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Impact of enclosure management on soil properties and microbial biomass in a restored semi-arid rangeland, Kenya

Journal of Arid Land 2014年第5期6卷 561-570页

作者： Stephen M MUREITHI Ann VERDOODT charles kk gachene Jesse T NJOKA Vivian O WASONGA Stefaan De NEVE Elizabeth MEYERHOFF Eric Van RANST Laboratory of Soil Science Department of Geology and Soil Science Ghent University Department of Land Resources Management and Agricultural Technology University of Nairobi Research Unit of Soil Degradation and Conservation Department of Soil Management Ghent University Rehabilitation of Arid Environments Trust

Rangeland degradation is a serious problem throughout sub-Saharan Africa and its restoration is a challenge for the management of arid and semi-arid areas. In Lake Baringo Basin of Kenya, communities and individual farmers are restoring indigenous vegetation inside enclosures in an effort to combat severe land degradation and address their livelihood problems. This study evaluated the impact of enclosure management on soil properties and microbial biomass, being key indicators of soil ecosystem health. Six reseeded communal enclosures using soil embankments as water-harvesting structures and strictly regulated access were selected, varying in age from 13 to 23 years. In six private enclosures, ranging from 3 to 17 years in age, individual farmers emulated the communal enclosure strategy and restored areas for their exclusive use. Significant decreases in bulk density, and increases in the soil organic carbon, total nitrogen and microbial biomass contents and stocks were found in the enclosures as compared with the degraded open rangeland. In the private enclosures, the impact of rehabilitation on the soil quality was variable, and soil quality was in general lower than that obtained under communal management. The significant increase of absolute stocks of carbon, nitrogen and microbial biomass compared to the degraded open rangeland indicates the potential for the restoration of soil quality through range rehabilitation. Over-sowing with indigenous legume fodder species could improve total nitrogen content in the soil and nutritional value of the pastures as well.

关键词： rangeland degradation enclosures microbial biomass rehabilitation reseeding soil quality Kenya

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SUSTAINABLE DEVELOPMENT OF CROP-LIVESTOCK FARMS IN AFRICA

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Frontiers of Agricultural Science and Engineering 2021年第1期8卷 175-181页

作者： Mariana C.RUFINO charles K.K.gachene Rodrigue V.C.DIOGO James HAWKINS Alice A.ONYANGO Ousmane M.SANOGO Ibrahim WANYAMA Gabriel YESUF David E.PELSTER Lancaster Environment Centre Lancaster UniversityLancasterLA14YQUK Department of Land Resource Management and Agricultural Technology University of NairobiNairobiP.O.Box 29053-00625Kenya Faculty of Agricultural Sciences University of ParakouParakouP.O.Box 123Benin International Livestock Research Institute(ILRI) NairobiP.O.Box 30709-00100Kenya Institut d'Economie Rurale SikassoBP 16Mali Agriculture and Agri-Food Canada 2560 Blvd HochelagaQuebec CityG1V 2J3Canada

Crop-livestock farms across Africa are highly variable due to in agroecological and socioeconomic factors,the latter shaping the demand and supply of livestock ***-livestock farms in Africa in the 20-first century are very different from most mixed farms elsewhere in the *** crop-livestock farms are smaller in size,have fewer livestock,lower productivity and less dependency on imported feed than farms in most countries of Europe,the Americas and the intensive agricultural systems of *** paper discusses the role African crop-livestock farms have in the broader socio-agricultural economy,and how these are likely to change adapting to pressures brought on by the intensification of food *** intensification implies increasing land productivity(more food per hectare),often leading to more livestock heads per farm,producing fertilized feeds in croplands and importing feed supplements from the *** discussion includes(1)the links between crop yields,soil fertility and crop-livestock integration,(2)the increasing demand for livestock products and the land resources required to meet to this demand,and(3)the opportunities to integrate broader societal goals into the development of crop-livestock *** is ample room for development of crop-livestock farms in Africa,and keeping integration as part of the development will help prevent many of the mistakes and environmental problems related to the intensification of livestock production observed elsewhere in the *** development can integrate biodiversity,climate change adaptation and mitigation to the current goals of increasing productivity and food *** inclusion of broader goals could help farmers access the level of finance required to implement changes.

