Cytochrome P450s(CYPs)are ubiquitously found in all kingdoms of life,playing important role in various biosynthetic pathways as well as degradative pathways;accordingly find applications in a vast variety of areas fro...Cytochrome P450s(CYPs)are ubiquitously found in all kingdoms of life,playing important role in various biosynthetic pathways as well as degradative pathways;accordingly find applications in a vast variety of areas from organic synthesis and drug metabolite production to modification of biomaterials and bioremediation.Significantly,CYPs catalyze chemically challenging CAH and CAC activation reactions using a reactive high-valent iron-oxo intermediate generated upon dioxygen activation at their heme center,while the other oxygen atom is reduced to the level of water by electrons provided through a reductase partner protein.Self-sufficient CYPs,encoding their heme domain and reductase protein in a single polypeptide,facilitate increased catalytic efficiency and render a less complicated system to work with.The self-sufficient CYP enzyme from CYP102A family(CYP102A1,BM3)is among the earliest and most-investigated model enzymes for mechanistic and structural studies as well as for biotechnological applications.An increasing number of self-sufficient CYPs from the same CYP102 family and from other families have also been reported in last decade.In this review,we introduce chemistry and biology of CYPs,followed by an overview of the characteristics of self-sufficient CYPs and representative reactions.Enzyme engineering efforts leading to novel self-sufficient CYP variants that can catalyze synthetically useful natural and non-natural(nature-mimicking)reactions are highlighted.Lastly,the strategy and efforts that aim to circumvent the challenges for improved thermostability,regio-and enantioselectivity,and total turnover number;associated with practical use of self-sufficient CYPs are reviewed.展开更多
One of the bottle-neck problems to the commercial development of supercritlcal water oxidation （SCWO） is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is a...One of the bottle-neck problems to the commercial development of supercritlcal water oxidation （SCWO） is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is analyzed. The reaction heat is recovered by means of Organic Rankine Circle. The process of SCWO for phenol is simulated with the Aspen Plus~ process simulator, and the results show that the influence of temperature on reaction heat is small at a constant pressure. It is reasonable to neglect the effect of temperature and to estimate the heat of reaction with average temperature when the temperature changes in a small range. The necessary condition to realize an energetically self-sufficient SCWO process is that the released energy is not less than consumed one. Whether a waste system with given chemical composition is energeticallyself-sufficient can be estimated by ^QR^QH 〉 W The thermodynamics analysis shows that energetically self-sufficient SCWO process with an Organic Rankine Cycle is a feasible technology for the recovery of SCWO reaction heat,and the energy balance point for phenol is 2wt%.展开更多
In recent research on image encryption,many schemes associate the key generation mechanism with the plaintext to resist chosen plaintext attacks.However,when the sender encrypts many images,a large amount of additiona...In recent research on image encryption,many schemes associate the key generation mechanism with the plaintext to resist chosen plaintext attacks.However,when the sender encrypts many images,a large amount of additional data related to the plaintext need to be transmitted,which leads to problems such as high transmission costs,high requirements for key storage space,and complex key management.Therefore,in this paper,we propose a self-sufficient plaintext-related JPEG image encryption scheme based on a unified key(SPJEU).This scheme establishes the connection between the plaintext and the key by selecting the direct current(DC)coefficients in the JPEG image through a unified key.Homomorphic encryption is applied to the selected DC coefficients,allowing plaintext information to be decrypted directly from the ciphertext domain using a specific calculation method.The remaining DC coefficients are encrypted through group diffusion,and the alternating current(AC)coefficients are grouped and permuted based on the run length.Extensive experiments show that our scheme can resist chosen plaintext attacks,avoid transmitting plaintext-related additional data in the communication channel,and simplify key management.This scheme also ensures the security and format compatibility of the ciphertext image,and the file increment after encryption is very small.展开更多
L-phenylglycine(L-phg)is a valuable non-proteinogenic amino acid used as a precursor to β-lactam antibiotics,antitumor agent taxol and many other pharmaceuticals.L-phg synthesis through microbial bioconversion allows...L-phenylglycine(L-phg)is a valuable non-proteinogenic amino acid used as a precursor to β-lactam antibiotics,antitumor agent taxol and many other pharmaceuticals.L-phg synthesis through microbial bioconversion allows for high enantioselectivity and sustainable production,which will be of great commercial and environmental value compared with organic synthesis methods.In this work,an L-phg synthesis pathway was built in Escher-ichia coli resulting in 0.23 mM L-phg production from 10 mM L-phenylalanine.Then,new hydroxymandelate synthases and hydroxymandelate oxidases were applied in the L-phg synthesis leading to a 5-fold increase in L-phg production.To address 2-oxoglutarate,NH_(4)^(+),and NADH shortage,a cofactor self-sufficient system was introduced,which converted by-product L-glutamate and NAD^(+)to these three cofactors simultaneously.In this way,L-phg increased 2.5-fold to 2.82 mM.Additionally,in order to reduce the loss of these three cofactors,a protein scaffold between synthesis pathway and cofactor regeneration modular was built,which further improved the L-phg production to 3.72 mM with a yield of 0.34 g/g L-phe.This work illustrated a strategy applying for whole-cell biocatalyst converting amino acid to its value-added chiral amine in a cofactor self-sufficient manner.展开更多
Bangladesh’s principal grain,rice,is essential to the nation’s agricultural economy and food security.In light of the obstacles and possibilities for increasing domestic output,this study looks at Bangladesh’s food...Bangladesh’s principal grain,rice,is essential to the nation’s agricultural economy and food security.In light of the obstacles and possibilities for increasing domestic output,this study looks at Bangladesh’s food productivity and degree of self-sufficiency in rice production.Even though the nation has made significant progress in rice production,problems including population growth,land degradation,climate change,and poor infrastructure still have an impact on total productivity.To examine the trajectory of Bangladesh’s agricultural sector from 1973 to 2023 through the following economic lenses:agricultural input use,GDP contribution,employment rate,trade trends,critical development indicators,and domestic rice demand and production.The data were chosen based on their accessibility,geographical context,relevance to the study’s aims,and time constraints.According to this study,rice production increased from 9.9 million tons in 1973 to 39.1 million tons in 2023,demonstrating the nation’s continuous efforts to increase agricultural output to satisfy rising market demand.展开更多
