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21.
Richard Idro Godfrey Otieno Steven White Anderson Kahindi Greg Fegan Bernhards Ogutu Sadik Mithwani Kathryn Maitland Brian GR Neville Charles RJC Newton 《Malaria journal》2005,4(1):1-10
Background
Intermittent preventive treatment of malaria during pregnancy (IPTp) is a key intervention in the national strategy for malaria control in Tanzania. SP, the current drug of choice, is recommended to be administered in the second and third trimesters of pregnancy during antenatal care (ANC) visits. To allow for a proper design of planned scaling up of IPT services in Tanzania it is useful to understand the IPTp strategy's acceptability to health managers, ANC service providers and pregnant women. This study assesses the knowledge, attitudes and practices of these groups in relation to malaria control with emphasis on IPTp services.Methods
The study was conducted in February 2004, in Korogwe District, Tanzania. It involved in-depth interviews with the district medical officer (DMO), district hospital medical officer in charge and relevant health service staff at two peripheral dispensaries, and separate focus group discussions (FGDs) with district Council Health Management Team members at district level and pregnant women at dispensary and community levels.Results
Knowledge of malaria risks during pregnancy was high among pregnant women although some women did not associate coma and convulsions with malaria. Contacting traditional healers and self-medication with local herbs for malaria management was reported to be common. Pregnant women and ANC staff were generally aware of SP as the drug recommended for IPTp, albeit some nurses and the majority of pregnant women expressed concern about the use of SP during pregnancy. Some pregnant women testified that sometimes ANC staff allow the women to swallow SP tablets at home which gives a room for some women to throw away SP tablets after leaving the clinic. The DMO was sceptical about health workers' compliance with the direct observed therapy in administering SP for IPTp due to a shortage of clean water and cups at ANC clinics. Intensified sensitization of pregnant women about the benefits of IPTp was suggested by the study participants as an important approach for improving IPTp compliance.Conclusion
The successful implementation of the IPTp strategy in Tanzania depends on the proper planning of, and support to, the training of health staff and sustained sensitization of pregnant women at health facility and community levels about the benefits of IPTp for the women and their unborn babies. 相似文献22.
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24.
Impact of rainfall manipulations and biotic controls on soil respiration in Mediterranean and desert ecosystems along an aridity gradient 总被引:1,自引:0,他引:1
Spatially heterogeneous ecosystems form a majority of land types in the vast drylands of the globe. To evaluate climate‐change effects on CO2 fluxes in such ecosystems, it is critical to understand the relative responses of each ecosystem component (microsite). We investigated soil respiration (Rs) at four sites along an aridity gradient (90–780 mm mean annual precipitation, MAP) during almost 2 years. In addition, Rs was measured in rainfall manipulations plots at the two central sites where ~30% droughting and ~30% water supplementation treatments were used over 5 years. Annual Rs was higher by 23% under shrub canopies compared with herbaceous gaps between shrubs, but Rs at both microsites responded similarly to rainfall reduction. Decreasing precipitation and soil water content along the aridity gradient and across rainfall manipulations resulted in a progressive decline in Rs at both microsites, i.e. the drier the conditions, the larger was the effect of reduction in water availability on Rs. Annual Rs on the ecosystem scale decreased at a slope of 256/MAP g C m?2 yr?1 mm?1 (r2=0.97). The reduction in Rs amounted to 77% along the aridity gradient and to 16% across rainfall manipulations. Soil organic carbon (SOC) decreased with declining precipitation, and variation in SOC stocks explained 77% of the variation in annual Rs across sites, rainfall manipulations and microsites. This study shows that rainfall manipulations over several years are a useful tool for experimentally predicting climate‐change effects on CO2 fluxes for time scales (such as approximated by aridity gradients) that are beyond common research periods. Rainfall reduction decreases rates of Rs not only by lowering biological activity, but also by drastically reducing shrub cover. We postulate that future climate change in heterogeneous ecosystems, such as Mediterranean and deserts shrublands will have a major impact on Rs by feedbacks through changes in vegetation structure. 相似文献
25.
Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance 总被引:4,自引:0,他引:4
REIMO KINDLER KLAUS KAISER DAVID C. WALMSLEY CHRISTIAN BERNHOFER NINA BUCHMANN PIERRE CELLIER WERNER EUGSTER GERD GLEIXNER THOMAS GRŨNWALD ALEXANDER HEIM ANDREAS IBROM STEPHANIE K. JONES MIKE JONES KATJA KLUMPP WERNER KUTSCH KLAUS STEENBERG LARSEN SIMON LEHUGER BENJAMIN LOUBET REBECCA MCKENZIE EDDY MOORS BRUCE OSBORNE KIM PILEGAARD CORINNA REBMANN MATTHEW SAUNDERS MICHAEL W. I. SCHMIDT MARION SCHRUMPF JANINE SEYFFERTH UTE SKIBA JEAN‐FRANCOIS SOUSSANA MARK A. SUTTON CINDY TEFS BERNHARD VOWINCKEL MATTHIAS J. ZEEMAN MARTIN KAUPENJOHANN 《Global Change Biology》2011,17(2):1167-1185
Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands, and croplands across Europe. Biogenic contributions to DIC were estimated by means of its δ13C signature. Leaching of biogenic DIC was 8.3±4.9 g m?2 yr?1 for forests, 24.1±7.2 g m?2 yr?1 for grasslands, and 14.6±4.8 g m?2 yr?1 for croplands. DOC leaching equalled 3.5±1.3 g m?2 yr?1 for forests, 5.3±2.0 g m?2 yr?1 for grasslands, and 4.1±1.3 g m?2 yr?1 for croplands. The average flux of total biogenic carbon across land use systems was 19.4±4.0 g C m?2 yr?1. Production of DOC in topsoils was positively related to their C/N ratio and DOC retention in subsoils was inversely related to the ratio of organic carbon to iron plus aluminium (hydr)oxides. Partial pressures of CO2 in soil air and soil pH determined DIC concentrations and fluxes, but soil solutions were often supersaturated with DIC relative to soil air CO2. Leaching losses of biogenic carbon (DOC plus biogenic DIC) from grasslands equalled 5–98% (median: 22%) of net ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small solubility of CO2 in acidic forest soil solutions and large NEE. Leaching of CH4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems. 相似文献
26.
Allelic frequency and genotypes of prion protein at codon 136 and 171 in Iranian Ghezel sheep breeds
Siamak Salami Reza Ashrafi Zadeh Mir Davood Omrani Fatemeh Ramezani Amir Amniattalab 《朊病毒》2011,5(3):228-231
PrP genotypes at codons 136 and 171 in 120 Iranian Ghezel sheep breeds were studied using allele-specific PCR amplification and compared with the well-known sheep breeds in North America, the United States and Europe. The frequency of V allele and VV genotype at codon 136 of Ghezel sheep breed was significantly lower than AA and AV. At codon 171, the frequency of allele H was significantly lower than Q and R. Despite the similarities of PrP genotypes at codons 136 and 171 between Iranian Ghezel sheep breeds and some of the studied breeds, significant differences were found with others. Planning of effective breeding control and successful eradication of susceptible genotypes in Iranian Ghezel sheep breeds will not be possible unless the susceptibility of various genotypes in Ghezel sheep breeds to natural or experimental scrapie has been elucidated.Key words: scrapie, Ghezel sheep breed, PrP genotyping, allele specific amplification, codon 136, codon 171Scrapie was first described in England in 1732,1 and it is an infectious neurodegenerative fatal disease of sheep and goats belonging to the group of transmissible subacute spongiform encephalopathies (TSEs), along with bovine spongiform encephalopathy (BSE), chronic wasting disease and Creutzfeldt-Jakob disease.2,3 The term prion, proteinaceous infectious particles, coined by Stanley B. Prusiner, was introduced, and he presents the idea that the causal agent is a protein.4 Prion proteins are discovered in two forms, the wild-type form (PrPc) and the mutant form (PrPSc).5 Although scrapie is an infectious disease, the susceptibility of sheep is influenced by genotypes of the prion protein (PrP) gene.2,6 Researchers have found that the PrP allelic variant alanine/arginine/arginine (ARR) at codons 136, 154 and 171 is associated with resistance to scrapie in several breeds.7–14 Most of the sheep populations in the Near East and North African Region (84% of the total population of 255 million) are raised in Iran, Turkey, Pakistan, Sudan, Algeria, Morocco, Afghanistan, Syria and Somalia.15 In 2003, the Iranian sheep population was estimated at 54,000,000 head. The Ghezel sheep breed, which also is known as Kizil-Karaman, Mor-Karaman, Dugli, Erzurum, Chacra, Chagra, Chakra, Gesel, Gezel, Kazil, Khezel, Khizel, Kizil, Qezel, Qizil and Turkish Brown, originated in northwestern Iran and northeastern Turkey. By considering sheep breeds as one of the main sources of meat, dairy products and related products, a global screening attempt is started in different areas. In compliance with European Union Decision 2003/100/EC, each member state has introduced a breeding program to select for resistance to TSEs in sheep populations to increase the frequency of the ARR allele. A similar breeding program is established in United States and Canada. The Near East and North African Region still needs additional programs to help the global plan of eradication of scrapie-susceptible genotypes. The current study was the first to assess the geographical and molecular variation of codons 136 and 171 polymorphism between Iranian Ghezel sheep breed and well-known sheep breeds.Polymorphism at codon 136 is associated with susceptibility to scrapie in both experimental and natural models.10,11,13,16 17 and Austrian Carynthian sheep.18 Swiss White Alpine showed higher frequency of allele V at position 136 than Swiss Oxford Down, Swiss Black-Brown Mountain and Valais Blacknose.19 Comparison of polymorphism at codon 136 in the current study with some of other breeds (20 some flock of Hampshire sheep21 with current study, but the frequency of it is higher than that of some other breeds.
