The Impact of Privatization on Terminal Efficiency: A Case Study of Tema Port

Port and terminal efficiency are of utmost importance to the container shipping industry due to their significance in enhancing the competitive advantage of ports within a region. Consequently, there have always been notable variations of studies around it. This paper analyzes the impact of privatization on terminal efficiency using the Port of Tema as a Case Study. The main objective of this paper is to analyze the efficiency trends of the public and private terminals in the port over the years. To achieve this objective, DEA-CCR methodology was employed to calculate the annual technical efficiency trends of the private and public terminals using four input variables and three output variables. The main results of the paper indicated that the public and private terminals were efficient for multiple years. However, the efficiency scores over the years demonstrated inconsistency, exhibiting notable fluctuations. The findings of this study will aid policymakers across the region on policies relating to the efficiency and ownership structure of ports and terminals.

Carbon sequestration rate,nitrogen use efficiency and rice yield responses to long-term substitution of chemical fertilizer by organic manure in a rice–rice cropping system

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield,soil carbon storage,and nutrient use efficiency.However,how the long-term substitution of chemical fertilizer with organic manure affects rice yield,carbon sequestration rate(CSR),and nitrogen use efficiency(NUE)while ensuring environmental safety remains unclear.This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield,CSR,and NUE.It also determined the optimum substitution ratio in the acidic soil of southern China.The treatments were:(i)NPK0,unfertilized control;(ii)NPK1,100%chemical nitrogen,phosphorus,and potassium fertilizer;(iii)NPKM1,70%chemical NPK fertilizer and 30%organic manure;(iv)NPKM2,50%chemical NPK fertilizer and 50%organic manure;and(v)NPKM3,30%chemical NPK fertilizer and 70%organic manure.Milk vetch and pig manure were sources of manure for early and late rice seasons,respectively.The result showed that SOC content was higher in NPKM1,NPKM2,and NPKM3 treatments than in NPK0 and NPK1 treatments.The carbon sequestration rate increased by 140,160,and 280%under NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK1 treatment.Grain yield was 86.1,93.1,93.6,and 96.5%higher under NPK1,NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK0 treatment.The NUE in NPKM1,NPKM2,and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons.Redundancy analysis revealed close positive relationships of CSR with C input,total N,soil C:N ratio,catalase,and humic acids,whereas NUE was closely related to grain yield,grain N content,and phenol oxidase.Furthermore,CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.The technique for order of preference by similarity to ideal solution(TOPSIS)showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE.Therefore,substituting 70%of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China.

Irrigation Water Use Efficiency of Farmers and Its Determinants: Evidence from a Survey in Northwestern China

Irrigation water shortage is becoming an increasingly serious problem in agricultural production. In this case, it is very important for policy makers to take measures to improve irrigation water use efficiency, especially in the water-scarce areas. In this paper, the data envelopment analysis （DEA） techniques, based on the concept of input-specific technical efficiency were used to develop farm-level technical efficiency measures and sub-vector efficiencies for irrigation water use. The Tobit regression technique was then adopted to identify the factors that influence irrigation water efficiency differentials under the shortage of water resources. Based on a sample data of 432 wheat farmers in northwestern China, our experimental results of the DEA analysis showed the average technical efficiency of 0.6151. It suggested that wheat farmers could increase their production by as much as 38.49% by using inputs more efficiently. Further, the mean irrigation water efficiency of 0.3065, suggested that wheat farmers could produce the same quantity of wheat using the same quantity of inputs but with 69.35% less water. The results of the Tobit regression analysis showed that the farmer＇s age, income, education level, and the farm size tended to affect the degree of irrigation water efficiency positively, and the channel conditions and different irrigation methods made a significant impact on irrigation water use efficiency. Furthermore, the arrangements of exclusive water property rights and competitive water price mechanism have effectively encouraged the water saving behavior of farmers. These results are valuable for policy makers since it could help to guide policies towards high irrigation water use efficiency.