Capacity for grain self-sufficiency on the Tibetan Plateau(TP)is an important basis for ensuring social stability and regional sustainability.Thus,based on county-level statistical data for population,grain production...Capacity for grain self-sufficiency on the Tibetan Plateau(TP)is an important basis for ensuring social stability and regional sustainability.Thus,based on county-level statistical data for population,grain production and consumption,we analyzed patterns and trends in grain supply and demand at regional,provincial,and county levels on the TP between 1985 and 2016.We applied two indices to evaluate capacity for grain self-sufficiency and found that the regional average self-sufficiency rate increased quickly by 1.97%/a since 1989,reaching 173.03%on the plateau over the period between 2010 and 2016.This indicates that grain supply in this region is able to fully meet demand.In addition,all provinces apart from Xinjiang exhibited similar increasing trends,attaining grain self-sufficiency during 2010–2016.Furthermore,59%of counties attained grain self-sufficiency over this period,mainly distributed in southern Tibet,in the Sichuan-Tibet junction area,and in eastern Qinghai Province.A number of gaps in grain supply and demand occurred within the headwater regions of the Yangtze and Yellow rivers as well as on the Qiangtang Plateau.Grain self-sufficiency significantly increased over the study period in 36%of counties,mainly distributed in the agricultural areas of southeastern Tibet and in eastern Qinghai.Across the whole plateau,capacity for grain self-sufficiency substantially increased between 1985 and 2016,although serious spatial imbalances remain.展开更多
A building integrated photovoltaic (PV) and fuel cell (FC) system is proposed for assessment of the energy self-sufficiency rate in a city in Japan. The electricity consumed in the building is mainly supplied by solar...A building integrated photovoltaic (PV) and fuel cell (FC) system is proposed for assessment of the energy self-sufficiency rate in a city in Japan. The electricity consumed in the building is mainly supplied by solar panels, while the gap between the energy demand and supply is solved by the FC that is powered by the H2 produced by water electrolysis with surplus power of PV. A desktop case study of using the proposed system in Tsu city which is located in central part of Japan, has been conducted. The results found that the self-sufficiency rates of PV system to electricity demand of households (RPV) during the daytime in April and July are higher than those in January and October. The results also reveal that the self-sufficiency rate of FC system to the electricity demand (RFC) is 15% - 38% for the day when the mean amount of horizontal solar radiation is obtained in January, April, July and October. In addition, it is found the optimum tilt angle of solar panel installed on the roof of the buildings should be 0 degree, i.e., placed horizontally.展开更多
This paper seeks to explore the role of Remote Sensing in solving the agriculture related problems, which are the basic issues of sustainable development.
Renewable energy sources, including bioenergy, are presently attracting considerable attention as possible substitutes for fossil fuels. Among the various sources of bioenergy, biomass can arguably play a significant ...Renewable energy sources, including bioenergy, are presently attracting considerable attention as possible substitutes for fossil fuels. Among the various sources of bioenergy, biomass can arguably play a significant role in the reduction of greenhouse gases and the provision of a stable energy supply. However, the use of fossil fuels continues in the production of bioenergy. Consequently, the overall extent to which biomass utilization for energy can reduce carbon dioxide emissions as a substitute for fossil fuels and whether this can improve the energy self-sufficiency rate remains largely unknown. This study responds to these questions using a case of a Japanese rural community using firewood for residential heating. The results showed that woody biomass utilization for energy is able to both reduce the dependence on fossil fuels and mitigate climate change. These findings offer new insights into the development of sustainability in rural communities.展开更多
Most Japanese are enjoying rich and convenient dietary habits nowadays. However, majorities of Japanese are feeling anxiety about the future food supply because Japan＇s food self-sufficiency ratio has fallen most rap...Most Japanese are enjoying rich and convenient dietary habits nowadays. However, majorities of Japanese are feeling anxiety about the future food supply because Japan＇s food self-sufficiency ratio has fallen most rapidly in the last 45 years, and is lowest amongst countries with a population of more than 100 million. Major causes and mechanisms of the decline in the food self-sufficiency ratio over the last 45 years were analyzed. Drastic changes of dietary habits under rapid economic growth and sharp appreciation of the yen against the US dollar were found to be the major causes of the sharp decline of the food self-sufficiency ratio. Preliminary projections about the food self-sufficiency ratio in 2015 were carried out, and it was found that it will not be easy to achieve the policy goal of raising the food self-sufficiency ratio to 45% by 2015.展开更多
We investigate the weight-based food self-sufficiency ratio (WSSR) for Japan over a 50-year period (1961-2011) by applying factorial component analysis technique in order to measure the changes of the WSSR quantitativ...We investigate the weight-based food self-sufficiency ratio (WSSR) for Japan over a 50-year period (1961-2011) by applying factorial component analysis technique in order to measure the changes of the WSSR quantitatively. Quantitative data analysis is employed to determine the drivers of those changes. Numerical results show that Japan experienced a drastic decline in its food self-sufficiency ratio (FSSR) during the above period. The factorial component analysis shows that such a decline was caused by the changes in the FSSR of the food groups/items, not in the quantity of the food supply. A number of characteristics of those changes are presented and a list of major food groups that have major impacts on the changes is constructed. The findings in this paper reiterate the alarming food security problem in Japan and provide clear insight into the causes of this problem. The findings in this study pick up where previous studies have left off, aid the food-related policy-making process and identify new ideas for future food research.展开更多
