The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rig...The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rigor in the management of these forests, which can result in the loss of species of high conservation value. The study was carried out in communal forests in the south-east zone of Cameroon. Its aim was to carry out a floristic inventory and then compare the list of species with the IUCN catalog. Twenty-four plots, each with a surface area of 0.2 ha, were set up in the Gari-Gombo communal forest. All timbers with a DBH ≥ 5 cm were systematically counted. A total of 176 species, belonging to 144 genera and 45 families, were surveyed. Fabaceae (42.08%), Malvaceae (39%), Euphorbiaceae (24.64%), Moraceae (20.92%), Apocynaceae (18.64%), Cecropiaceae (16.60%), Ulmaceae (14.76%), Meliaceae (14.61%), Violaceae (14.08%), Combretaceae (12.67%), Theobroma cacao (21.17%), Baphia leptobotrys (18.06%), Rinorea sp. (14.09%), Musanga cecropioides (12.18%), Terminalia superba (10.32%), Neosloetiopsis kamerunensis (10.14%), Celtis zenkeri (8.29%) and Alstonia boonei (7.77%) were the most important taxa. Nearly 90% of the species in this forest are Guinean species, with a dominance of Guinean-Congolese species (66%). Fourteen (14) threatened species have been identified in the FCGG. This study, which highlights the rich biodiversity of communal forests, is important for guiding biodiversity conservation policies in ecosystems used for production.展开更多
Wastewater treatment is a problem with much acuity in the city of Maradi in general, and particularly in the Communal District I of Maradi. It is for this reason that the present study was conducted which deals with w...Wastewater treatment is a problem with much acuity in the city of Maradi in general, and particularly in the Communal District I of Maradi. It is for this reason that the present study was conducted which deals with wastewater sanitation. The main objective of this study conducted through a survey is to investigate in the domestic wastewater sanitation in the Communal District I of Maradi city. Specifically, the study aims to estimate the amount of wastewater produced by households and to analyze the sanitation system at household and at district levels. The wastewater management practices in this district were assessed through a descriptive cross sectional study in which a total of 129 households were selected by sample distribution technique in the district neighborhoods and studied using interviewer and administered questionnaires at communal and household levels. The results of the study showed that the amount of domestic wastewater generated is quite large, about 32.27 m3 per person per day, and this comes from several sources including showers, laundry, dishwashing and income generating activities. The results also revealed that the unhealthy state of the Communal District I of Maradi is related to the absence of a wastewater treatment system, the methods and practices used in its management, and the population is also largely responsible for this unhealthy state and not willing to participate to a sanitation project.展开更多
Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional st...Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional study carried out between July 1<sup>st</sup> 2015 and June 30 2016, i.e. a duration of one year. Results: A total of 551 patients received advice on various contraceptive methods. Most of this advice was given in the post-partum period (40.2%) and during antenatal care (39.1%). Of the patients advised, 87 (15.8%) used the intrauterine device. The majority of users (93%) were married and uneducated (63.2%), and 39.1% were poor. The majority (56.3%) of intra-uterine devices were inserted in the immediate post-partum period. The majority of women had no adverse events either during the first six weeks (n = 57;65.5%) or at 3<sup>rd</sup> months (n = 75;86.2%) or 6<sup>th</sup> months (n = 76;87.4%) after IUD insertion. Most users remained complication-free throughout the follow-up period (n = 76;87.4% at 6<sup>th</sup> weeks and 3<sup>rd</sup> months, and n = 77;88.5% at 6<sup>th</sup> months). The continuation rate was 89.7% at 6 weeks and 3<sup>rd</sup> months, and 87.4% at 6<sup>th</sup> months after insertion. The majority of users (87.0%) were satisfied with the care they received. Conclusion: This study showed very few complications among intrauterine device users, and high continuation and satisfaction rates. The intrauterine device is a long-acting, effective, reversible and safe contraceptive that can be used by most women for birth spacing in Guinea, where women do not regularly visit health facilities.展开更多
Impacts of grid architectures on temporal diffusion of PV-based communal grids (community owned minigrids or microgrids) in a rural developing community are modelled and simulated using MATLAB/Simulink and a survey-in...Impacts of grid architectures on temporal diffusion of PV-based communal grids (community owned minigrids or microgrids) in a rural developing community are modelled and simulated using MATLAB/Simulink and a survey-informed agent-based model (ABM) developed in NetLogo. Results show that decentralised control architectures stimulate minigrid formations and connections by allowing easy expansions of the minigrids as each decentralised PV system within a minigrid is treated equally and determines its own real and reactive power, eliminating the need for communication links. This also reduces the cost of implementing such a system;fewer connections are realized with centralised controls as such systems require high speed communication links which make them both difficult to expand and expensive to implement. Results also show that multi-master operation modes lead to more communal grid connections compared to single-master operation modes because in the former, all distributed PV systems within a communal grid have the same rank and can act as masters or can be operated as combinations of master generators (VSIs) and PQ inverters, allowing for more design flexibility and easy connections from potential customers.展开更多
