classification tree (CHAID), and the intensity of infection with a general linear model (GLM). 242 out of 2093 faecal samples examined were positive for protostrongylid infection (11.6%; 95% CI 10.2-12.9). Only two species were found, Muellerius capillaris (97.9%) and Neostrongylus linearis (5.4%). 50 out of 74 farms presented at least one animal shedding protostrongylid larvae in faeces. All of them held animals infected by M. capillaris and seven presented mixed infections with N. linearis. Average larval output in infected sheep was 11.9 (SD 30.91). This study showed that protostrongylid prevalence in sheep for meat production was determined mainly by a positive interaction with Dictyocaulus filaria infection; other factors that have influenced over protostrongylid infection were age, introducing external animals in the flocks, mixed management with goats and animal density in pastures. Treatment effects on prevalence were only observed in flocks that did not introduce ewes. The lowest protostrongylid prevalence has been reported in flocks without D. filaria infection and without contact with goats.     

Detection of mistletoe infected trees using UAV high spatial resolution images

Journal of Plant Diseases and Protection - Remote detection of aerial parasitic plants in forests is imperative in precision forestry, as it can help to manage tree stands and to monitor forest...     

Seasonal soil nitrogen dynamics affect yields of lowland rice in the savanna zone of West Africa

Background : Rice production in low‐input systems of West Africa relies largely on nitrogen supply from the soil. Especially in the dry savanna agro‐ecological zone, soil organic N is mineralized during the transition period between the dry and the wet seasons. In addition, in the inland valley landscape, soil N that is mineralized on slopes may be translocated as nitrate into the lowlands. There, both in‐situ mineralized as well as the laterally translocated nitrate‐N will be exposed to anaerobic conditions and is thus prone to losses. Aim : We determined the dynamics of soil NO₃‐N along a valley toposequence during the dry‐to‐wet season transition period and the effects of soil N‐conserving production strategies on the grain yield of rainfed lowland rice grown during the subsequent wet season. Methods : Field experiments in Dano (Burkina Faso) assessed during two consecutive years the temporal dynamics and spatial fluxes of soil nitrate along a toposequence. We applied sequential and depth‐stratified soil nitrate analysis and nitrate absorption in ion exchange resin capsules in lowlands that were open to subsurface interflow and in those where the interflow from the was intercepted. During one year only we also assessed the effect of pre‐rice vegetation on conserving this NO₃‐N as well as on N addition by biological N₂ fixation in legumes using δ¹⁵N isotope dilution. Finally, we determined the impact of soil N fluxes and their differential management during the transition season on growth, yield and N use of rainfed lowland rice. Results : Following the first rainfall event of the season, soil NO₃‐N initially accumulated and subsequently decreased gradually in the soil of the valley slope. Much of this nitrate N was translocated by lateral sub‐surface flow into the valley bottom wetland. There, pre‐rice vegetation was able to absorb much of the in‐situ mineralized and the laterally‐translocated soil NO₃‐N, reducing its accumulation in the soil from 40–43 kg N ha^?1 under a bare fallow to 1–23 kg N ha^?1 in soils covered by vegetation. Nitrogen accumulation in the biomass of the transition season crops ranged from 44 to 79 kg N ha^?1 with a 36–39% contribution from biological N₂ fixation in the case of legumes. Rice agronomic performance improved following the incorporation as green manure of this “nitrate catching” vegetation, with yields increasing up to 3.5 t ha^?1 with N₂‐fixing transition seasons crops. Conclusion : Thus, integrating transition season legumes during the pre‐rice cropping niche in the prevailing low‐input systems in inland valleys of the dry savanna zone of West Africa can temporarily conserve substantial amounts of soil NO₃‐N. It can also add biologically‐fixed N, thus contributing to increase rice yields in the short‐term and, in the long‐term, possibly maintaining or improving soil fertility in the lowland.     

巴西里贝拉山谷的秘密

巴西的园艺业有一个鲜为人知的秘密：在圣保罗州（Saoaul）南端的几个城镇,集中了约323家观赏花卉种植者,其栽培总面积达800公顷,这几个城镇已成为圣保罗州花卉种植的主要地区。该地区位于里贝拉河与大西洋交汇的低洼处,有着特别的微气候,年均温度在24℃,相对湿度85％,犹如天然温室一样。     

Comparative measurements of transpiration and canopy conductance in two mixed deciduous woodlands differing in structure and species composition