Rice is the main food of Sierra Leoneans and an important source of employment and income for rural communities. According to the West African Rice Development Association report, annual consumption of rice is amongst...Rice is the main food of Sierra Leoneans and an important source of employment and income for rural communities. According to the West African Rice Development Association report, annual consumption of rice is amongst the highest in SubSaharan Africa（SSA）, 104 kg. Mainly, small scale farmers who are resource poor on both the upland and various lowlands grow rice. Sierra Leone has not been able to produce enough rice to meet its local consumption demand for a very long time now. 530 000 MT of milled rice is the required consumption need of the Sierra Leonean population per annum. In 2007, national paddy rice production was projected at 638 000 MT. The level of rice self-sufficiency rose from 50.57% in 2002 to 62.15% in 2006 and then to 63.49% in 2007. The remainder must be imported at increasingly expensive prices in the current situation of high food prices, which includes rice. The price of rice has seen a steady increase in the entire country. What most affected by this, is the low-income urban and peri-urban households. The promotion of domestic rice production is therefore a key element in the strategies for improving rice self-sufficiency, stimulating economic growth and increasing rural income. Therefore, supporting rice production programme is the only solution to pull the country out of the worsening rice situation and maintain the present trend in rice self-sufficiency. Therefore, having an understanding of the strategic interventions in rice production in Sierra Leone is an important ingredient in the promotion and attainment of rice self-sufficiency.展开更多
The stochastic production function estimates of rice and maize in Senegal River Valley demonstrate the possibility to reach self-sufficiency of rice in Senegal. Nonetheless, its fulfillment requires many accompanying ...The stochastic production function estimates of rice and maize in Senegal River Valley demonstrate the possibility to reach self-sufficiency of rice in Senegal. Nonetheless, its fulfillment requires many accompanying measures in rice and maize production. These measures include all upstream and downstream activities related to agricultural production for their efficiency and sustainability in rice and maize production to maintain the country＇s comparative advantages and competitiveness. Then priorities should be given to agricultural infrastructure building, establishment of credit markets, and providing an easy access of production factors （e.g., improved land, fertilizers, improved and certified seeds, as well as agricultural machines）. Furthermore, policy makers should provide a larger incentive in terms of producer price to encourage farmers to increase considerably their outputs, thereby farmers face smaller risk of having non-sold outputs. And during an early harvesting period, appropriate policy measures are in need to prevent farmers from dumping their products under severe social and economic pressures such as children schooling and loan payment, etc展开更多
In China’s countryside today, so far the foodstuffs for daily-life subsistence are still taken from the traditional farming production in addition to the yield of animal husbandry, while crop plantation takes the lio...In China’s countryside today, so far the foodstuffs for daily-life subsistence are still taken from the traditional farming production in addition to the yield of animal husbandry, while crop plantation takes the lion’s share in our rural economy. During the Medieval Age of the Western countries, however, special stress was placed on raising livestock on pastureland until the Industrial Revolution occurred in the 18th century when grain-oriented agriculture came into being. As a result of the unprecedented boom of modern science and technology now sweeping the whole world, farming productivity has sky-展开更多
Autarchy,so often evoked in contexts of energy and geopolitical crises,has always coincided with architecture itself,up to the great processes of de-territorialisation and the construction of the distribution network ...Autarchy,so often evoked in contexts of energy and geopolitical crises,has always coincided with architecture itself,up to the great processes of de-territorialisation and the construction of the distribution network in the Second Industrial Revolution.In this article,autarchy is investigated in its complex and remote roots,to be offered as a device for authentic ecological and social transformation.It is an antidote to a centralised,coercive and panoptic vision-the European Green Deal-which,by working with standards,ends up contradicting the very principles underlying ecology and the intrinsic value of heritage.Autarchy is in fact based on the principle of the singularity of the relationship between the subject and the territory and,precisely in this collusion,has constructed the specificity of places,in spite of the homogeneous and neutral space of the top-down vision of technological capitalism.The research is interested in making the home not the finished product of ecological capitalism,but the starting point,the activator of a new process of connivance between inhabitant and habitat in which the subject is called upon to realise himself as artifex,recovering skills that redeem him from the current diminutio of homo consumens.The status of homo faber is a way of defusing this process,an attempt to suspend the uniformity of capitalist technical thinking,now deeply absorbed as something natural.That suspension of the obvious is a form of self-sufficiency,of regaining singularity.展开更多
This article aims to analyze the repercussions of food trade between China and various regions of the world to understand the dynamics of food flows and offer a novel perspective on the contemporary globalization proc...This article aims to analyze the repercussions of food trade between China and various regions of the world to understand the dynamics of food flows and offer a novel perspective on the contemporary globalization process.Understanding these flows involves analyzing the global production and commercialization of food and the effects of these movements on exporting and importing countries in economic terms and food security.The concept of unequal caloric exchange is applied to the case of China,which allows for an understanding of how its economic growth and participation in international trade have transformed its global and internal commercial dynamics by establishing links with self-sufficiency and the composition of its population’s diet.The results show that China is increasingly dependent on international markets for its food supply.From 1961 to 2021,food consumption in China has tripled in calories and experienced qualitative changes,with a reduction in high-quality carbohydrates and vegetable proteins and an increase in cereals,vegetable oils,alcohol,and vegetables.This dietary transformation is related to economic growth and greater dependence on international trade.From 1987 to 2022,China has shown a growing deficit in the food trade balance,with imports exceeding exports in volume,value,and calories,although it maintains favorable terms of trade.Food self-sufficiency has decreased from 95%in 1961 to 76%in 2022,and the diet has diversified,replacing traditional foods with products demanded in international trade.展开更多