The paper presents a cognitive science framework for the analysis of knowledge-based systems,including people, media. simulation and expert systems, resulting in a practical model for the procedures ofknowledge engine...The paper presents a cognitive science framework for the analysis of knowledge-based systems,including people, media. simulation and expert systems, resulting in a practical model for the procedures ofknowledge engineering. Starting with the construct of a social organization model driven by anticipationand thed differentiating this into pesonal scientists with diverse relations to people and their internal andexternal communication, it provides powerful and general model of society. people, and the roles of peoplein society. This model extends naturally ic the role of conventional media in the knowledge processes ofsociety and the new roles of computer-based simulation and expert systems. In particular it provides amodel of knowledge transfer that enables the processes of knowledge engineering to be analyzed andautomated.展开更多
This study aimed at identifying the most preferred water quality tracking system (WQTS) for adoption and the determining factors for the same among the Langata sub County households in Nairobi city, Kenya. Perrenial m...This study aimed at identifying the most preferred water quality tracking system (WQTS) for adoption and the determining factors for the same among the Langata sub County households in Nairobi city, Kenya. Perrenial municipal water shortage in this neighborhood has forced the residents to depend on vended water supplication but whose quality is not possible to verify at the moment. Accordingly, a mobile phone quality tracing application running on blockchain technology platform was developed to fill the gap of provenance tracking. A non-market discrete choice experiments (DCEs) model was deployed in which four-option attribute bundles;with one being the “status quo” choice were presented to each of the 382 randomly sampled respondents from the five wards within the area. Results indicated that Option 2;the communally managed WQTS emerged as the most preferred choice at 53.9%. Secondly, the male factor was identified as the major determinant to this decision. In conclusion, the study proposes for the installation of this new WQTS which will trigger a 12% adjustment of the average household’s monthly water bill. In addition, this paper recommends for a city-wide assessment of residents’ willingness to pay (WTP) for this WQTS, which it deems as an improved response to water shortage problem. Finally, the study contributes to the application of DCEs model in technology adoption literature.展开更多
Collection of Municipal Solid Waste (MSW) is important in every waste management program. Communal container collection systems appear most prevalent in many developing countries. However, this collection system is as...Collection of Municipal Solid Waste (MSW) is important in every waste management program. Communal container collection systems appear most prevalent in many developing countries. However, this collection system is associated with problems such as overflow of waste containers, ground dumping at collection sites, and open/indiscriminate dumping at unauthorized places. The spatial distribution of these activities present potential contamination challenges to water resources. Spatial information on Municipal Solid Waste Collection/Dump Sites (MSWCS) is essential for Municipal Solid Waste Management (MSWM) decision-making, including siting and collection route planning, and dumps cleanup. Integration of Geographic Information Systems (GIS) and Global Positioning Systems (GPS) present a platform to capture, map, and analyze spatial MSWM issues. This study applied GIS and GPS technologies to map MSWCS in Wa town, Ghana. Wa Municipality waste collection system efficiency was analyzed based on spatial availability of communal containers. A GIS model was developed and used to analyze proximity of MSWCS to boreholes drinking water sources. A pollution risk map was also developed to analyze the potential impact of indiscriminate dumps on hand-dug wells and surface water in Wa. The results reveal poor management in a significant number (about 67%) of MSWCS sites. Fifteen percent of mechanized boreholes failed the minimum proximity requirement (≥100 m) of the model. This study findings illustrate that MSWM in developing countries may be improved using GIS and GPS technologies. The approach used for Wa could be replicated in other towns in Ghana and other developing nations with similar MSWM problems to enhance policy and management decision-making.展开更多
