Pub Date : 1999-01-01DOI: 10.4314/JASSA.V5I1.16908
F. Mhlanga, S. Makuza, V. Rusika
As evidence has shown that dairy cattle from more variable herds may be over-evaluated, the effect of heterogeneous variances across herd production levels on genetic evaluation was investigated using lactation milk production records of Zimbabwean Holstein cows. A total of 12420 first lactation milk production records of Zimbabwean Holstein cows were split into three groups (Low, Medium, High) according to herd production level. Preliminary analysis to determine the fixed effects of herd average group, herd, class of cow, year of calving, month of calving and age at calving on milk yield was done. An animal model containing additive genetic effects pertaining to cows, dams and sires was implemented in AI-REML package to estimate additive genetic, residual and phenotypic variances and heritability estimates. The F-max test was used to test for homogeneity of variances. All fixed effects significantly affected milk yield (P Journal of Applied Science in Southern Africa Vol.5, No.1 pp. 55-62
{"title":"Intra-herd production level variances for milk yield of Zimbabwean Holstein cows","authors":"F. Mhlanga, S. Makuza, V. Rusika","doi":"10.4314/JASSA.V5I1.16908","DOIUrl":"https://doi.org/10.4314/JASSA.V5I1.16908","url":null,"abstract":"As evidence has shown that dairy cattle from more variable herds may be over-evaluated, the effect of heterogeneous variances across herd production levels on genetic evaluation was investigated using lactation milk production records of Zimbabwean Holstein cows. A total of 12420 first lactation milk production records of Zimbabwean Holstein cows were split into three groups (Low, Medium, High) according to herd production level. Preliminary analysis to determine the fixed effects of herd average group, herd, class of cow, year of calving, month of calving and age at calving on milk yield was done. An animal model containing additive genetic effects pertaining to cows, dams and sires was implemented in AI-REML package to estimate additive genetic, residual and phenotypic variances and heritability estimates. The F-max test was used to test for homogeneity of variances. All fixed effects significantly affected milk yield (P Journal of Applied Science in Southern Africa Vol.5, No.1 pp. 55-62","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88940107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-01-01DOI: 10.4314/JASSA.V5I1.16904
D. Simbi, O. Chinyamakobvu
A failure investigation of a welded waste heat boiler steel shell that developed transverse cracks was carried out in 1996 to determine the cause of failure as well as propose measures to be adopted to prevent similar failures occurring in the future. The boiler had been in service for several years before two cracks across two traversing circumferential welds were discovered on the underside during routine inspection. Chemical and metallographic analyses indicated that the boiler plate was made from a conventional C-Min steel and that it was certainly suitable for the purpose. The boiler interior showed massive deposition of a calcareous sludge on the walls and tube bundles. This was attributed to an excessive use of sodium orthophosphate to reduce the hardness of the boiler feed water. The high levels of Na+ and PO 43- ions found in both the sludge and boiler feed water analyses were taken as confirmatory evidence. Feed water quality monitored data for the period January 1994 to October 1995 showed pH values that were in excess of 12.4, a figure much higher than the recommended pH range 8 to 11. The high pH is thought to have been responsible for the occurrence of cracking as a result of caustic embrittlement. This point of view is supported by the observation of intergranular separation in the microstructures adjacent to the crack paths. Journal of Applied Science in Southern Africa Vol.5, No.1 pp. 9-24
{"title":"Sludge deposition and caustic embrittlement in the pre-mature failure of a waste heat boiler steel plate","authors":"D. Simbi, O. Chinyamakobvu","doi":"10.4314/JASSA.V5I1.16904","DOIUrl":"https://doi.org/10.4314/JASSA.V5I1.16904","url":null,"abstract":"A failure investigation of a welded waste heat boiler steel shell that developed transverse cracks was carried out in 1996 to determine the cause of failure as well as propose measures to be adopted to prevent similar failures occurring in the future. The boiler had been in service for several years before two cracks across two traversing circumferential welds were discovered on the underside during routine inspection. Chemical and metallographic analyses indicated that the boiler plate was made from a conventional C-Min steel and that