Generation of power through renewable energy resources is variable in nature due to their intermittence and the generation cost from these resources is also high for developing countries.Supportive policies and scheme...Generation of power through renewable energy resources is variable in nature due to their intermittence and the generation cost from these resources is also high for developing countries.Supportive policies and schemes like feed-in tariff and net metering are not so much attractive for consumers due to their insufficient rates and unfavorable institutional design.The shortcomings in these schemes can be avoided through self-consumption technique for roof top solar photovoltaic system,as this technique results in cheaper generation of electricity as compared to that of utility or grid.Therefore,prosumers are more attractive to use most of electrical power at cheapest price.In this paper,the cost and feasibility for the on-grid industrial solar photovoltaic system was analyzed.It is found from the results that store on-grid based photovoltaic system will be 0.0086$/(kW∙h)and utility will sell energy to the prosumers at rate of 0.062$/(kW·h),which will result in 35.23%reduction in annual cost of energy as compared to time of use rating model.Furthermore,96%of annual energy demand can be achieved by the proposed scheme,which guarantees the security of supply and the proposed model can be adopted for developing countries.展开更多
The impact of rapid urbanization on food security of China has received considerable attention.It is not clear whether China can strike a balance between urbanization and food security,especially grain security.There ...The impact of rapid urbanization on food security of China has received considerable attention.It is not clear whether China can strike a balance between urbanization and food security,especially grain security.There have been numerous studies examining the effects of urbanization on grain production or consumption,but few studies have yet analyzed grain balances.Based on the Chinese World Agricultural Regional Market Equilibrium Model（CWARMEM）,this paper explores the impacts of urbanization on national and regional grain balances through different scenarios.The CWARMEM is a global partial equilibrium multimarket model which captures the differences between urban and rural residents as well as the effects of globalization.The results show that urbanization has a small negative effect on maintaining grain self-sufficiency.Despite of that,China is able to achieve the objective of grain security set by its policymakers.Moreover,urbanization changes regional grain balances across China：The position of Northeast China and North China,as two dominant grain suppliers of China,will be weaken;Central China and East China will increase dependence on other grain suppliers;the grain surplus of Northwest China will increase slightly.Besides,in terms of grain category,urbanization helps China achieve self-sufficiency in food grain（rice and wheat）,while expands deficit of feed grain（maize）.展开更多
Based on an internationally recognized concept of food security, this paper has created a system of eight indicators to analyze China＇s food security. For the proper control and analysis of this study, the authors of...Based on an internationally recognized concept of food security, this paper has created a system of eight indicators to analyze China＇s food security. For the proper control and analysis of this study, the authors of this paper have chosen these indicators： supply, distribution, consumption, utilization efficiency, food security results, stability, sustainability and controllability. Results indicate that China＇s food security is currently at a high level and has been increasing in recent years. China＇s food security has multiple advantages with various indicators that include a self-sufficiency ratio, per capita calorie intake and protein supply that are above world average levels, even exceeding the average level of some developed countries. Major challenges facing China＇s food security include an unreasonable nutrition structure and poor environmental sustainability. In order to increase China＇s food security level, efforts must be made to adjust output structure, adopt an environmentally friendly pattern of production, attach importance to demand management, reduce unreasonable consumption and loss and moderately lower China＇s food reserve ratio.展开更多
A new type of plasma rocket engine,the Kabila rocket,using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is intro-duced and it achieves specific impulses...A new type of plasma rocket engine,the Kabila rocket,using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is intro-duced and it achieves specific impulses similar to the ones of conventional solid and bipropellant rockets.Curium-244 is chosen as a radioisotope heat source and a thermal reductive layer is also used to obtain precise thermionic emissions.The self-sufficiency principle is applied by simultane-ously heating up the emitting material with the radioisotope decay heat and by powering the differ-ent valves of the plasma rocket engine with the same radioisotope decay heat using a radioisotope thermoelectric generator.This rocket engine is then benchmarked against a 1 N hydrazine thruster configuration operated on one of the Pleiades-HR-1 constellation spacecraft.A maximal specific impulse and power saving of respectively 529 s and 32%are achieved with helium as propellant.Its advantages are its power saving capability,high specific impulses and simultaneous ease of storage and restart.It can however be extremely voluminous and potentially hazardous.The Kabila rocket is found to bring great benefits to the existing spacecraft and further research should optimize its geometric characteristics and investigate the physical principals of its operation.展开更多
基金Financial supports from Novo Nordisk Foundation(NNF16OC0021740)Aarhus Universitets Forskningsfond AUFFNOVA(AUFF-E-2015-FLS-9-12)Danmarks Frie Forskningsfond(DFF Technology and Production,0136-00206B)are greatly acknowledged.