Nitrogen Use Efficiency as Affected by Phosphorus and Potassium in Long-Term Rice and Wheat Experiments

Improving nitrogen use efficiency （NUE） and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N agronomic efficiency （NAE） and N loss in long-term （16- or 24-yr） experiments carried out at three rice-wheat rotation sites （Chongqing, Suining and Wuchang） in subtropical China. Three treatments were examined： sole chemical N, N＋phosphorus （NP）, and NP＋potassium （NPK） fertilizations. Grain yields at three sites were significantly increased by 9.3-81.6% （rice） and 54.5-93.8% （wheat） under NP compared with N alone, 1.7-9.8% （rice） and 0-17.6% （wheat） with NPK compared with NP. Compared to NP, NUE significantly increased for wheat at Chongqing （9.3%） and Wuchang （11.8%）, but not at Suining, China. No changes in NUE were observed in rice between NP and NPK at all three sites. The rice-wheat rotation＇s NAE was 3.3 kg kg1 higher under NPK than under NP at Chongqing, while NAE was similar for NP and NPK at Suining and Wuchang. We estimated that an uptake increase of 1.0 kg N hal would increase 40 kg rice and 30 kg wheat ha-1. Nitrogen loss/input ratios were -60, -40 or -30% under N, NP or NPK at three sites, indicating significant decrease of N loss by P or PK additions. We attribute part of the increase in NUE soil N accumulation which significantly increased by 25-55 kg ha-1 yr1 under NPK at three sites, whereas by 35 kg ha-1 yr-1 under NP at Chongqing only. This paper illustrates that apply P and K to wheat, and reduce K application to rice is an effective nutrient management strategy for both the NUE improvement and N losses reduction in China.

Determination of Gamma point source efficiency based on a backpropagation neural network

Efficiency is an important factor in quantitative and qualitative analysis of radionuclides, and the gamma point source efficiency is related to the radial angle,detection distance, and gamma-ray energy. In this work, on the basis of a back-propagation(BP) neural network model,a method to determine the gamma point source efficiency is developed and validated. The efficiency of the point sources ^(137)Cs and ^(60)Co at discrete radial angles, detection distances, and gamma-ray energies is measured, and the BP neural network prediction model is constructed using MATLAB. The gamma point source efficiencies at different radial angles, detection distances, and gamma-ray energies are predicted quickly and accurately using this nonlinear prediction model. The results show that the maximum error between the predicted and experimental values is 3.732% at 661.661 keV, 11π/24, and 35 cm, and those under other conditions are less than 3%. The gamma point source efficiencies obtained using the BP neural network model are in good agreement with experimental data.

What determines irrigation efficiency when farmers face extreme weather events? A field survey of the major wheat producing regions in China

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.

Determining N supplied sources and N use efficiency for peanut under applications of four forms of N fertilizers labeled by isotope^15N

Rational application of different forms of nitrogen（N） fertilizer for peanut（Arachis hypogaea L.） requires tracking the N supplied sources which are commonly not available in the differences among the three sources：root nodule,soil and fertilizer.In this study,two kinds of peanut plants（nodulated variety（Huayu 22） and non-nodulated variety（NN-1）） were choosed and four kinds of N fertilizers：urea-N（CONH_2-N）,ammonium-N（NH_4~＋-N）,nitrate-N（NO_3^--N） and NH_4~＋ ＋NO_3^--N labeled by^（15）N isotope were applied in the field barrel experiment in Chengyang Experimental Station,Shandong Province,China,to determine the N supplied sources and N use efficiency over peanut growing stages.The results showed that intensities and amounts of N supply from the three sources were all higher at middle growing stages（pegging phase and podding phase）.The accumulated amounts of N supply from root nodule,soil and fertilizer over the growing stages were 8.3,5.3 and 3.8g m^（-2） in CONH_2-N treatment,which are all significantly higher than in the other three treatments.At seedling phase,soil supplied the most N for peanut growth,then root nodule controlled the N supply at pegging phase and podding phase,but soil mainly provided N again at the last stage（pod filling phase）.For the whole growing stages,root nodule supplied the most N（47.8 and 43.0%） in CONH_2-N and NH_4~＋-N treatments,whereas soil supplied the most N（41.7 and 40.9%） in NH_4~＋ ＋NO_3^--N and NO_3^--N treatments.The N use efficiency was higher at pegging phase and podding phase,while accumulated N use efficiency over the growing stages was higher in CONH_2-N treatment（42.2%） than in other three treatments（30.4%in NH_4~＋-N treatment,29.4%in NO_3^--N treatment,29.4%in NH_4~＋ ＋NO_3^--N treatment）.In peanut growing field,application of CONH_2-N is a better way to increase the supply of N from root nodule and improve the N use efficiency.