West African Dwarf (WAD) goats represent one of the predominant small ruminant breeds raised by resource-limited households in southern Nigeria as well as in the humid west and central Africa. This breed of goats is r...West African Dwarf (WAD) goats represent one of the predominant small ruminant breeds raised by resource-limited households in southern Nigeria as well as in the humid west and central Africa. This breed of goats is renowned for its adaptation to hot and humid environments, high fertility and prolificacy under backyard systems where they are raised almost with zero investment. On account of its contributions to household income and food security in southern Nigeria, there is the need for a detailed phenotypic and genetic characterization as well as the design of breeding strategies for its conservation through sustainable utilization. A critical challenge, however, is that there are no national breeding policies in most of the countries where WAD goats are raised. The objectives of this paper are: to review literature reports on trait-level information and estimates of genetic parameters for some economic characters of WAD goats;and to discuss a communal breeding scheme for its conservation through sustainable utilization. The presentation shows that WAD goats represent a highly diverse population, with particular reference to qualitative and performance-related traits, reflecting the role of traditional institutions in the maintenance of animal diversity in local populations. A genetic improvement programme involving dispersed open nucleus breeding scheme was discussed. The scheme involves backyard WAD goat units in villages as base population and dispersed communally managed schemes that maintain a population of bucks only, as nucleus units. Critical issues such as the definition of breeding goals by farmers, as well as communal project ownership, are emphasized. The ultimate goal of the breeding programme is to create opportunities for community-based management of WAD goat genetic resources for the benefit of backyard goat farmers in the region.展开更多
In this paper power electronics used in PV power generation systems have been reviewed and modelled. PV systems need converters for maximum power point tracking, power conditioning, voltage step-up/down as necessary, ...In this paper power electronics used in PV power generation systems have been reviewed and modelled. PV systems need converters for maximum power point tracking, power conditioning, voltage step-up/down as necessary, and for storage charge-controlling. Inverters are needed for AC loads and for utility grid interfacing. The four basic DC-DC converters commonly used with PV systems have been reviewed and modelled. Different DC-AC inverter types and operational architectures have also been reviewed with the two-stage DC-AC inverter, with the point of common coupling (PCC) at the inverter input, suggested as the most cost-effective and efficient architecture for PV-based communal grids. This is because only one inverter is used for the entire system as opposed to an inverter for every module string, resulting in higher efficiencies, low cost, and low harmonic distortions when compared to systems with PCC at AC terminal. The aim of power conversion/inversion is to extract maximum power possible from the PV system and where necessary, to invert it at close to 100% as possible. Highlight: 1) DC-DC converters are necessary for power conditioning in PV systems;2) DC-AC inverters are necessary for AC loads and for utility grid interfacing;3) DC-AC inverters are also used to control the PV systems when grid connected;4) Best inverter configuration cost-effectively and efficiently allows easy system modifications.展开更多
Vitality is a quality that makes a public space operational and attractive throughout the day in relation to ongoing activities. This parameter can be evaluated through measures such as collective people presence, mix...Vitality is a quality that makes a public space operational and attractive throughout the day in relation to ongoing activities. This parameter can be evaluated through measures such as collective people presence, mixed-use functions, diversity of activities, and other related supportive physical elements. The aim of this research is to evaluate women＇s communal life in terms of vitality measures within public spaces. The commercial setting of Isfahan’s traditional bazaar was selected as the study area. To enhance the credibility of the results, several data collection methods, for example, semi-structured individual interviews （n = 24）, semi-structured focused group interviews （five groups including 28 middle-aged women）, direct observation, snap photography, and unobtrusive behavioral observation of women in communal life within the selected study area, were employed. To analyze the collected data, qualitative content and descriptive analyses were used. Our results indicate that by increasing the vitality of a public space through its related measures, women＇s presence will grow, and through this growth, the quality of their communal life would be enhanced.展开更多