文摘Cytochrome P450s(CYPs)are ubiquitously found in all kingdoms of life,playing important role in various biosynthetic pathways as well as degradative pathways;accordingly find applications in a vast variety of areas from organic synthesis and drug metabolite production to modification of biomaterials and bioremediation.Significantly,CYPs catalyze chemically challenging CAH and CAC activation reactions using a reactive high-valent iron-oxo intermediate generated upon dioxygen activation at their heme center,while the other oxygen atom is reduced to the level of water by electrons provided through a reductase partner protein.Self-sufficient CYPs,encoding their heme domain and reductase protein in a single polypeptide,facilitate increased catalytic efficiency and render a less complicated system to work with.The self-sufficient CYP enzyme from CYP102A family(CYP102A1,BM3)is among the earliest and most-investigated model enzymes for mechanistic and structural studies as well as for biotechnological applications.An increasing number of self-sufficient CYPs from the same CYP102 family and from other families have also been reported in last decade.In this review,we introduce chemistry and biology of CYPs,followed by an overview of the characteristics of self-sufficient CYPs and representative reactions.Enzyme engineering efforts leading to novel self-sufficient CYP variants that can catalyze synthetically useful natural and non-natural(nature-mimicking)reactions are highlighted.Lastly,the strategy and efforts that aim to circumvent the challenges for improved thermostability,regio-and enantioselectivity,and total turnover number;associated with practical use of self-sufficient CYPs are reviewed.
文摘One of the bottle-neck problems to the commercial development of supercritlcal water oxidation （SCWO） is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is analyzed. The reaction heat is recovered by means of Organic Rankine Circle. The process of SCWO for phenol is simulated with the Aspen Plus~ process simulator, and the results show that the influence of temperature on reaction heat is small at a constant pressure. It is reasonable to neglect the effect of temperature and to estimate the heat of reaction with average temperature when the temperature changes in a small range. The necessary condition to realize an energetically self-sufficient SCWO process is that the released energy is not less than consumed one. Whether a waste system with given chemical composition is energeticallyself-sufficient can be estimated by ^QR^QH 〉 W The thermodynamics analysis shows that energetically self-sufficient SCWO process with an Organic Rankine Cycle is a feasible technology for the recovery of SCWO reaction heat,and the energy balance point for phenol is 2wt%.
基金Project supported by the Key Program of the Higher Education Institutions of Henan Province(No.23A520009)。
文摘In recent research on image encryption,many schemes associate the key generation mechanism with the plaintext to resist chosen plaintext attacks.However,when the sender encrypts many images,a large amount of additional data related to the plaintext need to be transmitted,which leads to problems such as high transmission costs,high requirements for key storage space,and complex key management.Therefore,in this paper,we propose a self-sufficient plaintext-related JPEG image encryption scheme based on a unified key(SPJEU).This scheme establishes the connection between the plaintext and the key by selecting the direct current(DC)coefficients in the JPEG image through a unified key.Homomorphic encryption is applied to the selected DC coefficients,allowing plaintext information to be decrypted directly from the ciphertext domain using a specific calculation method.The remaining DC coefficients are encrypted through group diffusion,and the alternating current(AC)coefficients are grouped and permuted based on the run length.Extensive experiments show that our scheme can resist chosen plaintext attacks,avoid transmitting plaintext-related additional data in the communication channel,and simplify key management.This scheme also ensures the security and format compatibility of the ciphertext image,and the file increment after encryption is very small.
基金the National Natural Science Foundation of China(Project No.31900064)as well as the Natural Science Foundation of Heilongjiang Province of China(Project No.LH2019C012)。
文摘L-phenylglycine(L-phg)is a valuable non-proteinogenic amino acid used as a precursor to β-lactam antibiotics,antitumor agent taxol and many other pharmaceuticals.L-phg synthesis through microbial bioconversion allows for high enantioselectivity and sustainable production,which will be of great commercial and environmental value compared with organic synthesis methods.In this work,an L-phg synthesis pathway was built in Escher-ichia coli resulting in 0.23 mM L-phg production from 10 mM L-phenylalanine.Then,new hydroxymandelate synthases and hydroxymandelate oxidases were applied in the L-phg synthesis leading to a 5-fold increase in L-phg production.To address 2-oxoglutarate,NH_(4)^(+),and NADH shortage,a cofactor self-sufficient system was introduced,which converted by-product L-glutamate and NAD^(+)to these three cofactors simultaneously.In this way,L-phg increased 2.5-fold to 2.82 mM.Additionally,in order to reduce the loss of these three cofactors,a protein scaffold between synthesis pathway and cofactor regeneration modular was built,which further improved the L-phg production to 3.72 mM with a yield of 0.34 g/g L-phe.This work illustrated a strategy applying for whole-cell biocatalyst converting amino acid to its value-added chiral amine in a cofactor self-sufficient manner.