Monte-Carlo simulation to determine detector efficiency of plastic scintillating fiber

Fundamental characteristics of the plastic scintillating fiber (PSF) as a detector for electromagnetic radiation (X & γ) are obtained by GEANT4 detector simulation tool package. The detector response to radiation with energy of 10~400 keV is found out. Energy deposition as well as detector efficiency (DE) of the PSF are studied. In order to make linear array of the PSF for imaging purpose, the optimum length of fiber is also estimated.

The efficiency of long-term straw return to sequester organic carbon in Northeast China＇s cropland

Black soil is one of the most precious soil resources on earth because it has abundant carbon stocks and a relatively high production capacity. However, decreasing organic matter after land reclamation, and the effects of long-term inputs of organic carbon have made it less fertile black soil in Northeast China. Straw return could be an effective method for improving soil organic carbon（SOC） sequestration in black soils. The objective of this study was to evaluate whether straw return effectively increases SOC sequestration. Long-term field experiments were conducted at three sites in Northeast China with varying latitudes and SOC densities. Study plots were subjected to three treatments： no fertilization（CK）; inorganic fertilization（NPK）; and NPK plus straw return（NPKS）. The results showed that the SOC stocks resulting from NPKS treatment were 4.0 and 5.7% higher than those from NPK treatment at two sites, but straw return did not significantly affect the SOC stocks at the third site. Furthermore, at higher SOC densities, the NPKS treatment resulted in significantly higher soil carbon sequestration rates（CSR） than the NPK treatment. The equilibrium value of the CSR for the NPKS treatment equated to cultivation times of 17, 11, and 8 years at the different sites. Straw return did not significantly increase the SOC stocks in regions with low SOC densities, but did enhance the C pool in regions with high SOC densities. These results show that there is strong regional variation in the effects of straw return on the SOC stocks in black soil in Northeast China. Additional cultivations and fertilization practices should be used when straw return is considered as an approach for the long-term improvement of the soil organic carbon pool.

Determination of aerosol extinction coefficient and mass extinction efficiency by DOAS with a flashlight source

With the method of differential optical absorption spectroscopy （DOAS）, average concentrations of aerosol particles along light path were measured with a flashlight source in Chiba area during the period of one month. The optical thickness at 550 nm is compared with the concentration of ground-measured suspended particulate matter （SPM）. Good correlations are found between the DOAS and SPM data, leading to the determination of the aerosol mass extinction efficiency （MEE） to be possible in the lower troposphere. The average MEE value is about 7.6m^2.g^-1 , and the parameter exhibits a good correlation with the particle size as determined from the wavelength dependence of the DOAS signal intensity.

Increase in yield and nitrogen use efficiency of double rice with long-term application of controlled-release urea

