Surface heating in metals irradiated by fast I.R. laser pulses

For this laser output to be optimized to the requirements of the workpiece the behaviour of the irradiated material must be known with reasonable accuracy. This requires modelling of the interaction processes for the materials concerned. The validity of the Fourier conduction theory within the context of high powered laser irradiation has been raised by several workers who have proved it to be invalid both in terms of its resolution of sharp energy gradients and inability to cope with non-equilibrium energy transport between electrons and lattice phonons. An alternative theory of energy transport based on the Electron Kinetic theory is therefore presented and the results compared with those obtained using the Fourier conduction theory. It is found that the results obtained using the Electron theory are in better agreement with available experimental results. The new model is then extended to include evaporation effects. Previous computer simulation of high mean power, high pulse repetition frequency (p.r.f.) lasers have predicted the characteristics of the first output pulse only. This pulse, however, is not representative of the subsequent pulses as the simulation is initiated using conditions based on thermodynamic equilibrium. Using a modified kinetic model which incorporates plasma temperature variation, optical cavity characteristics and transverse gas flow, the simulation was extended to include the second output power pulse. A substantial difference was found between the first and second pulse profiles. This extended model is essential as it identifies further the control variables which can be used to optimize beam characteristics for material processing applications. It also gives closer agreement with experimental measurements made under continuously running conditions

Canopy management, leaf fall and litter quality of dominant tree species in the banana agroforestry system in Uganda

Small-scale farmers in the banana-coffee agro-zone of Central Uganda plant andmaintain trees to provide a range of benefits. However, the impact of trees on soil fertility and crop yields is small. On many farms, trees exist in infinite numbers, compositions, with no proper spacing, sequencing and canopy management  recommendations. The objectives of this study were to: quantify and compare leaf fall and leaf litter biomass for the dominant tree species subjected to different pruning regimes and during different seasons and determine the nutrient  concentrations in leaf litter materials in order to assess their potential to improve soil fertility. A survey was conducted on 30 randomly selected farms to examine and  document the tree species. Four tree species were dominant; Ficus natalensis (15.3%), Albizia coriaria (10.2%), Artocarpus  heterophyllus (10.0%) and Mangifera indica (9.2%). Experiments such as canopy pruning, collecting leaf fall and weights of pruned leaf biomass were established for the four dominant trees on five randomly selected farms. A total of 120 trees were subjected to three pruning regimes (0%, 25% and 50%). Litter traps (1 m × 1 m) were placed 2 m from the tree trunk to collect falling leaves. Leaf biomass was collected from pruned branches and eighed. Leaf samples were collected from pruned leaves and a composite sample analysed for carbon and nutrient concentrations. Results showed that 40 tree and shrub species belonging to 21 families existed on farms. Leaf fall was highest in the dry season and A. Heterophyllus registered the highest amount. Leaf biomass from pruned trees was heaviest for M. indica (42.4 ±3 kg) in the wet season and at the 50% pruning regime (45.7± 2.1kg). Total  nutrient concentrations were in the order A. coriaria>F. natalensis>A.heterophyllus>M.indica. We concluded that F. natalensis and A. Coriaria should be integrated more into the agroforestry system to improve soil fertility. A.heterophyllus and M.indica should be planted on farm boundaries. The 50% pruning regime was the best and should be carried out during the wet season.Key words: Tree species, canopy management, leaf fall, nutrient concentrations, soil fertilit

Farmers’ knowledge of the banana (Musa Sp.) agroforestry systems in Kiboga District, Central Uganda

