Spatial modeling of wind speed around windbreaks

This paper presents a model to integrate windbreak shelter effects into a Geographic Information System (GIS). The GIS procedure incorporates the 1999 version windbreak sub-model of the Wind Erosion Prediction System (WEPS). Windbreak shelter is modeled in terms of friction velocity reduction, which is a function of wind speed and direction, distance from the barrier, windbreak height, porosity, width, and orientation. A first application of the model was conducted at a study area with an extensive windbreak network in England (Thetford, East Anglia). Windbreak characteristics (windbreak type, height, width, porosity, and location) were recorded. Porosity was estimated from digitized B/W silhouettes. To evaluate the network effectiveness, a windbreak network shelter index (SI) was proposed in terms of average reduction of friction velocity over the area due to network shelter. The network was found to give good protection, but the windbreak distribution was not optimal in relation to the wind vector distribution.     

The importance of non‐penetrated papillae formation in the resistance response of triticale to powdery mildew (Blumeria graminis)

Triticale is the intergeneric hybrid between wheat and rye. With the expansion of the triticale growing area, powdery mildew has emerged and become a significant disease on this new host. Recent research demonstrated that this ‘new’ powdery mildew on triticale has emerged through a host range expansion of powdery mildew of wheat. Moreover, isolates sampled from triticale still infect their previous host, wheat, but isolates sampled from wheat hardly infect triticale. Race‐specific and adult‐plant resistance have been identified in triticale cultivars. The main objective of this study was to characterize the cellular basis of powdery mildew resistance in triticale. Commonalities with resistance responses in other cereals such as wheat, barley and oat are discussed. A detailed comparative histological study of various resistance responses during cross‐inoculation of either virulent or avirulent wheat and triticale isolates on both hosts was carried out. The present data provide evidence that for incompatible interactions, the formation of non‐penetrated papillae is the predominant resistance response, while the hypersensitive response (HR) acts as a second line of defence, to cut the fungus off from nutrients, if penetration resistance fails. It is not clear yet what causes the slower growth and reduced colony size of triticale isolates when inoculated on wheat. Possibly, post‐penetration resistance mechanisms, other than HR, are switched on during these (semi‐) compatible interactions. Molecular studies on gene expression and gene function of defence‐related genes might reveal further insights into the genetic basis of these resistance responses.     

Chromosome segregation errors as a cause of DNA damage and structural chromosome aberrations

Various types of chromosomal aberrations, including numerical (aneuploidy) and structural (e.g., translocations, deletions), are commonly found in human tumors and are linked to tumorigenesis. Aneuploidy is a direct consequence of chromosome segregation errors in mitosis, whereas structural aberrations are caused by improperly repaired DNA breaks. Here, we demonstrate that chromosome segregation errors can also result in structural chromosome aberrations. Chromosomes that missegregate are frequently damaged during cytokinesis, triggering a DNA double-strand break response in the respective daughter cells involving ATM, Chk2, and p53. We show that these double-strand breaks can lead to unbalanced translocations in the daughter cells. Our data show that segregation errors can cause translocations and provide insights into the role of whole-chromosome instability in tumorigenesis.     

Electrical stunning followed by decapitation or chilling of African catfish (Clarias gariepinus): assessment of behavioural and neural parameters and product quality

The objective of this study was to assess neural and behavioural responses in farmed African catfish (Clarias gariepinus) upon electrical stunning in combination with decapitation or chilling. To assess the possibility of scaling up one or both experimental methods, two trials were performed in an experimental setting. The product quality of the collected samples was compared with the currently applied industrial method: live chilling. After electrical stunning in combination with decapitation, the fish showed spikes alternated with theta and delta waves on the EEG, followed by minimal brain activity after 20±10 s. The same traces on the EEGs were observed after electrical stunning in combination with chilling. Here, minimal brain activity occurred after 22±11 s. Within a confidence level of 95%, the percentage of African catfish that was effectively stunned after administration of an electrical current of 1.5 A dm⁻², 300 V (50 Hz a.c.), followed by decapitation or chilling was above 91%. The analysis yield and evolution of liquid loss showed significant (P<0.05) differences among the batches, which could be explained by the stunning method used. The course values of the pH in the different batches were significantly (P<0.05) dependent on the stunning method, sex and location (visceral or skin side). It is concluded that African catfish can be stunned effectively using electrical stunning in a water tank, followed by decapitation or chilling in ice. Dutch commercial processors prefer to combine electrical stunning with chilling in flake ice in a rotating tumbler, as the outer slime layer is then removed, which facilitates further processing.     