Controlled-release urea(CRU)has better characteristics than conventional urea for synchronizing nitrogen(N)release with plant uptake.Understanding the effects of CRU on crop yield and N use efficiency(NUE)has long been the key to evaluate the performance of CRU.A long-term experiment over five consecutive years was conducted in Changsha,Hunan Province,China,to investigate the effects of polyethylene-coated urea with a 90-d release period on the yield and NUE of double rice(early and late crops are grown in the same year),the amount of residual soil mineral N and the soil–plant N balance,as well as on the economic benefits.Four N fertilizer treatments including CK(no N fertilizer),U(conventional urea),CRU1(polyethylene-coated urea with equal N application rate to U)and CRU2(20%reduction in N application rate of CRU1)were established.The results indicated that CRU1 application increased the yield and NUE of double rice by 11.0 and 13.5%,respectively,compared with U.Higher yield and NUE of late rice were found than in early rice in CRU treatments.Compared with conventional U,the yield and NUE of early rice in the CRU1 treatment were increased by 6.0 and 10.2%,respectively,and those of late rice were increased by 15.4 and 13.8%,respectively.There was no significant difference between CRU1 and CRU2 in double rice yield.Furthermore,CRU treatments(including CRU1 and CRU2)had higher apparent residual Nmin rate(ARNR)and apparent N recovery rate(ANRR),but lower apparent N loss(NS)than the conventional U treatment.Concentrations of NH_(4)^(+)-N and NO_(3)^(-)-N were greater in the surface soil(0–20 cm)and lower in the deeper soil layer(40–60 cm)with CRU treatments than in the U treatment after harvest.Moreover,CRU application produced a greater economic benefit than conventional U application.In general,CRU outperformed U fertilizer in terms of rice yield,NUE,soil–plant N balance,economic benefit,and CRU2 provided greater comprehensive benefits than CRU1.It is suggested that CRU application is beneficial for solving N management challenges in the production of rice.

Determining the Technical Efficiency of Specialty Ophthalmology Hospital Using SFA and DEA: 2009-2011

Introduction: During the last decade, the health sector of many countries in general has been faced significantly with the increase of health care costs and in particular with the growth in hospital costs, that a significant part of it is due to the inefficient use of resources. The present study has been calculated the technical efficiency of the Specialty Ophthalmology Hospital of Tehran University of Medical Sciences by the comprehensive data analysis methods and stochastic frontier analysis. Methods: In this article, the technical efficiency of the Specialty Ophthalmology Hospital of Tehran University of Medical Sciences has been calculated by the years of 2009 to 2011, by the comprehensive data analysis methods and stochastic frontier analysis. For this purpose, the form of input-oriented data envelopment analysis approach was used by assuming the variable Productivity to scale and stochastic frontier analysis method and from the five output, the occupied bed days, outpatient admissions, inpatient admissions, inpatient days and bed occupancy factor, and from the six output, it means active beds, number of doctors, nurses, and other personnel, budget and equipment costs were used for the study. For data analyzing, Deap software, edit 1/2 and Frontier edit 1/4, was used. Result: The results of a comprehensive data analysis method showed: 1) The capacity of improving technical efficiency in the studied sector is 34% (average technical efficiency is 0.663 parts);and 2) some of the sectors are met the excess inputs (factors of production). Technical efficiency using stochastic frontier analysis was equal to 0.937. In fact, the stochastic frontier analysis showed the inefficiency is less than the actual value. Conclusion: Reducing excess capacity factors (factors of production) should be conducted in the form of a comprehensive plan and by considering all regarded aspects, that this reduction plays a major role in the hospital and health sector costs reduction.

Prediction of face advance rate and determination of the operation efficiency in retreat longwall mining panel using rock engineering system

A new approach for prediction of face advance rete (FAR) prior to mining operation and determination of the operation efficiency after mining operation in retreat longwall mining panel is presented based upon the concepts of rock engineering system (RES). For this purpose, six longwall panels considered in Parvadeh-I coal mine. Seven major effective parameters on FAR was selected including coal mine roof rating, gas propagation, safety factor of longwall face, ratio of joint spacing to cutting depth at longwall face, longwall face inclination, panel width, floor rock mass rating. To performance evaluation of the presented model, the relationship between the average vulnerability indexes of advance operation with FAR was determined in considered panels with coefficient of determination (R2) equal to 0.884 that indicate relatively acceptable correlation and compatibility. Investigations of the research indicated that it is possible to determine the actual operation efficiency under fair conditions by a RES-based model. The inevitable reduction of FAR for each longwall panel was determined by presented model that the difference amount between the maximum possible practical face advance rate (FARmpp) and recorded actual face advance rate (FARa) indicate the operation efficiency. Applied approach in this paper can be used to prediction of FAR in retreat longwall mining panel for same conditions that can have many benefits, including better and more accurate planning for the sales market and mine operation. Also, presented method in this paper can be applied as a useful tool to determination of actual operation efficiency for other sections and extraction methods in coal mines.