Gas emissions are produced by each economic entity individually—whether they are a large industrial enterprise, a boiler-house or a household (dwelling house). At that, in addition to visible chimneys, there are a lo...Gas emissions are produced by each economic entity individually—whether they are a large industrial enterprise, a boiler-house or a household (dwelling house). At that, in addition to visible chimneys, there are a lot of hidden (unrecorded) sources of emissions in form of ventilation branch pipes. Communal systems for removal and reprocessing of wastes of two types: liquid (municipal sewage lines) and solid (collection and removal of wastes) are operated in populated localities. For the third type of waste—gaseous—a similarly municipal structure does not exist. For the time being there is no possibility for full system control and neutralization of dust and gas wastes because there is no system in the physical form which would enable comprehensive receipt of exit gases from all the city sources for further processing thereof. It is for the first time when a principally new holistic approach to cleaning/treatment of all city dust and gas emissions (wastes) is proposed which consists in creation of a City Communal Aspiration System (Municipal Aspiration System) containing a city communal aspiration network (gas outlets) for receipt/transportation of exhaust (flue) gases and a plant for utilization of such wastes connected to such network. In other words, it is proposed to organize a “City without Chimneys”. The proposed solution permits to remove mass unsystematic and uncontrolled emissions of environmentally harmful gas wastes in cities, reduce climate risks and make the transition to a new level of organization of environmental planning and management and, therefore, eliminates or principally simplifies many ecological difficulties and restrictions in urban planning (inseparably related to ecology) in sanitary rules and standards.展开更多
<span style="font-family:Verdana;">Body weight is a crucial trait that aids farmers in decision-making regarding vaccinations, feeding, marketing and selection during the breeding programs. The study w...<span style="font-family:Verdana;">Body weight is a crucial trait that aids farmers in decision-making regarding vaccinations, feeding, marketing and selection during the breeding programs. The study was conducted to investigate the effect of sex and age on body weight (BW), body condition score (BCS) and some blood biochemical parameters (BBP) and to determine the correlation amongst BW, BCS and BBP of non-descriptive goats at Santombe communal farming system. Blood samples were collected from 33 apparently healthy goats (27 females and 6 males) aged 6 - 8 tooth with a mean BW (32.62 ± 11.39 kg) while BCS (3.17 ± 0.39) was taken by means of palpating the lumbar area, sternum and the ribs. The BCS was rated on a scale of 1 to 5 with 1 being emaciated and 5 being extremely fat. The blood samples were analyzed using Cobas intergra 400 plus </span>che<span style="font-family:Verdana;">mistry analyzer, Roche for biochemical parameters such as total protein (TP), urea, cholesterol (Chol), magnesium (Mg), phosphorous (P) and calcium (Ca) with mean values of 72.79 ± 5.84 mg/l, 2.76 ± 1.16 mmol/l, 2.08 ± 0.40 mmol/l, 1.09 ± 0.09 mmol/l, 2.30 ± 0.49 mmol/l and 2.45 ± 0.12 mmol/l respectively. Sex and age had significant effects on BW, BCS and some biochemical parameters. The BW and BCS for males were significantly higher than for females. Correlation results indicated that BW had a positive relationship with BCS (r = 0.677), TP and BW (r = 0.400), Chol and BCS (r = 0.4025) and Mg and TP (r = -0.075). Age and sex had significant influences on BW, BCS and some blood biochemical parameters. Consideration of the factors can aid in determining the accurate diagnosis of the nutritional status of goats.</span>展开更多
Different droop control methods for PV-based communal grid networks (minigrids and microgrids) with different line resistances (R) and impedances (X) are modelled and simulated in MATLAB to determine the most efficien...Different droop control methods for PV-based communal grid networks (minigrids and microgrids) with different line resistances (R) and impedances (X) are modelled and simulated in MATLAB to determine the most efficient control method for a given network. Results show that active power-frequency (P-f) droop control method is the most efficient for low voltage transmission networks with low X/R ratios while reactive power-voltage (Q-V) droop control method is the most efficient for systems with high X/R ratios. For systems with complex line resistances and impedances, i.e. near unity X/R ratios, P-f or Q-V droop methods cannot individually efficiently regulate line voltage and frequency. For such systems, P-Q-f droop control method, where both active and reactive power could be used to control PCC voltage via shunt-connected inverters, is determined to be the most efficient control method. Results also show that shunt-connection of inverters leads to improved power flow control of interconnected communal grids by allowing feeder voltage regulation, load reactive power support, reactive power management between feeders, and improved overall system performance against dynamic disturbances.展开更多
Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard popu...Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.展开更多