Transpiration of two heterogeneous broad-leaved woodlands in southern England was monitored by the sap flux technique throughout the 2006 growing season. Grimsbury Wood, which had a leaf area index (LAI) of 3.9, was dominated by oak (Quercus robur L.) and birch (Betula pubescens L.) and had a continuous hazel (Corylus avellana L.) understory. Wytham Woods, which had an LAI of 3.6, was dominated by ash (Fraxinus excelsior L.) and sycamore (Acer pseudoplatanus L.) and had only a sparse understory. Annual canopy transpiration was 367 mm for Grimsbury Wood and 397 mm for Wytham Woods. These values were similar to those for beech (Fagus sylvatica L.) plantations in the same region, and differ from one another by less than the typical margin of uncertainty of the sap flux technique. Canopy conductance (g(c)), calculated for both woodlands by inverting the Penman-Monteith equation, was related to incoming solar radiation (R(G)) and the vapor pressure deficit (D). The response of g(c) to R(G) was similar for both forests. Both reference conductance (g(cref)), defined as g(c) at D=1 kPa, and stomatal sensitivity (-m), defined as the slope of the logarithmic response curve of g(c) to D, increased during the growing season at Wytham Woods but not at Grimsbury Wood. The -m/g(cref) ratio was significantly lower at Wytham Woods than at Grimsbury Wood and was insufficient to keep the difference between leaf and soil water potentials constant, according to a simple hydraulic model. This meant that annual water consumption of the two woodlands was similar despite different regulatory mechanisms and associated short-term variations in canopy transpiration. The -m/g(cref) ratio depended on the range of D under which the measurements were made. This was shown to be particularly important for studies conducted under low and narrow ranges of D.     

Seasonal and interannual variability of canopy transpiration of a hedgerow in southern England

Transpiration from a hawthorn (Crataegus monogyna L.) dominated hedgerow in southern England was measured continuously over two growing seasons by the sap flow technique. Accompanying measurements of structural parameters, microclimate and leaf stomatal and boundary layer conductances were used to establish the driving factors of hedgerow transpiration. Observed transpiration rates, reaching peak values of around 8 mm day(-1) and a seasonal mean of about 3.5 mm day(-1), were higher than those reported for most other temperate deciduous woodlands, except short-rotation coppice and wet woodlands. The high rates were caused by the structural and physiological characteristics of hawthorn leaves, which exhibited much higher stomatal and boundary-layer conductances than those of the second-most abundant woody species in the hedgerow, field maple (Acer campestre L.). Only in the hot summer of 2003 did stomatal conductance, and thus transpiration, decrease substantially. The hedgerow canopy was always closely coupled to the atmosphere. Hedgerow transpiration equaled potential evaporation (calculated by the Priestley-Taylor formula) in 2003 and exceeded it in 2004, which meant that a substantial fraction of the energy (21% in 2003 and more than 37% in 2004) came from advection. Hedgerow canopy conductance (g(c)), as inferred from the sap flow data by inverting the Penman-Monteith equation, responded to solar radiation (R(G)) and vapor pressure deficit (D). Although the response to R(G) showed no systematic temporal variation, the response to D, described as g(c)(D) = g(cref) - mln(D), changed seasonally. The reference g(c) depended on leaf area index and the ratio of -m/g(cref) on long-term mean daytime D. A model is proposed based on these observations that predicts canopy conductance for the hawthorn hedge from standard weather data.     

Effect of thermal treatment on the quality of cloudy apple juice

Apple juice from eight different varieties of apples was heated at high-temperature (60-90 degrees C) and short-time (20-100 s) (HTST) combinations. To determine the effect of heating conditions on enzymatic browning and cloud stability in apple juices, the activity of polyphenol oxidase and pectinesterase was analyzed and correlated with the thermal treatment conditions and the quality of the juice. Additional investigations included the measurement of pH value, soluble solid content, titratable acidity, color, and turbidity after 3 and 6 months. The results showed that HTST treatment at 80 degrees C already inactivated polyphenol oxidase, whereas pectinesterase activity was reduced to half and could even at 90 degrees C not be inactivated completely. In fact, highest residual pectinesterase activity was found at 60 degrees C. Heating at 70 degrees C caused stable pectinesterase activity and even a slight increase for 50 and 100 s heating times. Turbidity and lightness increased after HTST treatment. In particular, differences in cloud stability between the varieties were measured. HTST parameters did not correlate with the residual cloud stability after 6 months. The sensory evaluation revealed that only a few combinations were distinguishable. The best stability of cloud and color in relation to heat impact was achieved by HTST treatment between 70 degrees C/100 s and 80 degrees C/20 s.     

Exogenous induction of cerebral beta-amyloidogenesis is governed by agent and host

Protein aggregation is an established pathogenic mechanism in Alzheimer's disease, but little is known about the initiation of this process in vivo. Intracerebral injection of dilute, amyloid-beta (Abeta)-containing brain extracts from humans with Alzheimer's disease or beta-amyloid precursor protein (APP) transgenic mice induced cerebral beta-amyloidosis and associated pathology in APP transgenic mice in a time- and concentration-dependent manner. The seeding activity of brain extracts was reduced or abolished by Abeta immunodepletion, protein denaturation, or by Abeta immunization of the host. The phenotype of the exogenously induced amyloidosis depended on both the host and the source of the agent, suggesting the existence of polymorphic Abeta strains with varying biological activities reminiscent of prion strains.