Determination of optimal grid opening width for herringbone water-sediment separation structures based on sediment separation efficiency

The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and determining the grid opening width D, a crucial structure parameter for HWSSS design. Theoretical analysis on the total sediment separation rate Pt reveals that the efficiency of sediment separation is much related with sediment grain size distribution(GSD) and grid opening width. The lower limit of Pt is deduced from the perspective of safety consideration by transforming debris flow into sediment-laden flow. Hydraulic model tests were carried out. Based on the regression analysis of the experimental data, the quantitative relationships between Pt and D and GSD characteristic values were finally established. A procedure for determining optimal grid opening width is proposed based on these analyses. These results are of significance in evaluating sediment separation effect by HWSSS in debris flow prevention and contribute to a more explicit methodology for design of HWSSS.

Determination of Irrigation Supply Efficiency in Challenging Environment Case Study of Bal’ad District, Middle Shabelle Region in Somalia

The paper aims to determine the irrigation water supply efficiency of different irrigation methods used in the challenging environment of Bal’ad district in Somalia. Data was collected from the literature, field visits using field records and scheduled interviews, GPS coordinates and from ancillary information, such as remote sensing images and existing national maps. A comparison was done by use of secondary sources, such as academic journals using information from authorities on irrigation and water loss. Sampling was done by use of Snow balling. The results highlighted response rate for farmers being 80% while that of NGO employees is 75.76%. According to the results, the main ways through which irrigation water is lost is through: evaporation;seepage through the canal bunds;overtopping the bunds;overflow losses and overwatering with the average field application efficiency of 25% and conveyance efficiency of 30%. These generated a scheme irrigation efficiency of 7.5% which is poor for surface irrigation prevalent in the study area. The loss of irrigation water was found to be reduced by the following: daily supervision;proper maintenance;water allocation to farmers;good management;lining of canals;management of irrigation methods;ongoing evaluation;good land preparation;and training farmers.

Study on Intermittent Irrigation for Paddy Rice: I. Water Use Efficiency

A field experiment was conducted in a well-puddled paddy field developed on the Tama River alluvial soil in the Farm of Tokyo University of Agriculture and Technology, Japan, to study the effect of intermittent irrigation on water use efficiency of paddy rice. Four treatments were arranged with 2 replicates: continuous flooding irrigation treatments (CFI), and three intermittent irrigation treatments Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Water consumption was lower in treatment Ⅱ-0 than in treatment CFI because the percolation rate was reduced by the reduction in the hydraulic head of ponded water. Intermittent irrigation led to soil repeated shrinking and swelling in Ⅱ-1 and Ⅱ-2 plots and, therefore, soil cracks developed rapidly. Since they became the major routes of water percolation, the soil cracks increased water consumption in treatments Ⅱ-1 and Ⅱ-2. There were no significant differences in dry matter production and grain yields between treatment Ⅱ-0 and treatment CFI, but the dry matter production and grain yields in treatments Ⅱ-0 and CFI were significantly higher than those in treatments Ⅱ-1 and Ⅱ-2. Therefore, the water use efficiency in the treatments was in the order of Ⅱ-0 > CFI > Ⅱ- 2 > Ⅱ- 1.