An integral part of risk assessment for natural hazards, communal vulnerability assessment (CVA) is now receiving considerable attention, with the on-going International Decade of Natural Disaster Reduction (IDNDR). T...An integral part of risk assessment for natural hazards, communal vulnerability assessment (CVA) is now receiving considerable attention, with the on-going International Decade of Natural Disaster Reduction (IDNDR). This article expounds the definition of the CVA concept and its implication. In addition, it offers a brief discussion of the reasons why CVA has been neglected and its relationship with socio-economic and physical vulnerability assessment. The article also gives an explorative exposition of the methodology and application of communal vulnerability analysis in risk reduction.展开更多
Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks...Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains-（1） system operation performance; （2） agricultural productivity and economics; （3） financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute （IWMI） and Food and Agriculture Organization （FAO）. Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System （MARI1S）, Lucban, Garab and Divisoria Communal Irrigation Systems （CIS）, respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m3, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.展开更多
文摘The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rigor in the management of these forests, which can result in the loss of species of high conservation value. The study was carried out in communal forests in the south-east zone of Cameroon. Its aim was to carry out a floristic inventory and then compare the list of species with the IUCN catalog. Twenty-four plots, each with a surface area of 0.2 ha, were set up in the Gari-Gombo communal forest. All timbers with a DBH ≥ 5 cm were systematically counted. A total of 176 species, belonging to 144 genera and 45 families, were surveyed. Fabaceae (42.08%), Malvaceae (39%), Euphorbiaceae (24.64%), Moraceae (20.92%), Apocynaceae (18.64%), Cecropiaceae (16.60%), Ulmaceae (14.76%), Meliaceae (14.61%), Violaceae (14.08%), Combretaceae (12.67%), Theobroma cacao (21.17%), Baphia leptobotrys (18.06%), Rinorea sp. (14.09%), Musanga cecropioides (12.18%), Terminalia superba (10.32%), Neosloetiopsis kamerunensis (10.14%), Celtis zenkeri (8.29%) and Alstonia boonei (7.77%) were the most important taxa. Nearly 90% of the species in this forest are Guinean species, with a dominance of Guinean-Congolese species (66%). Fourteen (14) threatened species have been identified in the FCGG. This study, which highlights the rich biodiversity of communal forests, is important for guiding biodiversity conservation policies in ecosystems used for production.
文摘Wastewater treatment is a problem with much acuity in the city of Maradi in general, and particularly in the Communal District I of Maradi. It is for this reason that the present study was conducted which deals with wastewater sanitation. The main objective of this study conducted through a survey is to investigate in the domestic wastewater sanitation in the Communal District I of Maradi city. Specifically, the study aims to estimate the amount of wastewater produced by households and to analyze the sanitation system at household and at district levels. The wastewater management practices in this district were assessed through a descriptive cross sectional study in which a total of 129 households were selected by sample distribution technique in the district neighborhoods and studied using interviewer and administered questionnaires at communal and household levels. The results of the study showed that the amount of domestic wastewater generated is quite large, about 32.27 m3 per person per day, and this comes from several sources including showers, laundry, dishwashing and income generating activities. The results also revealed that the unhealthy state of the Communal District I of Maradi is related to the absence of a wastewater treatment system, the methods and practices used in its management, and the population is also largely responsible for this unhealthy state and not willing to participate to a sanitation project.
文摘Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional study carried out between July 1<sup>st</sup> 2015 and June 30 2016, i.e. a duration of one year. Results: A total of 551 patients received advice on various contraceptive methods. Most of this advice was given in the post-partum period (40.2%) and during antenatal care (39.1%). Of the patients advised, 87 (15.8%) used the intrauterine device. The majority of users (93%) were married and uneducated (63.2%), and 39.1% were poor. The majority (56.3%) of intra-uterine devices were inserted in the immediate post-partum period. The majority of women had no adverse events either during the first six weeks (n = 57;65.5%) or at 3<sup>rd</sup> months (n = 75;86.2%) or 6<sup>th</sup> months (n = 76;87.4%) after IUD insertion. Most users remained complication-free throughout the follow-up period (n = 76;87.4% at 6<sup>th</sup> weeks and 3<sup>rd</sup> months, and n = 77;88.5% at 6<sup>th</sup> months). The continuation rate was 89.7% at 6 weeks and 3<sup>rd</sup> months, and 87.4% at 6<sup>th</sup> months after insertion. The majority of users (87.0%) were satisfied with the care they received. Conclusion: This study showed very few complications among intrauterine device users, and high continuation and satisfaction rates. The intrauterine device is a long-acting, effective, reversible and safe contraceptive that can be used by most women for birth spacing in Guinea, where women do not regularly visit health facilities.
