Strict Control Strategies Research Articles

On reliability of annotations in contextual emotion imagery

We documented the relabeling process for a subset of a renowned database for emotion-in-context recognition, with the aim of promoting reliability in final labels. To this end, emotion categories were organized into eight groups, while a large number of participants was requested for tagging. A strict control strategy was performed along the experiments, whose duration was 13.45 minutes average per day. Annotators were free to participate in any of the daily experiments (the average number of participants was 28), and a Z-Score filtering technique was implemented to keep trustworthiness of annotations. As a result, the value of the agreement parameter Fleiss’ Kapa increasingly varied from slight to almost perfect, revealing a coherent diversity of the experiments. Our results support the hypothesis that a small number of categories and a large number of voters benefit reliability of annotations in contextual emotion imagery.

BlaTEM-positive Salmonella enterica serovars Agona and Derby are prevalent among food-producing animals in Chongqing, China.

Salmonella is one of the most important foodborne zoonotic pathogens, causing global morbidity and mortality in both humans and animals. Due to the extensive use of antimicrobials in food-producing animals, the antimicrobial resistance of Salmonella has attracted increasing attention globally. There have been many reports concerning the antimicrobial resistance of Salmonella from food-producing animals, meats and the environment. However, few studies on Salmonella from food-producing animals have been reported in Chongqing municipality, China. The aim of the present study was to determine the prevalence, serovar diversity, sequence types, and antimicrobial resistance of Salmonella isolated from livestock and poultry in Chongqing. Meanwhile, we also want to know the presence of β-lactamase genes, plasmid-mediated quinolone resistance (PMQR) genes and quinolone resistance-determining region (QRDR) mutations of Salmonella isolates. A total of 129 Salmonella strains were recovered from 2,500 fecal samples at 41 farms from pigs, goats, beef cattle, rabbits, chickens, and ducks. Fourteen serovars were identified, with S. Agona and S. Derby being the dominant serovars. The 129 isolates had high resistance to doxycycline (87.6%), ampicillin (80.6%), tetracycline (79.8%), trimethoprim (77.5%), florfenicol (76.7%) chloramphenicol (72.9%), and trimethoprim-sulfamethoxazole (71.3%), but were susceptible to cefepime. A total of 114 (88.4%) isolates showed multidrug resistant phenotypes. The prevalence of β-lactamase genes in Salmonella isolates was 89.9% (116/129), and among these isolates, 107 (82.9%) harbored blaTEM, followed by blaOXA (26, 20.2%), blaCTX-M (8, 6.2%), and blaCMY (3, 2.3%). In addition, qnrB, qnrD, qnrS, oqxA, oqxB, and aac(6')-Ib-cr were detected in 11, 2, 34, 34, 43, and 72 PMQR-producing isolates, respectively. Moreover, QRDR mutations were very common in PMQR-positive Salmonella isolates (97.2%, 70/72) with mutation(s) in parC or combinative mutations in gyrA and parC. More significantly, 32 extended spectrum beta-lactamase (ESBL)-producing isolates were identified, and 62.5% of them were found to harbor one to four PMQR genes. Furthermore, 11 sequence types were identified from the isolates, and most of ESBL-producing isolates were attributed to ST34 (15.6%) and ST40 (62.5%). The coexistence of PMQR genes with β-lactamase genes and the extensive mutations in QRDR present in Salmonella isolates from food-producing animals suggest a potential threat to public health. Reasonable utilization and strict control strategies for antimicrobials in animal husbandry and animal treatment are necessary to reduce the emergence and dissemination of drug-resistant Salmonella isolates.