Gadolinium-incorporated CsPbI_(2)Br for boosting efficiency and long-term stability of all-inorganic perovskite solar cells

All-inorganic CsPbI_(2)Br perovskite solar cells(PSCs)have received extensive research interests recently.Nevertheless,their low efficiency and poor long-term stability are still obstacles for further commercial application.Herein,we demonstrate that high efficiency and exceptional long-term stability are realized by incorporating gadolinium(III)chloride(GdCl_(3))into the CsPbI_(2)Br perovskite film.The incorporation of GdCl_(3) enhances the Goldschmidt tolerance factor of CsPbI_(2)Br perovskite,yielding a dense perovskite film with small grains,thus the a-phase CsPbI_(2)Br is remarkably stabilized.Additionally,it is found that the GdCl_(3)-incorporated perovskite film achieves suppressed charge recombination and appropriate energy level alignment compared with the pristine CsPbI_(2)Br film.The noticeable increment in efficiency from14.01%(control PSC)to 16.24%is achieved for GdCl_(3)-incorporated PSC.Moreover,the nonencapsulated GdCl_(3)-incorporated PSC exhibits excellent environmental and thermal stability,remaining over 91%or90%of the original efficiency after 1200 h aging at 40%relative humidity or 480 h heating at 85℃ in nitrogen glove box respectively.The encapsulated GdCl_(3)-incorporated PSC presents an improved operational stability with over 88%of initial efficiency under maximum power point(MPP)tracking at 45℃ for1000 h.This work presents an effective ion-incorporation approach for boosting efficiency and long-term stability of all-inorganic PSCs.

Technical efficiency and its determinants of the various cropping systems in the purple-soiled,hilly region of southwestern China

This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.

Developing a Transformation-Independent and Unbiased qPCR Assay to Rapidly Evaluate the Determinants of DNA Assembly Efficiency

Synthetic biology is moving in the direction of larger and more sophisticated design,which depends heavily on the efficient assembly of genetic modules.Conventional evaluation of the DNA assembly efficiency(AE)requires transformation,and the whole process requires up to 10 h and is susceptible to various interferences.To achieve rapid and reliable determination of the AE,an alternative transformation-independent method was established using a modified quantitative polymerase chain reaction(qPCR)assay.The AE is represented by the proportion of the ligated fragment,which can be determined within 3 h.This qPCR-based measurement was tested by the commonly used restriction ligation,Golden Gate assembly,and Gibson assembly for the assembly of two or more DNA pieces;the results correlated significantly with the AEs represented by the counting of the colony-forming units(CFUs).This method outperformed the CFU-based measurement by reducing the measuring bias and the random deviations that stem from the transformation process.The method was then employed to investigate the effects of terminal secondary structures on DNA assembly.The results revealed the major effects of the overall properties of the overlap sequence and the negative effects of hairpin structures on the AE,which are relevant for all assembly techniques that rely on homologous annealing of the terminal sequences.The qPCR-based approach presented here should facilitate the development of DNA assembly techniques and the diagnosis of inefficient assemblies.

In situ determination on food consumption and ecological conversion efficiency of a marine fish species, Hyporhamphus sajori

The food consumption and ecological conversion efficiency of a species marine pelagic andsmall size fish, Hyporhamphus sajori, were determined by using in situ stomach content method presented by Eggers. The results showed that: (1) the fish was taken in food all day, so empty-stomach rate was very low, taking up about 4.5% of the total determined fish number. However, the fish still has significant daily feeding rhythm. A feeding peak was found 0:00 o'clock at night, but feeding level was always high in the daytime; (2) relationship between instantaneous food content in stomach and corresponding time could be described as S_t = a · e (-b·t). There was not significant difference of instantaneous gastric evacuation rate between two determinations, with average value being 0.13 × 10^(-2) g/ (g' h) (wet weight); (3) the daily food consumption tended to change in irregular waving form, with average value being (10.16Xl0^(-2)±1.19xl0(-2) g/ (g·d) (wet weight) or (55.56 × 10(-2) ±6.51 × 10^(-2) kJ/ (g·d). The wave distance is constant and about 14 d, but the wave height changed largely; (4) actual determining value of daily growth rate was 3.24 × 10^(-2)g/ (g·d) (wet weight) or 12.91 × 10^(-2)kJ/ (g·d), from which 31.89% (wet weight) or 23.24% kJ of ecological conversion efficiency could be obtained.