文摘Impacts of grid architectures on temporal diffusion of PV-based communal grids (community owned minigrids or microgrids) in a rural developing community are modelled and simulated using MATLAB/Simulink and a survey-informed agent-based model (ABM) developed in NetLogo. Results show that decentralised control architectures stimulate minigrid formations and connections by allowing easy expansions of the minigrids as each decentralised PV system within a minigrid is treated equally and determines its own real and reactive power, eliminating the need for communication links. This also reduces the cost of implementing such a system;fewer connections are realized with centralised controls as such systems require high speed communication links which make them both difficult to expand and expensive to implement. Results also show that multi-master operation modes lead to more communal grid connections compared to single-master operation modes because in the former, all distributed PV systems within a communal grid have the same rank and can act as masters or can be operated as combinations of master generators (VSIs) and PQ inverters, allowing for more design flexibility and easy connections from potential customers.
文摘The paper presents a cognitive science framework for the analysis of knowledge-based systems,including people, media. simulation and expert systems, resulting in a practical model for the procedures ofknowledge engineering. Starting with the construct of a social organization model driven by anticipationand thed differentiating this into pesonal scientists with diverse relations to people and their internal andexternal communication, it provides powerful and general model of society. people, and the roles of peoplein society. This model extends naturally ic the role of conventional media in the knowledge processes ofsociety and the new roles of computer-based simulation and expert systems. In particular it provides amodel of knowledge transfer that enables the processes of knowledge engineering to be analyzed andautomated.
文摘This study aimed at identifying the most preferred water quality tracking system (WQTS) for adoption and the determining factors for the same among the Langata sub County households in Nairobi city, Kenya. Perrenial municipal water shortage in this neighborhood has forced the residents to depend on vended water supplication but whose quality is not possible to verify at the moment. Accordingly, a mobile phone quality tracing application running on blockchain technology platform was developed to fill the gap of provenance tracking. A non-market discrete choice experiments (DCEs) model was deployed in which four-option attribute bundles;with one being the “status quo” choice were presented to each of the 382 randomly sampled respondents from the five wards within the area. Results indicated that Option 2;the communally managed WQTS emerged as the most preferred choice at 53.9%. Secondly, the male factor was identified as the major determinant to this decision. In conclusion, the study proposes for the installation of this new WQTS which will trigger a 12% adjustment of the average household’s monthly water bill. In addition, this paper recommends for a city-wide assessment of residents’ willingness to pay (WTP) for this WQTS, which it deems as an improved response to water shortage problem. Finally, the study contributes to the application of DCEs model in technology adoption literature.
文摘Collection of Municipal Solid Waste (MSW) is important in every waste management program. Communal container collection systems appear most prevalent in many developing countries. However, this collection system is associated with problems such as overflow of waste containers, ground dumping at collection sites, and open/indiscriminate dumping at unauthorized places. The spatial distribution of these activities present potential contamination challenges to water resources. Spatial information on Municipal Solid Waste Collection/Dump Sites (MSWCS) is essential for Municipal Solid Waste Management (MSWM) decision-making, including siting and collection route planning, and dumps cleanup. Integration of Geographic Information Systems (GIS) and Global Positioning Systems (GPS) present a platform to capture, map, and analyze spatial MSWM issues. This study applied GIS and GPS technologies to map MSWCS in Wa town, Ghana. Wa Municipality waste collection system efficiency was analyzed based on spatial availability of communal containers. A GIS model was developed and used to analyze proximity of MSWCS to boreholes drinking water sources. A pollution risk map was also developed to analyze the potential impact of indiscriminate dumps on hand-dug wells and surface water in Wa. The results reveal poor management in a significant number (about 67%) of MSWCS sites. Fifteen percent of mechanized boreholes failed the minimum proximity requirement (≥100 m) of the model. This study findings illustrate that MSWM in developing countries may be improved using GIS and GPS technologies. The approach used for Wa could be replicated in other towns in Ghana and other developing nations with similar MSWM problems to enhance policy and management decision-making.