Characteristics, sources and health risk assessment of atmospheric carbonyls during multiple ozone pollution episodes in urban Beijing: Insights into control strategies

Carbonyls have attracted continuous attention due to their critical roles in atmospheric chemistry and their potential hazards to the ecological environment and human health. In this study, atmospheric carbonyls were measured during several ground-level-ozone (O3) pollution episodes at three urban sites (CRAES, IEP and BJUT) in Beijing in 2019 and 2020. Comparative analysis revealed that the carbonyl concentrations were 20.25 ± 6.91 ppb and 13.43 ± 5.13 ppb in 2019 and 2020 in Beijing, respectively, with a significant spatial trend from north to south, and carbonyl levels in urban Beijing were in an upper-intermediate range in China, and higher than those in other countries reported in the literature. A particularly noteworthy phenomenon is the consistency of carbonyl concentrations with variations in O3 concentrations. On O3 polluted days, the carbonyl concentrations were 1.3–1.5 times higher than those on non-O3 polluted days. Secondary formation contributed more to formaldehyde (FA) and acetaldehyde (AA) on O3 polluted days, while the anthropogenic emissions were more significant for acetone (AC) on non-O3 polluted days. Vehicle exhaust and solvent utilization were the main primary contributors to carbonyls. Due to reduced anthropogenic emissions caused by the COVID-19 lockdown and the “Program for Controlling Volatile Organic Compounds in 2020” in China, the contributions of primary emissions to carbonyls decreased in 2020 in Beijing. Human cancer risks to exposed populations from FA and AA increased with elevated O3 levels, and the risks still remained on non-O3 polluted days. The residents around the BJUT site might experience relatively higher human cancer risks than those around the other two sites. The findings in this study confirmed that atmospheric carbonyl pollution and its potential human health hazards cannot be ignored in urban Beijing; therefore, more strict control strategies for atmospheric carbonyls are urgently needed to better protect human health in Beijing in the future.

Epidemiological characteristics of imported cases of COVID-19 from association of southeast Asian nations countries to China

Objective To understand the epidemiological characteristics of imported coronavirus disease 2019 (COVID-19) cases from Association of Southeast Asian Nations (ASEAN) countries in China from January 1, 2020 to February 28, 2021, and provide evidence for the improvement of China's strategy of COVID-19 control towards travelers from ASEAN countries. Methods Data were obtained from the National Infectious Disease Reporting Information Management System of China Disease Prevention and Control Information System and the World Health Organization (WHO) website. The socio-demographic characteristics, clinical types, temporal, spatial and population distributions of the imported COVID-19 cases from ASEAN countries in China were analyzed by descriptive epidemiological methods. Results From January 2020 to February 2021, a total 1 585 imported COVID-19 cases from ASEAN countries were reported in China, accounting for 18.51% of total imported cases in China. The sex ratio of the imported COVID-19 cases was 3.95:1. The average age of the cases was (35.21±11.09) years. Workers, house workers and people engaged in business service were the top 3 populations affected, with the proportions of 21.26%, 13.56% and 12.93%, respectively. The majority of imported cases were asymptomatic (921 cases, 58.11%), the others were pneumonia cases (407 cases, 25.68%) and mild cases (256 cases, 16.15%). The incidence peak of imported COVID-19 cases occurred during August - October, 2020 (940 cases, 59.46%). The main source countries were the Philippines (775 cases, 48.90%), Indonesia (301 cases, 18.99%) and Singapore (279 cases, 17.60%). The cases were distributed in 24 provinces and municipalities. Guangdong (420 cases, 26.50%), Fujian (255 cases, 16.09%) and Shanghai (137 cases, 8.64%) were the top 3 areas. There were 83.85% of the imported cases diagnosed within three days after onset. Conclusion The majority of the imported COVID-19 cases in China from ASEAN countries were male young adults with asymptomatic infections. Given that the spread risk of COVID-19 from ASEAN countries might exist for a long time, all the entry points of China should continue the current strict control strategy to prevent community spread caused by imported COVID-19 cases.