Adaptive conjoint analysis to determine perceived risk factors of farmers, veterinarians and AI technicians for introduction of BHV1 to dairy farms

A study was carried out to determine the possibility of a more-closed farming system for (Dutch) dairy farms. The objective of the study was to provide effective and economically profitable management advice for improving the animal-health status of farms. Management measures will only be successfully applied if supported by farmers and their advisors (such as veterinarians). Therefore, the perception of farmers and advisors of the importance of various risk factors for the introduction of diseases to a farm was determined by using bovine herpes virus type 1 (BHV1) as an example.

As part of the study, an evening-long workshop was organized and run thrice. In total, 49 farmers, veterinarians and AI technicians participated in these workshops. The computerized questionnaire technique was based on adaptive conjoint analysis (ACA). ACA has the advantage that participants can work with a large number of risk factors in a relatively short period of time. Another advantage of ACA (compared with standard questionnaires) is that the answers from each participant can be checked with regard to consistency with respect to the importance assigned to them. Data from participants with inconsistent responses can be excluded from further analyses. The results of the ACA interview were compared with the risk factors reported in the literature as being associated with BHV1 status (e.g. purchase of cattle, participation in cattle shows) and with farmers' actual management to prevent the introduction of diseases.

The workshop participants were all operating in the dairy sector and they seemed well aware of the risk of direct animal contacts for the introduction of BHV1. Farmers thought visitors to be more risky than did AI technicians and (especially) veterinarians. Farmers who purchased cattle or participated in cattle shows were of the opinion that the risks of direct animal contacts were more important than did farmers who were not involved in those practices. Farmers whose farms were BHV1-positive (and participated in cattle shows more often) thought the risk of participation smaller than did farmers with BHV1-negative farms.     

三丁酸甘油酯能促进仔猪健康的肠道,使仔猪快乐

丁酸已被证明对动物肠道健康有益,能够提高仔猪的消化率。由于该化合物有恶臭味,因此已采用不少措施来克服这一问题,如包被技术。那么,以三丁酸甘油酯形式使用又会呈现出什么情况呢?     

竹叶叶绿素荧光季节变化的模型设计

在寻找可再生能源和生物基材料方面,竹子已经被作为一种高产的生物质产品,可以用来作为土壤污染的修复性植物。由于这个原因,一个产量指示的增长模型需要一个健康的指标参数来检测植物的性能。因此,本研究对位于爱尔兰都伯林的Ballyboughalo公司的毛竹蒿草(Phyllostachys humilis)叶子的叶绿素荧光进行了测量。本研究测量结果涵盖了这种竹类每个节点的叶子,并且建立在了随季节性变化的基础上。最常使用的叶绿素荧光参数是Fv/Fm值,又称TRO/ABS (即被困的光子与吸收的光子数之比)。随季节的推移以及这个参数较大的变化,本研究将春天与一年中其它的季节进行对比观察测量。在过去的一年,这种植物的上部叶片比下部叶片表现更好。本研究的发现被整合在一个数学模型中,其目的是为预测和解释在其它立地条件下的植物的性能。     

Avian H5N1 influenza in cats

During the 2003 to 2004 outbreak of avian influenza A (H5N1) virus in Asia, there were anecdotal reports of fatal infection in domestic cats, although this species is considered resistant to influenza. We experimentally inoculated cats with H5N1 virus intratracheally and by feeding them virus-infected chickens. The cats excreted virus, developed severe diffuse alveolar damage, and transmitted virus to sentinel cats. These results show that domestic cats are at risk of disease or death from H5N1 virus, can be infected by horizontal transmission, and may play a role in the epidemiology of this virus.