Epidemiology of Campylobacter jejuni in raccoons (Procyon lotor) on swine farms and in conservation areas in southern Ontario     

Nadine A. Vogt  David L. Pearl  Eduardo N. Taboada  Steven K. Mutschall  Kristin J. Bondo  Claire M. Jardine 《Zoonoses and public health》2021,68(1):19-28

Campylobacter is a leading cause of foodborne illness in humans worldwide. Sources of infection are often difficult to identify, and are, generally, poorly understood. Recent work suggests that wildlife may represent a source of Campylobacter for human infections. Using a repeated cross‐sectional study design, raccoons were trapped on five swine farms and five conservation areas in southern Ontario from 2011 to 2013. Our objectives were to: (a) assess the impact of seasonal, climatic, location, annual and raccoon demographic factors on the occurrence of Campylobacter jejuni in these animals; and (b) identify clusters of C. jejuni in space, time and space‐time using spatial scan statistics. Multi‐level multivariable logistic regression was used to examine the odds of isolating C. jejuni, with site and animal modelled as random intercepts. The following independent variables were examined: raccoon age and sex, year, location type, season, temperature and rainfall. A total of 1,096 samples were obtained from 627 raccoons; 46.3% were positive for C. jejuni. The following interactions and their main effects were significant (p < .05) and retained in the final model: season × temperature, year × rainfall, year × temperature. Based on the results from our multivariable model and spatial scan statistics, climatic variables (i.e. rainfall, temperature and season) were associated with the carriage of C. jejuni by raccoons, but the effects were not consistent, and varied by location and year. Although raccoons may pose a zoonotic risk due to their carriage of Campylobacter, further work is required to characterize the transmission and movement of this microorganism within the ecosystem.  相似文献   

Response of <Emphasis Type="Italic">Theobroma cacao</Emphasis> and <Emphasis Type="Italic">Inga edulis</Emphasis> seedlings to cross-inoculated populations of arbuscular mycorrhizal fungi   总被引：1，自引：0，他引：1  

Luis Iglesias  Eduardo Salas  Humberto A. Leblanc  Pekka Nygren 《Agroforestry Systems》2011,83(1):63-73

Response of Theobroma cacao L. (cacao) and the shade tree Inga edulis Mart. (inga) seedlings from an organically-grown cacao plantation to inoculation with native arbuscular mycorrhizae forming fungi (AMF) was studied in a cross-inoculation assay under greenhouse conditions. Seedlings of inga and cacao were grown in pots filled with heat-treated soil from the plantation. Control was heat-treated soil without inoculum and roots of cacao and inga from the plantation were applied as AMF inocula. Undisturbed soil blocks were used as a “positive control” of the inoculation potential of untreated soil and roots combined. No AMF structures were observed in the roots of either species in the heat-treated control. All inocula were infective in both hosts and the differences in the total AMF colonization percentage between the hosts were not significant but inga had significantly higher colonization by hyphal coils and arbuscules. Cacao roots but neither inga roots nor soil block inocula stimulated cacao growth. All inocula significantly increased growth of inga, which had higher relative mycorrhizal responsiveness than cacao. Thus, in spite of the strong infectivity of the inocula in both hosts, cacao and inga responded differently to the same AMF populations. The strong conspecific preference of cacao suggests that attention must be paid to the AMF inoculum used for this species. However, the strong response of inga to cacao root inoculum indicates that the two species may share same AMF symbionts, thus enabling positive interactions between them, including formation of common mycelial networks.  相似文献   

Phenotypic plasticity of stem water potential correlates with crop load in horticultural trees     