Spatiotemporal Dynamics of Highly Pathogenic Avian Influenza Subtype H5N8 in Poultry Farms, South Korea

Highly pathogenic avian influenza (HPAI), a zoonotic disease, is a major threat to humans and poultry health worldwide. In January 2014, HPAI virus subtype H5N8 first infected poultry farms in South Korea, and 393 outbreaks, overall, were reported with enormous economic damage in the poultry industry. We analyzed the spatiotemporal distribution of HPAI H5N8 outbreaks in poultry farms using the global and local spatiotemporal interaction analyses in the first (January to July 2014) and second (September 2014 to June 2015) outbreak waves. The space–time K-function analyses revealed significant interactions within three days and in an over-40 km space–time window between the two study periods. The excess risk attributable value (D0) was maintained despite the distance in the case of HPAI H5N8 in South Korea. Eleven spatiotemporal clusters were identified, and the results showed that the HPAI introduction was from the southwestern region, and spread to the middle region, in South Korea. This spatiotemporal interaction indicates that the HPAI epidemic in South Korea was mostly characterized by short period transmission, regardless of the distance. This finding supports strict control strategies such as preemptive depopulation, and poultry movement tracking. Further studies are needed to understand HPAI disease transmission patterns.

The 2015 and 2016 wintertime air pollution in China: SO<sub>2</sub> emission changes derived from a WRF-Chem/EnKF coupled data assimilation system

Abstract. Ambient pollutants and emissions in China have changed significantly in recent years due to strict control strategies implemented by the government. It is of great interest to evaluate the reduction of emissions and the air quality response using a data assimilation (DA) approach. In this study, we updated the WRF-Chem/EnKF (Weather Research and Forecasting – WRF, model coupled with the chemistry/ensemble Kalman filter – Chem/EnKF) system to directly analyze SO2 emissions instead of using emission scaling factors, as in our previous study. Our purpose is to investigate whether the WRF-Chem/EnKF system is capable of detecting the emission deficiencies in the bottom-up emission inventory (2010-MEIC, Multi-resolution Emission Inventory for China), dynamically updating the spatial–temporal emission changes (2010 to 2015/2016) and, most importantly, locating the “new” (emerging) emission sources that are not considered in the a priori emission inventory. The 2010 January MEIC emission inventory was used as the a priori inventory (to generate background emission fields). The 2015 and 2016 January emissions were obtained by assimilating the hourly surface SO2 concentration observations for January 2015 and 2016. The SO2 emission changes for northern, western, and southern China from 2010 to 2015 and from 2015 to 2016 (for the month of January) from the EnSRF (ensemble square root filter) approach were investigated, and the emission control strategies during the corresponding period were discussed. The January 2010–2015 differences showed inhomogeneous change patterns in different regions, including (1) significant emission reductions in southern China; (2) significant emission reductions in larger cities with a wide increase in the surrounding suburban and rural regions in northern China, which may indicate missing raw coal combustion for winter heating that was not taken into account in the a priori emission inventory; and (3) significantly large emission increases in western China due to the energy expansion strategy. The January 2015–2016 differences showed wide emission reductions from 2015 to 2016, indicating stricter control strategies having been fully executed nationwide. These derived emission changes coincided with the period of the energy development national strategy in northwestern China and the regulations for the reduction of SO2 emissions, indicating that the updated DA system was possibly capable of detecting emission deficiencies, dynamically updating the spatial–temporal emission changes (2010 to 2015/2016), and locating newly added sources. Forecast experiments using the a priori and updated emissions were conducted. Comparisons showed improvements from using updated emissions. The improvements in southern China were much larger than those in northern and western China. For the Sichuan Basin, central China, the Yangtze River Delta, and the Pearl River Delta, the BIAS (bias, equal to the difference between the modeled value and the observational value, representing the overall model tendency) decreased by 61.8 %–78.2 % (for different regions), the RMSE decreased by 27.9 %–52.2 %, and CORR values (correlation coefficient, equal to the linear relationship between the modeled values and the observational values) increased by 12.5 %–47.1 %. The limitation of the study is that the analyzed emissions are still model-dependent, as the ensembles are conducted using the WRF-Chem model; therefore, the performances of the ensembles are model-dependent. Our study indicated that the WRF-Chem/EnSRF system is not only capable of improving the emissions and forecasts in the model but can also evaluate realistic emission changes. Thus, it is possible to apply the system for the evaluation of emission changes in the future.