文摘Bangladesh’s principal grain,rice,is essential to the nation’s agricultural economy and food security.In light of the obstacles and possibilities for increasing domestic output,this study looks at Bangladesh’s food productivity and degree of self-sufficiency in rice production.Even though the nation has made significant progress in rice production,problems including population growth,land degradation,climate change,and poor infrastructure still have an impact on total productivity.To examine the trajectory of Bangladesh’s agricultural sector from 1973 to 2023 through the following economic lenses:agricultural input use,GDP contribution,employment rate,trade trends,critical development indicators,and domestic rice demand and production.The data were chosen based on their accessibility,geographical context,relevance to the study’s aims,and time constraints.According to this study,rice production increased from 9.9 million tons in 1973 to 39.1 million tons in 2023,demonstrating the nation’s continuous efforts to increase agricultural output to satisfy rising market demand.
基金Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA20040301National Natural Science Foundation of China,No.41771111+3 种基金The Youth Innovation Promotion Association,Chinese Academy of Sciences,No.2018071Fund for Excellent Young Talents in Institute of Geographic Sciences and Natural Resources Research,CAS,No.2016RC201Hebei Natural Science Foundation,No.D2019205123Research Fund of Hebei Normal University,No.L052018Z09。
文摘Capacity for grain self-sufficiency on the Tibetan Plateau(TP)is an important basis for ensuring social stability and regional sustainability.Thus,based on county-level statistical data for population,grain production and consumption,we analyzed patterns and trends in grain supply and demand at regional,provincial,and county levels on the TP between 1985 and 2016.We applied two indices to evaluate capacity for grain self-sufficiency and found that the regional average self-sufficiency rate increased quickly by 1.97%/a since 1989,reaching 173.03%on the plateau over the period between 2010 and 2016.This indicates that grain supply in this region is able to fully meet demand.In addition,all provinces apart from Xinjiang exhibited similar increasing trends,attaining grain self-sufficiency during 2010–2016.Furthermore,59%of counties attained grain self-sufficiency over this period,mainly distributed in southern Tibet,in the Sichuan-Tibet junction area,and in eastern Qinghai Province.A number of gaps in grain supply and demand occurred within the headwater regions of the Yangtze and Yellow rivers as well as on the Qiangtang Plateau.Grain self-sufficiency significantly increased over the study period in 36%of counties,mainly distributed in the agricultural areas of southeastern Tibet and in eastern Qinghai.Across the whole plateau,capacity for grain self-sufficiency substantially increased between 1985 and 2016,although serious spatial imbalances remain.
文摘A building integrated photovoltaic (PV) and fuel cell (FC) system is proposed for assessment of the energy self-sufficiency rate in a city in Japan. The electricity consumed in the building is mainly supplied by solar panels, while the gap between the energy demand and supply is solved by the FC that is powered by the H2 produced by water electrolysis with surplus power of PV. A desktop case study of using the proposed system in Tsu city which is located in central part of Japan, has been conducted. The results found that the self-sufficiency rates of PV system to electricity demand of households (RPV) during the daytime in April and July are higher than those in January and October. The results also reveal that the self-sufficiency rate of FC system to the electricity demand (RFC) is 15% - 38% for the day when the mean amount of horizontal solar radiation is obtained in January, April, July and October. In addition, it is found the optimum tilt angle of solar panel installed on the roof of the buildings should be 0 degree, i.e., placed horizontally.
文摘This paper seeks to explore the role of Remote Sensing in solving the agriculture related problems, which are the basic issues of sustainable development.
文摘Renewable energy sources, including bioenergy, are presently attracting considerable attention as possible substitutes for fossil fuels. Among the various sources of bioenergy, biomass can arguably play a significant role in the reduction of greenhouse gases and the provision of a stable energy supply. However, the use of fossil fuels continues in the production of bioenergy. Consequently, the overall extent to which biomass utilization for energy can reduce carbon dioxide emissions as a substitute for fossil fuels and whether this can improve the energy self-sufficiency rate remains largely unknown. This study responds to these questions using a case of a Japanese rural community using firewood for residential heating. The results showed that woody biomass utilization for energy is able to both reduce the dependence on fossil fuels and mitigate climate change. These findings offer new insights into the development of sustainability in rural communities.
文摘Most Japanese are enjoying rich and convenient dietary habits nowadays. However, majorities of Japanese are feeling anxiety about the future food supply because Japan＇s food self-sufficiency ratio has fallen most rapidly in the last 45 years, and is lowest amongst countries with a population of more than 100 million. Major causes and mechanisms of the decline in the food self-sufficiency ratio over the last 45 years were analyzed. Drastic changes of dietary habits under rapid economic growth and sharp appreciation of the yen against the US dollar were found to be the major causes of the sharp decline of the food self-sufficiency ratio. Preliminary projections about the food self-sufficiency ratio in 2015 were carried out, and it was found that it will not be easy to achieve the policy goal of raising the food self-sufficiency ratio to 45% by 2015.