Open in a separate windowIt has been found that a polymorphism at codon 171 also is associated with susceptibility to experimental scrapie in Cheviot sheep16 and natural scrapie in Suffolk sheep.22 As shown in 23 They also found that different breeds show different predominant genotypes in ewes and rams.23 Different PrP genotypes were found at codon 171 in Austrian sheep breeds, but QQ has higher frequency than others.18 In some kinds of Swiss breeds, allelic frequencies of allele Q was higher than R.19 Distribution of prion protein codon 171 genotypes in Hampshire sheep revealed that different flocks shows different patterns.21 The frequency of PrP genotypes at codon 171 in Iranian Ghezel breeds was similar to some sheep breeds, like the Suffolk breed of Oklahoma sheep, but it was completely different from others (PrP genotypes at codon 172 Breed Allelic frequency Genotypes Reference Q R H RR QR QQ QH RH HH Iranian Iranian Ghezel breeds (n = 120) 55.00 43.33 1.67 23.33 36.67 36.67 0.00 3.33 0.00 Current study Oklahoma sheep (n = 334) De Silva, et al.20 Suffolk 40.95 59.05 0.00 37.07 43.97 18.97 0.00 0.00 0.00 Hampshire 51.89 48.11 0.00 21.70 52.83 25.47 0.00 0.00 0.00 Dorset 67.75 31.25 0.00 7.95 46.59 45.45 0.00 0.00 0.00 Montadale 62.96 37.04 0.00 14.81 44.44 40.74 0.00 0.00 0.00 Hampshire (n = 201) 72.14 26.60 1.26 5.00 42.00 50.00 2.00 1.00 0.00 Youngs, et al.21 German Sheep Breeds (n = 660) Kutzer, et al.28 Bleu du Maine 37.8 62.2 0.00 46.96 30.44 22.6 0.00 0.00 0.00 Friesian Milk S. 90.45 8.9 0.65 1.27 15.3 82.8 0.00 0.00 0.64 Nolana 42.3 57.8 0.00 36.62 42.26 21.13 0.00 0.00 0.00 Suffolk 68.4 27.6 4.0 16.1 21.84 55.17 4.6 1.15 1.15 Texel 55.35 29.7 14.9 12.56 26.83 36.36 11.25 7.36 5.63 Swiss Sheep (n = 200) Gmur, et al.19 Swiss Oxford Down 32.00 68.00 - - - - - - - Swiss Black-Brown M. 70.00 30.00 - - - - - - - Valais Blacknose 85.00 15.00 - - - - - - - Swiss White Alpine 27.00 73.00 - - - - - - - Austrian Sheep (n = 112) Sipos, et al.18 Tyrolean mountain sheep 74.30 25.80 0.00 2.90 45.70 51.40 0.00 0.00 0.00 Forest sheep 77.00 19.20 3.80 11.50 15.40 69.20 0.00 0.00 3.80 Tyrolean stone sheep 81.50 14.80 3.70 0.00 29.60 62.90 7.40 0.00 0.00 Carynthian sheep 72.80 23.00 4.20 4.20 41.70 13.00 8.40 0.00 0.00
Table 1
Comparison of PrP allelic and genotype frequencies at codon 136 in different breedsBreed | A (%) | V (%) | AA (%) | AV (%) | VV (%) | Reference |
Iranian Ghezel breeds (n = 120) | 77.50 | 22.5 | 65.00 | 25.00 | 10.00 | Current study |
Oklahoma sheep (n = 334) | De Silva, et al.27 | |||||
Suffolk | 99.24 | 0.76 | 98.48 | 1.52 | 0.00 | |
Hampshire | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Dorset | 92.6 | 7.94 | 87.30 | 9.52 | 3.17 | |
Montadale | 77.66 | 22.34 | 59.57 | 36.17 | 4.26 | |
Hampshire (n = 48) | 93.75 | 6.25 | 88.00 | 12.00 | 0.00 | Youngs, et al.21 |
German Sheep Breeds (n = 660) | 92.89 | 7.11 | 87.80 | 10.47 | 1.73 | Kutzer, et al.28 |
Bleu du Maine | 83.47 | 16.53 | 69.56 | 27.83 | 2.61 | |
Friesian Milk S. | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Nolana | 90.13 | 9.87 | 85.90 | 8.46 | 5.64 | |
Suffolk | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Texel | 90.87 | 9.13 | 82.16 | 17.41 | 0.43 | |
Swiss Sheep (n = 200) | 92.5 | 7.5 | Gmur, et al.19 | |||
Swiss Oxford Down | 93.00 | 7.00 | - | - | - | |
Swiss Black-Brown M. | 99.00 | 1.00 | - | - | - | |
Valais Blacknose | 100 | 0.00 | - | - | - | |
Swiss White Alpine | 88.00 | 22.00 | - | - | - | |
Austrian Sheep (n = 112) | 98.95 | 1.05 | 98.95 | 0.00 | 1.05 | Sipos, et al.18 |
Tyrolean mountain sheep | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Forest sheep | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Tyrolean stone sheep | 100 | 0.00 | 100 | 0.00 | 0.00 | |
Carynthian sheep | 95.80 | 4.20 | 95.80 | 0.00 | 4.20 |