High-time-resolution source apportionment of PM<sub>2.5</sub> in Beijing with multiple models

Abstract. Beijing has suffered from heavy local emissions as well as regional transport of air pollutants, resulting in severe atmospheric fine-particle (PM2.5) pollution. This study developed a combined method to investigate source types of PM2.5 and its source regions during winter 2016 in Beijing, which include the receptor model (positive matrix factorization, PMF), footprint and an air quality model. The PMF model was performed with high-time-resolution measurements of trace elements, water soluble ions, organic carbon and elemental carbon using online instruments during the wintertime campaign of the Air Pollution and Human Health in a Chinese Megacity – Beijing (APHH-Beijing) program in 2016. Source types and their contributions estimated by PMF model using online measurements were linked with source regions identified by the footprint model, and the regional transport contribution was estimated by an air quality model (the Nested Air Quality Prediction Model System, NAQPMS) to analyze the specific sources and source regions during haze episodes. Our results show that secondary and biomass-burning sources were dominated by regional transport, while the coal combustion source increased with local contribution, suggesting that strict control strategies for local coal combustion in Beijing and a reduction of biomass-burning and gaseous precursor emissions in surrounding areas were essential to improve air quality in Beijing. The combination of PMF with footprint results revealed that secondary sources were mainly associated with southern footprints (53 %). The northern footprint was characterized by a high dust source contribution (11 %), while industrial sources increased with the eastern footprint (10 %). The results demonstrated the power of combining receptor model-based source apportionment with other models in understanding the formation of haze episodes and identifying specific sources from different source regions affecting air quality in Beijing.

Karakteristik morfologi dan sebaran tipe kawin Phytophthora capsici asal lada di Pulau Jawa

Morphology characters and mating types distribution of Phytophthora capsici from black pepper in Java IslandPepper (Piper nigrum) is one of the most important spice crops in Indonesia. Recently its production declining due to infection of foot rot disease caused by Phytophthora capsici. This pathogen has two different mating types, namely A1 and A2, in which the presence of opposite two mating types is important for sexual reproduction and formation of oospores. The movement of pepper seedling from one area to another is highly facilitated alteration of mating type distribution map of P. capsici. The objectives of this research were to determine the morphological characteristics and the spread of mating types of P. capsici in Java. Morphology characters of P. capsici isolates were indicated by variation in sporangial size and shape, as well as types of colony appearance. The length (l) and width (w) of sporangium were in the range of 15.1–76.2 µm and 9.8–44.8 µm, respectively; while the l/w ratio was 1.12–2.27. Mating type assay showed that A2 type was more dominantly found than A1 type. This study found two different mating types present in the same area, i.e. Regency of Pacitan (East Java) and Regency of Sleman (Special Region of Yogyakarta). The findings of this research suggested that it is required more strict control strategy on the mobilization of black pepper seedling particularly in the area where the certain mating type is not found yet so that the emergence of new more virulent genotype of pathogen can be prevented.

Induction of arthritis in chickens by infection with novel virulent Salmonella Pullorum strains

Salmonella enterica subsp. enterica serovar Gallinarum biovar Pullorum (Salmonella Pullorum) is a host-specific serovar causing systemic infection with high mortality in young chicks. Pullorum disease is characterized by white diarrhea. However, arthritis has become increasingly frequent recently, particularly in southern China. The aim of the present study was to determine the pathogenesis and arthritis induction of new Salmonella Pullorum isolates. We isolated and identified five Salmonella Pullorum strains from broilers with bacterial arthritis and lameness in a commercial poultry farm. Four of five isolates were resistant to at least three classes of antibiotics and were defined as multidrug-resistant Salmonella Pullorum. All isolates had the same CRISPR sequence type and belonged to a single major cluster. The isolates exhibited high capability of biofilm formation, which may facilitate their dispersal and survival in hostile habitats, and showed high virulence based on embryo lethality and inoculation of newly hatched chicks. Tissue distribution analysis confirmed that SP1621 was more adapted to colonize the joint when compared to the white diarrhoea-causing Salmonella Pullorum reference strain S06004. Reproducible arthritis and typical joint lesions were observed in SP1621-infected chicks, and histopathological examination showed necrotic synovitis and cartilage tissue hyperplasia of the joint. Koch’s postulates were confirmed when the novel Salmonella Pullorum strain was re-isolated from the joint tissues of experimentally inoculated chicks. These novel Salmonella Pullorum isolates have unique ability to induce arthritis in chickens, representing expanded pathogenic diversity in China. These results suggest the need for strict control strategies and new vaccines to prevent the disease.