文摘We investigate the weight-based food self-sufficiency ratio (WSSR) for Japan over a 50-year period (1961-2011) by applying factorial component analysis technique in order to measure the changes of the WSSR quantitatively. Quantitative data analysis is employed to determine the drivers of those changes. Numerical results show that Japan experienced a drastic decline in its food self-sufficiency ratio (FSSR) during the above period. The factorial component analysis shows that such a decline was caused by the changes in the FSSR of the food groups/items, not in the quantity of the food supply. A number of characteristics of those changes are presented and a list of major food groups that have major impacts on the changes is constructed. The findings in this paper reiterate the alarming food security problem in Japan and provide clear insight into the causes of this problem. The findings in this study pick up where previous studies have left off, aid the food-related policy-making process and identify new ideas for future food research.
文摘Rice is the main food of Sierra Leoneans and an important source of employment and income for rural communities. According to the West African Rice Development Association report, annual consumption of rice is amongst the highest in SubSaharan Africa（SSA）, 104 kg. Mainly, small scale farmers who are resource poor on both the upland and various lowlands grow rice. Sierra Leone has not been able to produce enough rice to meet its local consumption demand for a very long time now. 530 000 MT of milled rice is the required consumption need of the Sierra Leonean population per annum. In 2007, national paddy rice production was projected at 638 000 MT. The level of rice self-sufficiency rose from 50.57% in 2002 to 62.15% in 2006 and then to 63.49% in 2007. The remainder must be imported at increasingly expensive prices in the current situation of high food prices, which includes rice. The price of rice has seen a steady increase in the entire country. What most affected by this, is the low-income urban and peri-urban households. The promotion of domestic rice production is therefore a key element in the strategies for improving rice self-sufficiency, stimulating economic growth and increasing rural income. Therefore, supporting rice production programme is the only solution to pull the country out of the worsening rice situation and maintain the present trend in rice self-sufficiency. Therefore, having an understanding of the strategic interventions in rice production in Sierra Leone is an important ingredient in the promotion and attainment of rice self-sufficiency.
文摘The stochastic production function estimates of rice and maize in Senegal River Valley demonstrate the possibility to reach self-sufficiency of rice in Senegal. Nonetheless, its fulfillment requires many accompanying measures in rice and maize production. These measures include all upstream and downstream activities related to agricultural production for their efficiency and sustainability in rice and maize production to maintain the country＇s comparative advantages and competitiveness. Then priorities should be given to agricultural infrastructure building, establishment of credit markets, and providing an easy access of production factors （e.g., improved land, fertilizers, improved and certified seeds, as well as agricultural machines）. Furthermore, policy makers should provide a larger incentive in terms of producer price to encourage farmers to increase considerably their outputs, thereby farmers face smaller risk of having non-sold outputs. And during an early harvesting period, appropriate policy measures are in need to prevent farmers from dumping their products under severe social and economic pressures such as children schooling and loan payment, etc
文摘In China’s countryside today, so far the foodstuffs for daily-life subsistence are still taken from the traditional farming production in addition to the yield of animal husbandry, while crop plantation takes the lion’s share in our rural economy. During the Medieval Age of the Western countries, however, special stress was placed on raising livestock on pastureland until the Industrial Revolution occurred in the 18th century when grain-oriented agriculture came into being. As a result of the unprecedented boom of modern science and technology now sweeping the whole world, farming productivity has sky-
基金The research is part of the project‘Energy,water and food self-sufficiency in single-family housing in the North East’conducted at the IUAV University and funded by the PNRR-National Recovery and Resilience Plan,Mission 4,Component 2,Investment 1.5,INEST Ecosystem-Interconnected North-East Innovation,Spoke 4.Scientific directors of the research:Susanna Pisciella,Gabriele Torelli,Elena Giacomello,Francesco Trovò.
文摘Autarchy,so often evoked in contexts of energy and geopolitical crises,has always coincided with architecture itself,up to the great processes of de-territorialisation and the construction of the distribution network in the Second Industrial Revolution.In this article,autarchy is investigated in its complex and remote roots,to be offered as a device for authentic ecological and social transformation.It is an antidote to a centralised,coercive and panoptic vision-the European Green Deal-which,by working with standards,ends up contradicting the very principles underlying ecology and the intrinsic value of heritage.Autarchy is in fact based on the principle of the singularity of the relationship between the subject and the territory and,precisely in this collusion,has constructed the specificity of places,in spite of the homogeneous and neutral space of the top-down vision of technological capitalism.The research is interested in making the home not the finished product of ecological capitalism,but the starting point,the activator of a new process of connivance between inhabitant and habitat in which the subject is called upon to realise himself as artifex,recovering skills that redeem him from the current diminutio of homo consumens.The status of homo faber is a way of defusing this process,an attempt to suspend the uniformity of capitalist technical thinking,now deeply absorbed as something natural.That suspension of the obvious is a form of self-sufficiency,of regaining singularity.
基金supported by the Government of Catalonia,and the ETOS project(TED2021-132032A-I00)supported by the Spanish Ministry of Science and Innovation.