Banana is a major food and cash crop in Uganda, particularly in the central and southwestern regions. However, production is still below attainable yields and at the same time declining due to a number of reasons, with low soil fertility being paramount. Few farmers use inorganic fertilizers, with majority of them relying mainly on organic supplements including integration of trees/shrubs. However, trees and shrubs exist on banana farms in undefined numbers and composition, with no spacing and canopy management recommendations. Also, there is limited information on farmers’ knowledge on these systems. A survey was, therefore, conducted on 70 randomly selected farms in Kiboga district, central Uganda to assess farmers’ knowledge of, as well as identify trees and shrubs species and banana cultivars in their agro-ecologies. A total of 1,558 trees and shrubs belonging to 40 species and 21 families were recorded in the study area (52 trees/shrubs per banana plantation). These were dominated by Jackfruit, Artocarpus heterophyllus (15%), Natal fig, Ficus natalensis (10%), Albizia, Albizia coriaria (10%) and mango, Mangifera indica (9%). Further, 1,779 banana mats belonging to nine (9) cultivars and three (3) genome groups were observed growing underneath these four commonest tree species (2.6 banana mats per tree). The highest number of banana mats was observed growing underneath F. natalensis (54%) and A. coriaria (42%). Most (87%) observed banana cultivars belonged to the cooking East African Highland Banana (Musa AAA-EAHB) and dominated by Ndibwabalangira (21%). Farmers reported 25 benefits they derive from banana-trees/shrubs integration; with shade and firewood (38%), as well as income and timber (35%) being the main benefits reported. They also reported that the highest percentage of benefits was derived from F. natalensis (44%) and A. coriaria (32%). Of the four (4) most prevalent tree species, A. coriaria (100%) and F. natalensis (96%) were reported as good companion plant to bananas, whereas, A. heterophyllus (99%) and M. indica (97%) were regarded as bad companion plants. Farmers preferred a tree that allows light penetration (96%), is compatible with bananas and other crops (87%) and has easily decomposable leaves (83%). Therefore, F. natalensis and A. coriaria should be integrated in banana agrosystems for soil fertility improvement whereas; A. heterophyllus and M. indica be planted on farm boundaries. However, the best-bet spacing and pruning regimes for these trees should be determined to minimize the negative attributes as much as possible.Keywords: Albizia coriaria, Artocarpus heterophyllus, banana cultivars, benefits, companions, Ficus natalensis, Mangifera indica, tree-specie

Canopy management, leaf fall and litter quality of dominant tree species in the banana agroforestry system in Uganda

Small-scale farmers in the banana-coffee agro-zone of Central Uganda plant andmaintain trees to provide a range of benefits. However, the impact of trees on soil fertility and crop yields is small. On many farms, trees exist in infinite numbers, compositions, with no proper spacing, sequencing and canopy management  recommendations. The objectives of this study were to: quantify and compare leaf fall and leaf litter biomass for the dominant tree species subjected to different pruning regimes and during different seasons and determine the nutrient  concentrations in leaf litter materials in order to assess their potential to improve soil fertility. A survey was conducted on 30 randomly selected farms to examine and  document the tree species. Four tree species were dominant; Ficus natalensis (15.3%), Albizia coriaria (10.2%), Artocarpus  heterophyllus (10.0%) and Mangifera indica (9.2%). Experiments such as canopy pruning, collecting leaf fall and weights of pruned leaf biomass were established for the four dominant trees on five randomly selected farms. A total of 120 trees were subjected to three pruning regimes (0%, 25% and 50%). Litter traps (1 m × 1 m) were placed 2 m from the tree trunk to collect falling leaves. Leaf biomass was collected from pruned branches and eighed. Leaf samples were collected from pruned leaves and a composite sample analysed for carbon and nutrient concentrations. Results showed that 40 tree and shrub species belonging to 21 families existed on farms. Leaf fall was highest in the dry season and A. Heterophyllus registered the highest amount. Leaf biomass from pruned trees was heaviest for M. indica (42.4 ±3 kg) in the wet season and at the 50% pruning regime (45.7± 2.1kg). Total  nutrient concentrations were in the order A. coriaria>F. natalensis>A.heterophyllus>M.indica. We concluded that F. natalensis and A. Coriaria should be integrated more into the agroforestry system to improve soil fertility. A.heterophyllus and M.indica should be planted on farm boundaries. The 50% pruning regime was the best and should be carried out during the wet season.Key words: Tree species, canopy management, leaf fall, nutrient concentrations, soil fertilit