Sadras VO  Trentacoste ER 《Tree physiology》2011,31(5):494-499

Conceptual models accounting for the influence of source:sink ratio on water relations of trees are theoretically relevant from a physiological perspective and practically important for irrigation scheduling. Midday stem water potential of horticultural trees often declines with increasing crop load but the actual response depends on environmental, management and plant factors. Here we advance a quantitative synthesis of the response of stem water potential to crop load from the perspective of phenotypic plasticity, defined as 'the amount by which the expression of individual characteristics of a genotype are changed by different environments'. Data sets of stem water potential for contrasting crop loads were compiled for apple (Malus domestica L. Borkh.), olive (Olea europea L.), peach (Prunus persica L.), pear (Pyrus communis L.) and plum (Prunus domestica L.). Phenotypic plasticity of stem water potential was calculated as the slope of the linear regression between stem water potential for each crop load and the environmental mean of stem water potential across crop loads. Regression lines for trees with different crop load diverged with decreasing environmental mean stem water potential. For the pooled data, plasticity of stem water potential was a linear function of relative crop load. This represents a significant shift in perspective: the effect of crop load on the trait per se (stem water potential) is environmentally contingent, but the effect of crop load on the plasticity of the trait is not. We conclude that research on the effects of crop load on tree water relations would return more robust results if plant traits are considered from the dual perspective of the trait per se and its plasticity.  相似文献   

Compiling Market and Other Financial Data on Smallholder Forestry in Leyte, the Philippines   总被引：1，自引：1，他引：0  

Edwin Cedamon  Steve Harrison  John Herbohn  Eduardo Mangaoang 《Small-Scale Forestry》2011,10(2):149-162

Data collection and maintenance of databases concerning smallholder forestry presents special problems in developing countries. This paper examines forestry data collection experiences in a series of research projects in Leyte, Philippines, supported by the Australian Centre for International Agricultural Research, and the prospects for developing forestry accounting networks. A variety of financial data have been collected in relation to seedling production, plantation performance and timber marketing. Seedling production cost and revenue data have been obtained through snapshot surveys conducted in 2002 and 2008, and repeated attempts have been made to estimate financial returns from growing the most popular tree species. Diverse sources have been identified for timber market information. On the supply side, these include government records of registered plantations, obtaining inventory data from barangay (community) leaders, and reporting information about timber available for harvest on community notice boards. On the demand side, official records of registered timber merchants have been accessed, a detailed survey of timber processors has been conducted, and estimates are being made of apparent per capita timber consumption by district. Experiences in the Philippines reinforce that the potential for forestry accounting networks is limited by the resource-constrained situations of developing countries, placing greater reliance on one-off surveys. Use of pre-existing local networks and institutional structures offers potential for routine collection of forestry data, such as through barangay (village) leaders in the Philippines.  相似文献   

Promising agroforestry systems in Venezuela     

Eduardo E. Escalante 《Agroforestry Systems》1985,3(2):209-221

The main agroforestry systems in Venezuela are the multispecies plant associations in integrated coffee production system and the silvopastoral system. This paper describes the functional and structural aspects of these systems. The multilayered coffee production systems are practised mainly in the premontane moist forest of the Andes region, but are also found in other areas of the country. Various tree species are used for shade and as fence in big coffee plantations, whereas in small units with traditional production pattern, coffee is planted along with many other species, often constituting a 3–4 layer canopy. Available data are presented on the production as well as some socioeconomic aspects.The silvopastoral systems are found in the tropical dry forest (savannas) and in the very dry tropical forest of the semiarid zones of the country. A large number of trees and shrubs are found in these pastoral areas where they play both productive (fodder and feed) and service (shelter) roles.Although both these systems are practised over large areas of the country, practically no research has been done to improve them. In order to strengthen national capability to undertake such research, international support of cash and as well as technical advice is needed.