文摘This article aims to analyze the repercussions of food trade between China and various regions of the world to understand the dynamics of food flows and offer a novel perspective on the contemporary globalization process.Understanding these flows involves analyzing the global production and commercialization of food and the effects of these movements on exporting and importing countries in economic terms and food security.The concept of unequal caloric exchange is applied to the case of China,which allows for an understanding of how its economic growth and participation in international trade have transformed its global and internal commercial dynamics by establishing links with self-sufficiency and the composition of its population’s diet.The results show that China is increasingly dependent on international markets for its food supply.From 1961 to 2021,food consumption in China has tripled in calories and experienced qualitative changes,with a reduction in high-quality carbohydrates and vegetable proteins and an increase in cereals,vegetable oils,alcohol,and vegetables.This dietary transformation is related to economic growth and greater dependence on international trade.From 1987 to 2022,China has shown a growing deficit in the food trade balance,with imports exceeding exports in volume,value,and calories,although it maintains favorable terms of trade.Food self-sufficiency has decreased from 95%in 1961 to 76%in 2022,and the diet has diversified,replacing traditional foods with products demanded in international trade.
文摘Generation of power through renewable energy resources is variable in nature due to their intermittence and the generation cost from these resources is also high for developing countries.Supportive policies and schemes like feed-in tariff and net metering are not so much attractive for consumers due to their insufficient rates and unfavorable institutional design.The shortcomings in these schemes can be avoided through self-consumption technique for roof top solar photovoltaic system,as this technique results in cheaper generation of electricity as compared to that of utility or grid.Therefore,prosumers are more attractive to use most of electrical power at cheapest price.In this paper,the cost and feasibility for the on-grid industrial solar photovoltaic system was analyzed.It is found from the results that store on-grid based photovoltaic system will be 0.0086$/(kW∙h)and utility will sell energy to the prosumers at rate of 0.062$/(kW·h),which will result in 35.23%reduction in annual cost of energy as compared to time of use rating model.Furthermore,96%of annual energy demand can be achieved by the proposed scheme,which guarantees the security of supply and the proposed model can be adopted for developing countries.
基金supported by the Zhejiang Provincial Natural Science Foundation of China (LZ13G030002)
文摘The impact of rapid urbanization on food security of China has received considerable attention.It is not clear whether China can strike a balance between urbanization and food security,especially grain security.There have been numerous studies examining the effects of urbanization on grain production or consumption,but few studies have yet analyzed grain balances.Based on the Chinese World Agricultural Regional Market Equilibrium Model（CWARMEM）,this paper explores the impacts of urbanization on national and regional grain balances through different scenarios.The CWARMEM is a global partial equilibrium multimarket model which captures the differences between urban and rural residents as well as the effects of globalization.The results show that urbanization has a small negative effect on maintaining grain self-sufficiency.Despite of that,China is able to achieve the objective of grain security set by its policymakers.Moreover,urbanization changes regional grain balances across China：The position of Northeast China and North China,as two dominant grain suppliers of China,will be weaken;Central China and East China will increase dependence on other grain suppliers;the grain surplus of Northwest China will increase slightly.Besides,in terms of grain category,urbanization helps China achieve self-sufficiency in food grain（rice and wheat）,while expands deficit of feed grain（maize）.
基金sponsored by the Chinese Academy of Social Sciences(CASS)Innovation Programme
文摘Based on an internationally recognized concept of food security, this paper has created a system of eight indicators to analyze China＇s food security. For the proper control and analysis of this study, the authors of this paper have chosen these indicators： supply, distribution, consumption, utilization efficiency, food security results, stability, sustainability and controllability. Results indicate that China＇s food security is currently at a high level and has been increasing in recent years. China＇s food security has multiple advantages with various indicators that include a self-sufficiency ratio, per capita calorie intake and protein supply that are above world average levels, even exceeding the average level of some developed countries. Major challenges facing China＇s food security include an unreasonable nutrition structure and poor environmental sustainability. In order to increase China＇s food security level, efforts must be made to adjust output structure, adopt an environmentally friendly pattern of production, attach importance to demand management, reduce unreasonable consumption and loss and moderately lower China＇s food reserve ratio.
基金supported by Beijing Colleges and Universities Youth Talent Project(YETP1129)
文摘A new type of plasma rocket engine,the Kabila rocket,using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is intro-duced and it achieves specific impulses similar to the ones of conventional solid and bipropellant rockets.Curium-244 is chosen as a radioisotope heat source and a thermal reductive layer is also used to obtain precise thermionic emissions.The self-sufficiency principle is applied by simultane-ously heating up the emitting material with the radioisotope decay heat and by powering the differ-ent valves of the plasma rocket engine with the same radioisotope decay heat using a radioisotope thermoelectric generator.This rocket engine is then benchmarked against a 1 N hydrazine thruster configuration operated on one of the Pleiades-HR-1 constellation spacecraft.A maximal specific impulse and power saving of respectively 529 s and 32%are achieved with helium as propellant.Its advantages are its power saving capability,high specific impulses and simultaneous ease of storage and restart.It can however be extremely voluminous and potentially hazardous.The Kabila rocket is found to bring great benefits to the existing spacecraft and further research should optimize its geometric characteristics and investigate the physical principals of its operation.