The use of common bean (Phaseolus vulgaris ) traditional varieties and their mixtures with commercial varieties to manage bean fly (Ophiomyia spp .) infestations in Uganda

The bean fly (Ophiomyia spp.) is considered the most economically damaging field insect pest of common beans in Uganda. Despite the use of existing pest management approaches, reported damage has remained high. Forty-eight traditional and improved common bean varieties currently grown in farmers’ fields were evaluated for resistance against bean fly. Data on bean fly incidence, severity and root damage from bean stem maggot were collected. Generalized linear mixed model (GLMM) revealed significant resistance to bean fly in the Ugandan traditional varieties. A popular resistant traditional variety and a popular susceptible commercial variety were selected from the 48 varieties and evaluated in pure and mixed stands. The incidence of bean fly infestation on both varieties in mixtures with different arrangements (systematic random versus rows), and different proportions within each of the two arrangements, was measured and analysed using GLMMs. The proportion of resistant varieties in a mixture and the arrangement type significantly decreased bean fly damage compared to pure stands, with the highest decrease in damage registered in the systematic random mixture with at least 50 % of resistant variety. The highest reduction in root damage, obvious 21 days after planting, was found in systematic random mixtures with at least 50 % of the resistant variety. Small holder farmers in East Africa and elsewhere in the world have local preferences for growing bean varieties in genetic mixtures. These mixtures can be enhanced by the use of resistant varieties in the mixtures to reduce bean fly damage on susceptible popular varieties

Effect of Fertiliser and Mulching on Bean Infestation and Damage by Bean Fly

The damage caused by the bean fly (Ophiomyia sp.), which is the major insect pest of beans in Uganda, is more serious in poor soils and under drought conditions. There is, however, limited information on cause and effect. This study investigated the relationship between fertiliser and the influence of moisture conservation through mulching on bean fly infestation. Fertiliser application significantly increased bean fly oviposition per leaf, number of pupae per plant and plant mortality. Mulching also significantly reduced bean fly pupae density and bean plant mortality. Mulching increased soil moisture content and there was a significant negative relationship between soil moisture content and bean fly pupae density. The influence of fertiliser and mulching on bean fly damage is discussed based on nitrogen and water relationships in plant growth.Les d\ue9g\ue2ts caus\ue9s par la mouche du haricot (Ophiomyia sp.), l\u2019insect-peste majeur du haricot en Uganda, sont plus graves dans les conditions de sols pauvres et de s\ue8cheresse. Les informations sur la cause et effet sont cependant limit\ue9es. Cette \ue9tude a examin\ue9 la relation entre l\u2019engrais et l\u2019influence de la conservation de l\u2019hum\ueedit\ue9 par paillage sur l\u2019infestation de la mouche du haricot. L\u2019application du a augment\ue9 significativement l\u2019oviposition de la mouche du haricot par feuille et le nombre de pupes par plante. Le paillage a r\ue9duit significativement la mouche du haricot, la densit\ue9 des pupes et la mortalit\ue9 de plantes du haricot. Le paillage a augment\ue9 la teneur en hum\ueedit\ue9 du sol et une relation n\ue9gative a \ue9t\ue9 \ue9tablie entre la teneur en hum\ueedit\ue9 du sol et la densit\ue9 en pupes de la mouche du haricot. L\u2019influence de l\u2019engrais et du paillage sur les d\ue9g\ue2ts de la mouche du haricot est discut\ue9e en se basant sur la relation de l\u2019azote et de l\u2019eau dans la croissance de la plante

Willingness to pay (WTP) for HIV and AIDS services in Africa:a descriptive thematic systematic review