it was certainly suitable for the purpose. The boiler interior showed massive deposition of a calcareous sludge on the walls and tube bundles. This was attributed to an excessive use of sodium orthophosphate to reduce the hardness of the boiler feed water. The high levels of Na+ and PO 43- ions found in both the sludge and boiler feed water analyses were taken as confirmatory evidence. Feed water quality monitored data for the period January 1994 to October 1995 showed pH values that were in excess of 12.4, a figure much higher than the recommended pH range 8 to 11. The high pH is thought to have been responsible for the occurrence of cracking as a result of caustic embrittlement. This point of view is supported by the observation of intergranular separation in the microstructures adjacent to the crack paths. Journal of Applied Science in Southern Africa Vol.5, No.1 pp. 9-24","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80415876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-01-01DOI: 10.4314/JASSA.V5I1.16903
M. Zaranyika, C. Mahamadi, A. Mathuthu
The performance of the Chitungwiza, Marondera and Crowborough Sewage treatment plants in Zimbabwe were evaluated by monitoring the levels of suspended solids (SS), dissolved solids (DS), dissolved oxygen (DO), biological oxygen demand (BOD), K+, Na+, CA2+, Mg2+. Cl-, SO 42-,NO3- No1-, and PO 43- Ions in the period May 1994 to September 1995. The performance of the three plants were assessed by comparison to the UK conventional effluent 30:20 standard for SS, BOD, cl-, NO3- and PO 43- irons. All three plants conformed to this standard for nitrate ion, while for Chitungwiza and Marondera plants the levels of BOD, SS, chloride and phosphate ions were in excess of the Standard. In addition the Chitungwiza sewage plant effluent contained very high levels of nitrite ion. Journal of Applied Science in Southern Africa Vol.5, No.1 pp. 1-8
{"title":"A comparative study of the performance of the Chitungwiza Marondera and Crowborough sewage treatment plants in Zimbabwe","authors":"M. Zaranyika, C. Mahamadi, A. Mathuthu","doi":"10.4314/JASSA.V5I1.16903","DOIUrl":"https://doi.org/10.4314/JASSA.V5I1.16903","url":null,"abstract":"The performance of the Chitungwiza, Marondera and Crowborough Sewage treatment plants in Zimbabwe were evaluated by monitoring the levels of suspended solids (SS), dissolved solids (DS), dissolved oxygen (DO), biological oxygen demand (BOD), K+, Na+, CA2+, Mg2+. Cl-, SO 42-,NO3- No1-, and PO 43- Ions in the period May 1994 to September 1995. The performance of the three plants were assessed by comparison to the UK conventional effluent 30:20 standard for SS, BOD, cl-, NO3- and PO 43- irons. All three plants conformed to this standard for nitrate ion, while for Chitungwiza and Marondera plants the levels of BOD, SS, chloride and phosphate ions were in excess of the Standard. In addition the Chitungwiza sewage plant effluent contained very high levels of nitrite ion. Journal of Applied Science in Southern Africa Vol.5, No.1 pp. 1-8","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79069304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-01-01DOI: 10.4314/JASSA.V5I2.16916
A. Siwela, N. Nziramasanga
Aflatoxins are highly toxic and carcinogenic chemicals produced by fungi of the Aspergillus family. As the fungi may be found growing on virtually all stored agricultural commodities and foodstuffs, many countries have put in place regulations to control the levels of afJatoxins and other mycotoxins that may be found contaminating foodstuffs and stock feeds. Current regulations and aflatoxin control in Zimbabwe is based on a voluntary code of conduct drawn in 1971 which putthe action limit at between 4f,glkg to 20!.glkg aflatoxin G, (AFG,J or Sf,glkg to 2Sf,glk9 aflatoxin B, (AFB1) for human consumption. Any commodity contaminated by Aflatoxin greater than these limits should be used for stock feed and those below these limits could be used for the export market. The 2Sfl9/kg AFB, action limit has been levi sed to 20f'9/kg by the statutory instrument of 1990 under the Food Standard Act of 1971. This paper reviews work that has been done in the past ten years in the monitoring and control of aflatoxin in foodstuffs and feeds. Aflatoxin levels in foods, stock feeds, urine and human milk from a cross section of the population have shown that the population and livestock are exposed to aflatoxin. Disease outbreaks in livestock have also been linked to aflatoxins and other mycotoxins. It is recommended that aflatoxin monitoring be intensified in support of the Food Standards Act and the voluntary code of conduct be made into a legal instrument to control transmission of aflatoxin in the food chain.
