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The economics surrounding five algae-to-fuels process scenarios were examined. The different processes modeled were as follows: an open pond producing either triacylglycerides (TAG) or free fatty acid methyl ester (FAME), a solar-lit photobioreactor producing either FAME or free fatty acids (FFA), and a light emitting diode irradiated (LED-lighted) photobioreactor producing TAG. These processes were chosen to represent both classical and esoteric approaches presented in the open literature. Viable (or suggested) processing techniques to liberate and purify (and convert) the microalgal triacylglycerides were then modeled to accompany each growth option. The investment and cost per kg of fuel or fuel precursor for each process was determined. The open pond produced TAG at ~$7.50/kg, while the process using the LED-lit photobioreactor produced TAG at ~$33/kg. The scenario containing the solar-lit photobioreactor produced FAME at ~$25/kg, while the open pond produced FAME at ~$4/kg. The scenario containing the solar-lit photobioreactor produced FFA at ~$29/kg. The open pond scenarios appear to be closest to the $1/kg pricepoint at this time, and thus are the most viable economic options. Future technological advancements that reduce the cost of bioreactor vessels, LED lighting, and solvent recovery, may reduce the oil production costs of these scenarios to a more attractive level.  相似文献   
3.
随着生物制药行业环境的变化和大剂量产品的出现,生产成本的压力日益凸现。从经济的角度探讨了重组药物上游及下游工艺设计和优化对投资和运转成本的影响,对于生物制药企业降低成本,提高竞争力有积极意义。  相似文献   
4.
目的 评价预防性应用微生态制剂(培菲康)防治婴幼儿肺炎继发腹泻的疗效及成本效益.方法 2008年1月到2010年9月住院治疗的婴幼儿肺炎966例为研究对象,对患儿的临床特征、微生态制剂(培菲康)预防性应用情况、是否出现继发腹泻及住院治疗费用的关系进行分析.结果 干预组594例,对照组372例,两组住院治疗期间继发腹泻的发病率分别为18.69%、39.78%,两组比较,x2 =51.889,P <0.01,RR=0.470;干预组99例发生继发腹泻后继续原有微生态制剂治疗,对照组134例因继发腹泻才开始应用同类微生态制剂治疗,两组腹泻治疗总有效率分别86.87%、74.63%,差异无统计学意义(x2=5.299,P=O.021).干预组、对照组每例(次)患儿住院总费用分别为(2775.0±1724.2)元和(3130.7±1899.8)元,预防性应用微生态制剂(培菲康)次均节省直接医疗费用支出355.6元,差异有统计学意义(t =2.998,P=0.003);预防性应用微生态制剂(培菲康)的效益成本比为13.02.结论 预防性应用微生态制剂(培菲康)不仅能降低肺炎继发腹泻的发病率,缩短住院病程,提高腹泻治疗总有效率,同时,明显降低患儿的次均医疗费用,效益成本比高.  相似文献   
5.
Economic consequences of reproductive performance in dairy cattle   总被引:1,自引:0,他引:1  
The net economic value of reproductive efficiency in dairy cattle was estimated using a stochastic dynamic simulation model. The objective was to compare the economic consequences of reproductive performance scenarios (“average” and “poor”) of a cow having a good reproductive performance and to explore which reproductive factors have an important impact on economic efficiency. A “good” reproductive performance scenario was defined with 1 ovulation rate (POVUi), 0.7 estrus detection rate (PEst), 0.7 conception rate (PCon), 0.03 incidence rate of postpartum disorders prolonging the ovarian cyclicity (CO), 0.2 incidence rate of postpartum disorders reducing conception (ME), 0.05 embryonic death rate (ED), and voluntary waiting period (VWP) of 9 wks pp (post partum). In the current situation of dairy cows in the Netherlands, an “average” reproductive scenario (0.95 POVUi, 0.5 PEst, 0.5 Pcon, 0.07 CO, 0.27 ME, 0.07 ED and VWP of 12 wks pp) and a “poor” reproductive scenario (0.90 POVUi, 0.3 PEst, 0.3 Pcon, 0.11 CO, 0.33 ME, 0.09 ED and VWP of 15 wks pp) were identified. A sensitivity analysis was performed by comparing changes of single effect of factors in a good and poor scenario with the average scenario. The mean net economic loss (NELi) compared with the good scenario was €34 and €231 per cow per year for the average and poor reproductive performance scenario, respectively. Increasing the calving interval resulted in greater economic loss. The important factors on the cost of reproductive efficiency were the involuntary culling cost and the return of milk production. Variation in PCon, PEst, ME, ED, and VWP had large impacts on economic benefits.  相似文献   
6.