Background The African continent has the highest burden of HIV and AIDS, with its response to HIV and AIDS largely donor supported. However, in the face of declining donor support, alternative ways to sustainably support HIV and AIDS responses in Africa are paramount. This systematic review explores the willingness to pay (WTP) for HIV services in Africa as a potentially more sustainable HIV and AIDS service cost recovery approach. Methods A comprehensive systematic search for literature was conducted in PubMed, EMBASE, Web of Science, and CINAHL and websites of HIV and AIDS organisations for studies published until 30 June 2023. Studies were included if they were about WTP, HIV and AIDS services, were conducted in Africa and were published in English. Studies were excluded if they used methods other than WTP and were not about an HIV service. JBI critical appraisal tools were used to assess for quality and risk of bias. Information on the HIV service, the study methods, and factors influencing WTP were extracted. A descriptive thematic analysis was undertaken to synthesise evidence. The findings are summarised in tables and graphs. Results 5,141 records were identified and screened for eligibility from the initial search. After title and abstract screening and removing duplicates, twenty-three articles from 10 countries with 20,780 study participants were included in the final review. There is an uneven distribution of WTP studies across different types of HIV services and across countries. There is evidence of a willingness to pay for HIV services, with the proportion of people reported in individual studies that are willing to pay ranging from 34.3% to 97.1%. However, in most studies (77.3%, 17/22), the amount people are willing to pay cannot cover the full-service cost in an open market. Factors associated with WTP include socio-economic status, beliefs, and knowledge about HIV services. Conclusions This systematic review presents evidence of cost recovery from HIV programs. The main finding is that other resources, beyond out-of-pocket payments, are needed to meet the total cost of any service. This has implications for providing (non-donor-funded) services on a sustainable level in the long term. In interpreting the findings of this study, limitations such as excluding papers not published in English need to be considered. Registration: PROSPERO, CRD42021275215

Willingness to pay (WTP) for HIV and AIDS services in Africa: a descriptive thematic systematic review

# Background The African continent has the highest burden of HIV and AIDS, with its response to HIV and AIDS largely donor supported. However, in the face of declining donor support, alternative ways to sustainably support HIV and AIDS responses in Africa are paramount. This systematic review explores the willingness to pay (WTP) for HIV services in Africa as a potentially more sustainable HIV and AIDS service cost recovery approach. # Methods A comprehensive systematic search for literature was conducted in PubMed, EMBASE, Web of Science, and CINAHL and websites of HIV and AIDS organisations for studies published until 30 June 2023. Studies were included if they were about WTP, HIV and AIDS services, were conducted in Africa and were published in English. Studies were excluded if they used methods other than WTP and were not about an HIV service. JBI critical appraisal tools were used to assess for quality and risk of bias. Information on the HIV service, the study methods, and factors influencing WTP were extracted. A descriptive thematic analysis was undertaken to synthesise evidence. The findings are summarised in tables and graphs. # Results 5,141 records were identified and screened for eligibility from the initial search. After title and abstract screening and removing duplicates, twenty-three articles from 10 countries with 20,780 study participants were included in the final review. There is an uneven distribution of WTP studies across different types of HIV services and across countries. There is evidence of a willingness to pay for HIV services, with the proportion of people reported in individual studies that are willing to pay ranging from 34.3% to 97.1%. However, in most studies (77.3%, 17/22), the amount people are willing to pay cannot cover the full-service cost in an open market. Factors associated with WTP include socio-economic status, beliefs, and knowledge about HIV services. # Conclusions This systematic review presents evidence of cost recovery from HIV programs. The main finding is that other resources, beyond out-of-pocket payments, are needed to meet the total cost of any service. This has implications for providing (non-donor-funded) services on a sustainable level in the long term. In interpreting the findings of this study, limitations such as excluding papers not published in English need to be considered. **Registration**: PROSPERO, CRD42021275215

Effect of fertiliser and mulching on bean infestation and damage by bean fly

(African Crop Science Journal 1999 7(4): 599-604