Spatio-temporal patterns of highly pathogenic avian influenza virus subtype H5N8 spread, France, 2016 to 2017.

IntroductionFrance is one of Europe’s foremost poultry producers and the world’s fifth largest producer of poultry meat. In November 2016, highly pathogenic avian influenza (HPAI) virus subtype H5N8 emerged in poultry in the country. As of 23 March 2017, a total of 484 confirmed outbreaks were reported, with consequences on animal health and socio-economic impacts for producers. Methods: We examined the spatio-temporal distribution of outbreaks that occurred in France between November 2016 and March 2017, using the space–time K-function and space–time permutation model of the scan statistic test. Results: Most outbreaks affected duck flocks in south-west France. A significant space–time interaction of outbreaks was present at the beginning of the epidemic within a window of 8 km and 13 days. This interaction disappeared towards the epidemic end. Five spatio-temporal outbreak clusters were identified in the main poultry producing areas, moving sequentially from east to west. The average spread rate of the epidemic front wave was estimated to be 5.5 km/week. It increased from February 2017 and was negatively associated with the duck holding density. Conclusion: HPAI-H5N8 infections varied over time and space in France. Intense transmission events occurred at the early stages of the epidemic, followed by long-range jumps in the disease spread towards its end. Findings support strict control strategies in poultry production as well as the maintenance of high biosecurity standards for poultry holdings. Factors and mechanisms driving HPAI spread need to be further investigated.

Economic impacts from PM2.5 pollution-related health effects in China's road transport sector: A provincial-level analysis

Economic impact assessments of air pollution-related health effects from a sectoral perspective in China is still deficient. This study evaluates the PM2.5 pollution-related health impacts of the road transport sector on China's economy at both national and provincial levels in 2030 under various air mitigation technologies scenarios. Health impacts are estimated using an integrated approach that combines the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model, a computable general equilibrium (CGE) model and a health model. Results show that at a national level, the road transport sector leads to 163.64 thousand deaths per year, increases the per capita risk of morbidity by 0.37% and accounts for 1.43 billion Yuan in health care expenditures. We estimate 442.90 billion Yuan of the value of statistical life loss and 2.09 h/capita of work time loss in 2015. Without additional control measures, air pollution related to the transport sector will cause 177.50 thousand deaths in 2030, a 0.40% per capita increase in the risk of morbidity, accounting for 4.12 billion Yuan in health care expenditures, 737.15 billion Yuan of statistical life loss and 2.23 h/capita of work time loss. Based on our model, implementing the most strict control strategy scenario would decrease mortality by 42.14%, morbidity risk by 42.14%, health care expenditures by 41.94%, statistical life loss by 26.22% and hours of work time loss by 42.65%, comparing with the no control measure scenario. In addition, PM2.5 pollution from the road transport sector will cause 0.68% GDP loss in 2030. At a provincial level, GDP losses in 14 out of 30 provinces far exceed the national rate. Henan (1.20%), Sichuan (1.07%), Chongqing (0.99%), Hubei (0.94%), and Shandong (0.90%) would experience the highest GDP loss in 2030. Implementing control strategies to reduce PM2.5 pollution in the road transport sector could bring positive benefits in half of the Chinese provinces especially in provinces that suffer greater health impacts from the road transport sector (such as Henan and Sichuan).