关键词： finance integrate goals

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Prostate cancer detection upon transrectal ultrasound-guided biopsy in relation to digital rectal examination and prostate-specific antigen level： what to expect in the Chinese population？

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Asian Journal of Andrology 2015年第5期17卷 821-825,I0010页

作者： Jeremy YC Teoh Steffi kk Yuen James HL Tsu charles KW Wong Brian SH Ho Ada TL Ng Wai-Kit Ma Kwan-Lun Ho Ming-Kwong Yiu Department of Surgery Division of Urology Queen Mary Hospital University of Hong Kong Hong Kong China

We investigated the prostate cancer detection rates upon transrectal ultrasound （TRUS）-guided biopsy in relation to digital rectal examination （DRE） and prostate-specific antigen （PSA）, and risk factors of prostate cancer detection in the Chinese population. Data from all consecutive Chinese men who underwent first TRUS-guided prostate biopsy from year 2000 to 2013 was retrieved from our database. The prostate cancer detection rates with reference to DRE finding and PSA level of 〈 4, 4-10, 10.1-20, 20.1-50 and 〉 50 ng ml^-1 were investigated. Multivariate logistic regression analyses were performed to investigate for potential risk factors of prostate cancer detection. A total of 2606 Chinese men were included. In patients with normal DRE, the cancer detection rates were 8.6%, 13.4%, 21.8%, 41.7% and 85.2% in patients with PSA 〈 4, 4-10, 10.1-20, 20.1-50 and 〉 50 ng ml^-1 respectively. In patients with abnormal DRE, the cancer detection rates were 12.4%, 30.2%, 52.7%, 80.6% and 96.4% in patients with PSA 〈 4, 4-10, 10.1-20, 20.1-50 and 〉 50 ng m1-1 respectively. Older age, smaller prostate volume, larger number of biopsy cores, presence of abnormal DRE finding and higher PSA level were associated with increased risk of prostate cancer detection upon multivariate logistic regression analyses （P 〈 0.001）. Chinese men appeared to have lower prostate cancer detection rates when compared to the Western population. Taking the different risk factors into account, an individualized approach to the decision of TRUS-guided biopsy can be adopted.

关键词： Chinese digital rectal examination prostate biopsy prostate cancer prostate-specific antigen

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The performance characteristics of prostate-specific antigen and prostate-specific antigen density in Chinese men

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Asian Journal of Andrology 2017年第1期19卷 113-116页

作者： Jeremv YC Teoh Steffi kk Yuen James HL Tsu charles KW Wong Brian SH Ho Ada TL Ng Wai-Kit Ma Kwan-Lun Ho Ming-Kwong Yiu Division of Urology Department of Surgery Queen Mary Hospital University of Hong Kong Hong Kong China

We investigated the performance characteristics of prostate-specific antigen （PSA） and PSA density （PSAD） in Chinese men. All Chinese men who underwent transrectal ultrasound-guided prostate biopsy （TRUS-PB） from year 2000 to 2013 were included. The receiver operating characteristic （ROC） curves for both PSA and PSAD were analyzed. The sensitivity, specificity, positive predictive value （PPV） and negative predictive value （NPV） at different cut-off levels were calculated. A total of 2606 Chinese men were included. For the ROC, the area under curve was 0.770 for PSA （P〈 0.001） and 0.823 for PSAD （P〈 0.001）. PSA of 4.5 ng ml^-1 had sensitivity of 94.4%, specificity of 14.1%, PPV of 29.5%, and NPV of 86.9%; PSAD of 0.12 ng ml^-1cc^-1 had sensitivity of 94.5%, specificity of 26.6%, PPV of 32.8%, and NPV of 92.7%. On multivariate logistic regression analyses, PSA cut-off at 4.5 ng ml^-1 （OR 1.61, 95% CI 1.05-2.45, P = 0.029） and PSAD cut-off at 0.12 ng ml^-1 cc^-1 （OR 6.22, 95% CI 4.20-9.22, P 〈 0.001） were significant predictors for prostate cancer detection on TRUS-PB. In conclusion, the performances of PSA and PSAD at different cut-off levels in Chinese men were very different from those in Caucasians. PSA of 4.5 ng ml^-1 and PSAD of O. 12 ng ml^-1 cc^-1 had near 95% sensitivity and were significant predictors of prostate cancer detection in Chinese men.

关键词： Chinese prostate cancer transrectal ultrasound-guided prostate biopsy prostate-specific antigen prostate-specific antigen density

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