{"title":"Regulatory aspects of aflatoxin control in Zimbabwe: a review","authors":"A. Siwela, N. Nziramasanga","doi":"10.4314/JASSA.V5I2.16916","DOIUrl":"https://doi.org/10.4314/JASSA.V5I2.16916","url":null,"abstract":"Aflatoxins are highly toxic and carcinogenic chemicals produced by fungi of the Aspergillus family. As the fungi may be found growing on virtually all stored agricultural commodities and foodstuffs, many countries have put in place regulations to control the levels of afJatoxins and other mycotoxins that may be found contaminating foodstuffs and stock feeds. Current regulations and aflatoxin control in Zimbabwe is based on a voluntary code of conduct drawn in 1971 which putthe action limit at between 4f,glkg to 20!.glkg aflatoxin G, (AFG,J or Sf,glkg to 2Sf,glk9 aflatoxin B, (AFB1) for human consumption. Any commodity contaminated by Aflatoxin greater than these limits should be used for stock feed and those below these limits could be used for the export market. The 2Sfl9/kg AFB, action limit has been levi sed to 20f'9/kg by the statutory instrument of 1990 under the Food Standard Act of 1971. This paper reviews work that has been done in the past ten years in the monitoring and control of aflatoxin in foodstuffs and feeds. Aflatoxin levels in foods, stock feeds, urine and human milk from a cross section of the population have shown that the population and livestock are exposed to aflatoxin. Disease outbreaks in livestock have also been linked to aflatoxins and other mycotoxins. It is recommended that aflatoxin monitoring be intensified in support of the Food Standards Act and the voluntary code of conduct be made into a legal instrument to control transmission of aflatoxin in the food chain.","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90186879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.4314/JASSA.V4I2.16901
W. Chivasa, D. Harris, C. Chiduza, P. Nyamudeza, A. Mashingaidze
A journal article on Zimbabwe farmers’ perceptions of the importance of good stand establishment.
一篇关于津巴布韦农民对良好立足点重要性的看法的期刊文章。
{"title":"Agronomic practices, major crops and farmers perceptions of the importance of good stand establishment in Musikavanhu Communal Area, Zimbabwe","authors":"W. Chivasa, D. Harris, C. Chiduza, P. Nyamudeza, A. Mashingaidze","doi":"10.4314/JASSA.V4I2.16901","DOIUrl":"https://doi.org/10.4314/JASSA.V4I2.16901","url":null,"abstract":"A journal article on Zimbabwe farmers’ perceptions of the importance of good stand establishment.","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87061517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.4314/jassa.v4i2.16900
T. Mushipe, C. Chiduza, B. Maasdorp
A research paper on the manipulation of irrigation in order to achieve higher sugar-cane yields in Zimbabwe.
一篇关于在津巴布韦操纵灌溉以实现更高甘蔗产量的研究论文。
{"title":"The manipulation of irrigation and drying-off schedules of sugar cane to increase sucrose yields","authors":"T. Mushipe, C. Chiduza, B. Maasdorp","doi":"10.4314/jassa.v4i2.16900","DOIUrl":"https://doi.org/10.4314/jassa.v4i2.16900","url":null,"abstract":"A research paper on the manipulation of irrigation in order to achieve higher sugar-cane yields in Zimbabwe.","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84596936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.4314/JASSA.V4I2.16899
P. K. Jain, L. K. Sharma
{"title":"The physics of blackbody radiation: A review","authors":"P. K. Jain, L. K. Sharma","doi":"10.4314/JASSA.V4I2.16899","DOIUrl":"https://doi.org/10.4314/JASSA.V4I2.16899","url":null,"abstract":"","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90968854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.4314/JASSA.V3I1.16896
L. Sibanda, L. Ndlovu, M. Bryant
{"title":"Reproductive performance of Matebele goats in a semi-arid environment under smallholder management","authors":"L. Sibanda, L. Ndlovu, M. Bryant","doi":"10.4314/JASSA.V3I1.16896","DOIUrl":"https://doi.org/10.4314/JASSA.V3I1.16896","url":null,"abstract":"","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81531403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.4314/JASSA.V3I1.16889
A. Masuka, C. Namichila
A JASSA study on tobacco plant infection in Zimbabwe from samples observed between 1985-1996.
1985-1996年在津巴布韦观察到的烟草植物侵染的JASSA研究。
{"title":"Characterisation of Phytophthora nicotianae isolates causing root and stem rot of tobacco","authors":"A. Masuka, C. Namichila","doi":"10.4314/JASSA.V3I1.16889","DOIUrl":"https://doi.org/10.4314/JASSA.V3I1.16889","url":null,"abstract":"A JASSA study on tobacco plant infection in Zimbabwe from samples observed between 1985-1996.","PeriodicalId":43299,"journal":{"name":"JASSA-The Finsia Journal of Applied Finance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79817640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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