Review of parasitic zoonotic infections in Egypt

Zoonoses are diseases and infections that are transmitted in nature between vertebrates and humans. Zoonoses consist of an interaction among at least three species: one pathogen and two hosts − animals and humans. This review aimed at shedding in depth light on zoonotic parasitic diseases in Egypt, with special reference to their relative incidence between humans, reservoir animals, sources of human infection and control policies. According to the available literature, many parasitic zoonoses are endemic in Egypt. In rural areas, intestinal parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children. Some parasitic zoonoses are mainly found in certain areas in Egypt, for example, cutaneous leishmaniasis and zoonotic babesiosis in Sinai. Other locations in Egypt have a history of certain parasitic zoonoses, such as visceral leishmaniasis in the El Agamy area in Alexandria. Fortunately, control programs have led to a dramatic decrease in the prevalence of other zoonoses, such as intestinal schistosomiasis and fascioliasis in the country. In Egypt, animal reservoirs of parasitic zoonoses have been identified. These include rodents, stray dogs, and cats as well as domestic and farm animals and birds. Many vectors have also been revealed, typically mosquitoes and ticks, which pose real threats for disease transmission. Strict control strategies are needed to upgrade and complement current efforts at eradicating parasitic zoonoses in Egypt.

Set organic pollution as an impact category to achieve more comprehensive evaluation of life cycle assessment in wastewater-related issues.

For wastewater-related issues (WRI), life cycle assessment (LCA) is often used to evaluate environmental impacts and derive optimization strategies. To promote the application of LCA for WRI, it is critical to incorporate local impact of water pollutants. Organic pollution, a main type of water pollution, has not been given much consideration in current LCA systems. This paper investigates the necessity of setting a regionalized impact category to reflect the local impact of organic pollution. A case study is conducted concerning an upgraded wastewater treatment plant (WWTP) in China, which is assumed to meet different sewage control strategies. Chemical oxygen demand (COD) is selected to represent the organic pollution and treated as an individual impact category. CML 2002 is used to quantify the environmental impacts of different strategies. Results show that abnormal LCA results are generated with the traditional eutrophication impact category, and after the introduction of COD, more reasonable LCA results are obtained, making the entire comparison of different control strategies more meaningful and compelling. Moreover, BEES, Ecovalue 08, and Chinese factors are adopted here as different weighting methods. Different weighting results exhibited various trade-offs for the increasingly strict control strategies; the results of BEES and Ecovalue08 underlined the potential environmental burden, but the results of Chinese factors only emphasized the local environmental improvement. It is concluded that setting regionalized impact category for organic pollution can make LCA results more reasonable in wastewater treatment, especially in evaluating Chinese cases because of the serious water pollution caused by large quantities of COD emission.

Evaluation of chili germplasm for resistance to bacterial wilt caused by Ralstonia solanacearum

Bacterial wilt incited by Ralstonia solanacearum is a serious threat to economically important crops throughout the world and warrants strict control strategies. Use of resistant cultivars is one of the most important strategies to dispense with the pernicious consequences of chemicals. In the present study, twenty eight chili cultivars were assessed for their relative resistance or susceptibility to a highly virulent strain of R. solanacearum biovar 3 (RsBd6). Two cultivars namely Skyline-II and Hifly appeared highly resistant. Sanam was the only cultivar found to be resistant while twelve cultivars were categorized as moderately resistant to the bacterium. On the other hand, seven cultivars were rated as moderately susceptible and three showed susceptible reaction. Two cultivars, Talhari and Maxi, behaved as highly susceptible and California Wonder was found to be extremely susceptible. In susceptible cultivars, symptoms appeared 4 days after inoculation resulting in complete wilting within 14 days while in resistant and moderately resistant cultivars, no wilting was observed even after 14 days of inoculation. Brown discoloration in vascular systems of highly susceptible plants was also observed. The resistant and moderately resistant cultivars are therefore recommended for cultivation and in developing new resistant chili cultivars.