Eco(nomics/logy)     
This note discusses the analytic tools available for studying the interrelations between the economy and the ecological system. It points out the importance of the concept of cooperative games as an addition to the emphasis on non-cooperative games in both economics and ecology. The relation between both concepts of the games and the market system is discussed.  相似文献   
7.
This paper discusses generally why humans should bother to conservesea turtles. In doing so, it considers both economic and non-economic reasonsand outlines threats to the existence of sea turtles and ways in which tourismmay either contribute to the conservation or decline of their populations.Turtle-based ecotourism at Mon Repos in southern Queensland is described. As aresult of a survey conducted by the authors, it is shown that turtle-basedecotourism at Mon Repos has positive social (indirect) consequences for theconservation of sea turtles. Furthermore, it is argued that ecotourismoperations at Mon Repos have positive direct impacts on the sustainability ofpopulations of sea turtles. However, using a simple model, it is emphasised thatthis impact is limited because turtles are migratory. A model is also developedto capture the possible relationship between turtle populations and thesustainability of ecotourism dependent on turtle populations, and is extended toother wildlife species. Significant interdependence exists between thesustainability of these two variables. The theory is related toCiriacy-Wantrup's social safe minimum conservation standard forspecies' survival.  相似文献   
8.
BackgroundFaculty vitality is the main ingredient to enhance professional education and competence. Enriching the faculty vitality in key domains of teaching, assessing, research, professionalism, and administration is perceived to improve educational environment significantly and enhances the academic performance of learners. Faculty development program (FDP) has been considered as a stand-alone educational pedagogy in fostering knowledge and professional skills of faculty. However, few studies have provided objective reports about the impact of such programs in a healthcare system.MethodsThis research was conducted by selecting data sources of PubMed-Medline, Wiley online library, Cochrane library, Taylor & Francis Online, CINAHL, Springer link, Proquest, ISI Web of knowledge, ScienceDirect, EJS, EBSCO, Blackwell, Emerald and ABI Inform. This search followed a step-wise approach defined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A total of 37 studies that explored the impact of FDPs on medical and allied health faculty’s professional development were selected.ResultsThis meta-analysis reported a mean effect size of 0.73 that reflects a significant and positive impact of FDPs in enhancing faculty’s knowledge and professional competence (z-statistics of 4.46 significant at p-value < 0.05) using the random effects model and forest plot.ConclusionThis article reiterates the incorporation of FDPs in all healthcare institutions for improving the academic performance of faculty with resultant enrichment of learners’ knowledge and skills.  相似文献   
9.
The Nobel laureate Angus Deaton concentrated his work on puzzling developments and phenomena in economics. Puzzles are exciting elements in economics, because readers feel challenged by the question of how they can be solved. Among the puzzles analyzed by Deaton are: (1) Mortality increase of white, U.S. non-Hispanic men (2000 to today); (2) Why are height and income sometimes closely correlated, but not always?; (3) Height inequality among males and females; and (4) The Indian puzzle of declining consumption of calories during overall expenditure growth.This article reviews these “puzzles” and the main insights that Deaton derived from their discussion insofar as they pertain to the biological aspects of human development. I will focus on the field of this journal, Economics and Human Biology, in which Deaton has been very active over the last two decades. I will also document some of the responses by other scholars and their contributions to these puzzles, as they relate to the field of economics and human biology.  相似文献   
10.
Plagues of rodents in field crops have been a problem of human societies for centuries. These problems diminished with the onset of effective herbicides and clean farming practices in the 1960s, but there has been a resurgence of rodent irruptions in cropfields since the advent of conservation tillage systems. We examined the efficacy of in-furrow applications of 2% zinc phosphide (Zn3P2) pellets (27.5 kg ha−1 [5 lb acre−1]) at planting for the control of rodent damage in no-till corn. Three independent field studies were conducted in northeastern NE, southern IL, and southern IN. Vole populations in the most severely damaged fields (IL) ranged from 104 to 138 active colonies ha−1. Zn3P2 reduced yield loss in the three study areas by 7–34%. Projected economic returns ranged from US$1044 to US$5360, based on representative 64-ha fields and a net profit of US$250 ha−1. Benefit:cost ratios ranged from 1.1 to 5.6:1 and were directly related to vole population levels. To prevent rodent damage in no-till cornfields, we recommend an integrated pest management approach that incorporates the use of a combination of the following techniques: rodent population monitoring, economic thresholds, mowing, early pre-plant herbicides, broadcast whole-kernel corn, and in-furrow applications of Zn3P2 pellets.  相似文献   
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