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Resumen Los principales sistemas agroforestales en Venezuela son el Sistema integrado de producción de café y el sistema silvopastoril. En el presente trabajo se describen aspectos funcionales y estructurales de esos sistemas. El sistema de producción multi-estratificado de café es practicado principalmente en el bosque húmedo premontano de la región andina, per también es frecuentemente observado en áreas del país. Diferentes especies de árboles son utilizados como sombra y como cercos vivos en las grandes plantaciones de café, mientras que en las pequenas unidades con un patrón de producción tradicional, el café es plantado junto con una gran diversidad de especies constituyendo un dosel vegetativo de 3–4 estratos.Información disponible sobre producción y algunos aspectos socio-económicos es presentada en el trabajo.Los sistemas silvopastoriles son encontrados en el bosque seco tropical (sabanas o llanos) y en el bosque muy seco tropical de las zonas semiaridas del país. Un gran número de árboles y arbustos se encuentran en esas áreas de pastoreo donde juegan un doble rol, producción (forraje ya alimento) y servicio (refugio y abrigo).Aunque ambos sistemas son practicados en grandes áreas del país, practicamente ninguna investigación se ha llevado a cabo para mejoralos. Con el objeto de fortalecer la capacidad en el país de llevar a cabo tal tipo de investigación, se hace necessario recursos economicós y asesaría técnica por parte de organizaciones internacionales.

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Asymmetry in the structure of the ABC transporter-binding protein complex BtuCD-BtuF     

Hvorup RN  Goetz BA  Niederer M  Hollenstein K  Perozo E  Locher KP 《Science (New York, N.Y.)》2007,317(5843):1387-1390

BtuCD is an adenosine triphosphate-binding cassette (ABC) transporter that translocates vitamin B12 from the periplasmic binding protein BtuF into the cytoplasm of Escherichia coli. The 2.6 angstrom crystal structure of a complex BtuCD-F reveals substantial conformational changes as compared with the previously reported structures of BtuCD and BtuF. The lobes of BtuF are spread apart, and B12 is displaced from the binding pocket. The transmembrane BtuC subunits reveal two distinct conformations, and the translocation pathway is closed to both sides of the membrane. Electron paramagnetic resonance spectra of spin-labeled cysteine mutants reconstituted in proteoliposomes are consistent with the conformation of BtuCD-F that was observed in the crystal structure. A comparison with BtuCD and the homologous HI1470/71 protein suggests that the structure of BtuCD-F may reflect a posttranslocation intermediate.  相似文献   

Effect of a bacterial inoculum and additive on dry matter in situ degradability of sugarcane silage     

José A Reyes-Gutiérrez  Oziel D Montaez-Valdez  Ramón Rodríguez-Macias  Mario Ruíz-López  Eduardo Salcedo-Pérez  Cándido E Guerra-Medina 《中国农业科学(英文版)》2015,(3):497-502

The objective of this study was to evaluate the effect of adding a bacterial inoculum and a handmade additive to sugarcane silage(SCS) on the in situ digestibility of dry matter(DM). The treatments were: T1) sugarcane silage(SCS) and T2) sugarcane silage with 1% inoculum and 1% additive(SCS+). The bacterial inoculum consisted of 10.0% molasses, 1.0% yogurt, 5.0% chicken manure, 0.5% urea, and 83.0% water, and the additive was formulated with 1.0% urea, 0.1% ammonium sulfate, and 0.25% phosphorus. In situ dry matter digestibility(DMD) was determined using the nylon bag technique with four cows equipped with ruminal fistulas. Cows were fed with ensiled sugarcane supplemented with 1 kg of commercial concentrate. 5 g of ground sample for each sugarcane treatment were weighted in nylon bags and incubated for 4, 8, 12, 24, 48, and 72 h in a completely randomized design with six replicates. The DMD(%) was higher(P<0.05) for SCS+ for all incubation times when compared with SCS. There were no differences in ruminal p H between the treatments for all the incubation times. The data suggested that the sugarcane silage with bacterial inoculum and additive could be an alternative for providing forage for ruminants during the season of low growth and quality grass.  相似文献   

Ultrahigh strength in nanocrystalline materials under shock loading     

Bringa EM  Caro A  Wang Y  Victoria M  McNaney JM  Remington BA  Smith RF  Torralva BR  Van Swygenhoven H 《Science (New York, N.Y.)》2005,309(5742):1838-1841