Prevalence of brucellosis in small ruminants in three regions of Ghana

Summary Jarikre, T. A., B. O. Emikpe, R. D. Folitse, T. K. Odoom, A. Fuseini & E. Shaibu, 2014. Prevalence of brucellosis in small ruminants in three regions of G hana. Bulg. J. Vet. Med. (online first). Information on the prevalenc e of important reproductive zoonoses in West African countries other than Nigeria had been scanty in literature. This study estimates the prevalence of brucellosis in sheep and goats from Northern, Ashanti and Greater Accra regions of Ghana . T issues/swabs (319) and s erum (370) samples were collected from sheep and goats comprising male and f e male West African Dwarf (WAD) and S ahelian breeds between 1 to 4 years of age in the regions. These were screened for brucellosis using Mod i fied Ziehl Neelsen (MZN) sta ining method and the Rose Bengal Plate Test (RBPT). A seroprevalence of 13.3% was recorded while 17.0% were positive with modified ZN stai n ing. Goats (10%) and female animals (7.0%) had slightly high er seroprevalence. Adult animals of above two years had p rev a lence of 92.0% while WAD breed had the highest prevalence of 63.0% with 2.7% in female WAD. More seropositive animals were found from Ashanti region than other regions. Due to the zoonotic and economic implications of the disease, there is the need to e m bark on the strict control strategies i n cluding vaccination of small ruminants against brucellosis.

Economic and financial aspects of mine closure

AbstractToday, mine reclamation is a key component to a successful mine plan. Most of the industrialized nations have recognized the need to make mining activities relatively environmentally friendly, if they want to continue to benefit from the economic gains from mineral resource development. Countries such as the United States, Canada, Australia and South Africa are leaders in the field and have implemented relatively sophisticated legislation to ensure environmentally correct mine closure. These countries rely on a combination of strict control strategies and economic penalties to ensure compliance.Yet, from the firm's perspective, reclamation activities are counterproductive as they cut into profits. In order to attract economic development and earn much needed economic capital, most of the rest of the world, particularly the developing countries, lack effective mine closure legislation. The traditional command and control type of legislation that is sometimes used is either vague and therefore avoided, or not enforced appropriately, resulting in an undesirable level of environmental degradation.With the use of case studies from Brazil, this article shows that direct controls are effective in some instances and not in others. It proposes that economic and financial tools may be more effective than the traditional direct controls in getting firms to comply with environmental standards, particularly in developing countries where environmental compliance is more difficult to achieve. It explains the use of performance bonding as one type of economic incentive that has proven to be an effective environmental policy in mine planning and closure.The authors additionally push beyond the typical style of performance bonds to introduce a flexible bonding and insurance system that allows governments to maintain strict environmental standards but limits firms financial exposure during the mining process. Such a system learns from the successes of the industrialized countries that use performance bonding and is sensitive to the needs of developing nations to attract investment yet maintain environmental integrity.

Analysis of the Steady State Performance of the Double Output Induction Generator

The steady-state performance of the variable speed constant frequency double output induction generator (VSCF-DOIG) is investigated. The generator is subjected to a strict control strategy in which the stator current is kept constant and equal to its rated value. This allows the generator to deliver rated power from its stator terminals, while from its rotor terminals a variable power output is obtained that is proportional to its rotor speed. Thus more than rated power can be extracted from the induction machine without overheating. The theoretical results of this investigation are verified experimentally.

Analysis of the Steady State Performance of the Double Output Induction Generator

The steady-state performance of the variable speed constant frequency double output induction generator (VSCF-DOIG) is investigated. The generator is subjected to a strict control strategy in which the stator current is kept constant and equal to its rated value. This allows the generator to deliver rated power from its stator terminals, while from its rotor terminals a variable power output is obtained that is proportional to its rotor speed. Thus more than rated power can be extracted from the induction machine without overheating. The theoretical results of this investigation are verified experimentally.