文摘West African Dwarf (WAD) goats represent one of the predominant small ruminant breeds raised by resource-limited households in southern Nigeria as well as in the humid west and central Africa. This breed of goats is renowned for its adaptation to hot and humid environments, high fertility and prolificacy under backyard systems where they are raised almost with zero investment. On account of its contributions to household income and food security in southern Nigeria, there is the need for a detailed phenotypic and genetic characterization as well as the design of breeding strategies for its conservation through sustainable utilization. A critical challenge, however, is that there are no national breeding policies in most of the countries where WAD goats are raised. The objectives of this paper are: to review literature reports on trait-level information and estimates of genetic parameters for some economic characters of WAD goats;and to discuss a communal breeding scheme for its conservation through sustainable utilization. The presentation shows that WAD goats represent a highly diverse population, with particular reference to qualitative and performance-related traits, reflecting the role of traditional institutions in the maintenance of animal diversity in local populations. A genetic improvement programme involving dispersed open nucleus breeding scheme was discussed. The scheme involves backyard WAD goat units in villages as base population and dispersed communally managed schemes that maintain a population of bucks only, as nucleus units. Critical issues such as the definition of breeding goals by farmers, as well as communal project ownership, are emphasized. The ultimate goal of the breeding programme is to create opportunities for community-based management of WAD goat genetic resources for the benefit of backyard goat farmers in the region.
文摘In this paper power electronics used in PV power generation systems have been reviewed and modelled. PV systems need converters for maximum power point tracking, power conditioning, voltage step-up/down as necessary, and for storage charge-controlling. Inverters are needed for AC loads and for utility grid interfacing. The four basic DC-DC converters commonly used with PV systems have been reviewed and modelled. Different DC-AC inverter types and operational architectures have also been reviewed with the two-stage DC-AC inverter, with the point of common coupling (PCC) at the inverter input, suggested as the most cost-effective and efficient architecture for PV-based communal grids. This is because only one inverter is used for the entire system as opposed to an inverter for every module string, resulting in higher efficiencies, low cost, and low harmonic distortions when compared to systems with PCC at AC terminal. The aim of power conversion/inversion is to extract maximum power possible from the PV system and where necessary, to invert it at close to 100% as possible. Highlight: 1) DC-DC converters are necessary for power conditioning in PV systems;2) DC-AC inverters are necessary for AC loads and for utility grid interfacing;3) DC-AC inverters are also used to control the PV systems when grid connected;4) Best inverter configuration cost-effectively and efficiently allows easy system modifications.
文摘Vitality is a quality that makes a public space operational and attractive throughout the day in relation to ongoing activities. This parameter can be evaluated through measures such as collective people presence, mixed-use functions, diversity of activities, and other related supportive physical elements. The aim of this research is to evaluate women＇s communal life in terms of vitality measures within public spaces. The commercial setting of Isfahan’s traditional bazaar was selected as the study area. To enhance the credibility of the results, several data collection methods, for example, semi-structured individual interviews （n = 24）, semi-structured focused group interviews （five groups including 28 middle-aged women）, direct observation, snap photography, and unobtrusive behavioral observation of women in communal life within the selected study area, were employed. To analyze the collected data, qualitative content and descriptive analyses were used. Our results indicate that by increasing the vitality of a public space through its related measures, women＇s presence will grow, and through this growth, the quality of their communal life would be enhanced.