Molecular dynamics simulations of nanocrystalline copper under shock loading show an unexpected ultrahigh strength behind the shock front, with values up to twice those at low pressure. Partial and perfect dislocations, twinning, and debris from dislocation interactions are found behind the shock front. Results are interpreted in terms of the pressure dependence of both deformation mechanisms active at these grain sizes, namely dislocation-based plasticity and grain boundary sliding. These simulations, together with new shock experiments on nanocrystalline nickel, raise the possibility of achieving ultrahard materials during and after shock loading.  相似文献   

Incorporation of Buriti Endocarp Flour in Gluten-free Whole Cookies as Potential Source of Dietary Fiber     

Fernanda?Salamoni?BeckerEmail author  Clarissa?Damiani  Adriane?Alexandre?Machado?de?Melo  Paulo?Rogério?Siriano?Borges  Eduardo?Valério?de Barros?Vilas Boas 《Plant foods for human nutrition (Dordrecht, Netherlands)》2014,69(4):344-350

Cookies were prepared by replacing a mixture of brown rice flour (70 %) and corn starch (30 %) (BRFCS) by buriti endocarp flour (BEF) (0, 5, 10, 15 or 20 %). BEF figured as a potential source of dietary fiber (70.53 g 100 g^?1), especially of insoluble fiber (67.50 g 100 g^?1), and gluten-free whole cookies showed increased dietary fiber content by adding 5, 10, 15 and 20 % BEF (8.58 to 20.02 g 100 g^?1) when compared to control cookie (6.91 g 100 g^?1). The addition of BEF affected diameter, spread ratio, color and texture of cookies. All cookies added with BEF were darker, harder and presented smaller diameter and smaller spread ratio than the control cookie. These difference increased proportionally to level of substitution of BRFSC by BEF. Gluten-free whole cookies with up to 15 % BEF were well accepted by consumers. Therefore, the use of BEF in cookies may increase the availability of functional ingredients source of dietary fiber for celiac consumers, add economic value to buriti processing by-products and decrease environmental impacts due to the high amounts of waste generated by buriti processing industries.  相似文献   

Assessing the use of erosion modeling to support payment for environmental services programs   总被引：1，自引：0，他引：1  

Jorge Enoch Furquim Werneck Lima  Walszon Terllizzie Araújo Lopes  Fabiana de Gois Aquino  Eduardo Cyrino Oliveira-Filho  Edson Eyji Sano  Felippe Damião Mello di Silva 《Journal of Soils and Sediments》2014,14(7):1258-1265

Purpose

Payment for environmental services (PES) has assumed increasing importance in discussions about sustainable development strategies. Many of the PES programs are based on water erosion control and the corresponding environmental and economic benefits generated in the basins where they are implemented. The main objective of this study was to show how erosion susceptibility models can support PES programs.

Materials and methods

The application of the Universal Soil Loss Equation (USLE) in the Sarandi Experimental River Basin (32.7 km²), located in the Federal District, Brazil, was used as a study case. Then a scheme for organizing knowledge about ecosystem services related to erosion control and water resources was performed. Considering the generated scheme, the USLE results, the land use map, and the water use in the region, we evaluated how erosion modeling could support PES programs.

Results and discussion

The results show that a large part of the study basin (90%) presents “low” susceptibility to erosion, which is significant in terms of the use and conservation of ecosystem services, as well as being a limitation regarding the need for the implantation of PES programs for erosion control. Incentives for maintaining the natural vegetation in areas with higher erosion susceptibility have the greatest potential to justify PES programs in the study basin, and the sanitation company is the potential payer for erosion control in the Sarandi River Basin.

Conclusions

The application of the USLE in a spatially distributed form proved to be an important support tool for land management and the implementation of PES policies.  相似文献