文摘Gas emissions are produced by each economic entity individually—whether they are a large industrial enterprise, a boiler-house or a household (dwelling house). At that, in addition to visible chimneys, there are a lot of hidden (unrecorded) sources of emissions in form of ventilation branch pipes. Communal systems for removal and reprocessing of wastes of two types: liquid (municipal sewage lines) and solid (collection and removal of wastes) are operated in populated localities. For the third type of waste—gaseous—a similarly municipal structure does not exist. For the time being there is no possibility for full system control and neutralization of dust and gas wastes because there is no system in the physical form which would enable comprehensive receipt of exit gases from all the city sources for further processing thereof. It is for the first time when a principally new holistic approach to cleaning/treatment of all city dust and gas emissions (wastes) is proposed which consists in creation of a City Communal Aspiration System (Municipal Aspiration System) containing a city communal aspiration network (gas outlets) for receipt/transportation of exhaust (flue) gases and a plant for utilization of such wastes connected to such network. In other words, it is proposed to organize a “City without Chimneys”. The proposed solution permits to remove mass unsystematic and uncontrolled emissions of environmentally harmful gas wastes in cities, reduce climate risks and make the transition to a new level of organization of environmental planning and management and, therefore, eliminates or principally simplifies many ecological difficulties and restrictions in urban planning (inseparably related to ecology) in sanitary rules and standards.
文摘<span style="font-family:Verdana;">Body weight is a crucial trait that aids farmers in decision-making regarding vaccinations, feeding, marketing and selection during the breeding programs. The study was conducted to investigate the effect of sex and age on body weight (BW), body condition score (BCS) and some blood biochemical parameters (BBP) and to determine the correlation amongst BW, BCS and BBP of non-descriptive goats at Santombe communal farming system. Blood samples were collected from 33 apparently healthy goats (27 females and 6 males) aged 6 - 8 tooth with a mean BW (32.62 ± 11.39 kg) while BCS (3.17 ± 0.39) was taken by means of palpating the lumbar area, sternum and the ribs. The BCS was rated on a scale of 1 to 5 with 1 being emaciated and 5 being extremely fat. The blood samples were analyzed using Cobas intergra 400 plus </span>che<span style="font-family:Verdana;">mistry analyzer, Roche for biochemical parameters such as total protein (TP), urea, cholesterol (Chol), magnesium (Mg), phosphorous (P) and calcium (Ca) with mean values of 72.79 ± 5.84 mg/l, 2.76 ± 1.16 mmol/l, 2.08 ± 0.40 mmol/l, 1.09 ± 0.09 mmol/l, 2.30 ± 0.49 mmol/l and 2.45 ± 0.12 mmol/l respectively. Sex and age had significant effects on BW, BCS and some biochemical parameters. The BW and BCS for males were significantly higher than for females. Correlation results indicated that BW had a positive relationship with BCS (r = 0.677), TP and BW (r = 0.400), Chol and BCS (r = 0.4025) and Mg and TP (r = -0.075). Age and sex had significant influences on BW, BCS and some blood biochemical parameters. Consideration of the factors can aid in determining the accurate diagnosis of the nutritional status of goats.</span>
文摘Different droop control methods for PV-based communal grid networks (minigrids and microgrids) with different line resistances (R) and impedances (X) are modelled and simulated in MATLAB to determine the most efficient control method for a given network. Results show that active power-frequency (P-f) droop control method is the most efficient for low voltage transmission networks with low X/R ratios while reactive power-voltage (Q-V) droop control method is the most efficient for systems with high X/R ratios. For systems with complex line resistances and impedances, i.e. near unity X/R ratios, P-f or Q-V droop methods cannot individually efficiently regulate line voltage and frequency. For such systems, P-Q-f droop control method, where both active and reactive power could be used to control PCC voltage via shunt-connected inverters, is determined to be the most efficient control method. Results also show that shunt-connection of inverters leads to improved power flow control of interconnected communal grids by allowing feeder voltage regulation, load reactive power support, reactive power management between feeders, and improved overall system performance against dynamic disturbances.
文摘Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.
文摘An integral part of risk assessment for natural hazards, communal vulnerability assessment (CVA) is now receiving considerable attention, with the on-going International Decade of Natural Disaster Reduction (IDNDR). This article expounds the definition of the CVA concept and its implication. In addition, it offers a brief discussion of the reasons why CVA has been neglected and its relationship with socio-economic and physical vulnerability assessment. The article also gives an explorative exposition of the methodology and application of communal vulnerability analysis in risk reduction.
文摘Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains-（1） system operation performance; （2） agricultural productivity and economics; （3） financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute （IWMI） and Food and Agriculture Organization （FAO）. Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System （MARI1S）, Lucban, Garab and Divisoria Communal Irrigation Systems （CIS）, respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m3, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.
