Management,operational, animal health,and economic characteristics of large dairy herds in 4 states in the Upper Midwest of the United States

Recent trends in dairy farm structure in the United States have included a decreasing number of farms, although farm size has increased, especially the share of milk production from very large herds (>2,500 cows). The objectives of this observational study were to describe common management practices; to characterize labor and operational structure; to measure some aspects of animal health, including lameness, hock lesions, mortality, and mastitis incidence; and to summarize cost of production on farms with more than 2,500 cows in 4 states in the Upper Midwest of the United States. The study included 15 dairy farms in Minnesota, Wisconsin, Iowa, and South Dakota. Farms were visited twice, once each year, and on-farm herd records were collected for those 2 yr. On-farm herd records were used to investigate mortality, culling, pregnancy rate, and clinical mastitis incidence. At least 1 high-producing pen of mature cows and 1 pen of fresh cows were scored for locomotion. Likewise, at least 1 pen of high-producing mature cows was scored for cleanliness and hock lesions. Median herd size was 3,975 cows (range = 2,606–13,266). Milk sold per employee was 1,120,745 kg and the number of cows per employee was 105. Eighty percent of the farms had Holstein cows, 13% had Jersey, and 7% had Jersey-Holstein crosses. All farms used artificial insemination as the sole form of breeding and 100% of the farms used hormonal synchronization or timed artificial insemination programs in their reproductive protocols; 21-d pregnancy rate was 21.7%. Median lameness prevalence was 18.3% and median severe lameness prevalence was 5.1%. Median hock lesion prevalence was 17.4% and median severe hock lesion prevalence was 1.9%; mortality rate was 7.4%. Clinical mastitis incidence was 62.5 cases per 100 cow-years. Feed costs accounted for approximately 53% of the total cost of producing milk, followed by labor at 11%, interest and depreciation expenses at 10%, and replacement costs at 9.5%. Herds in the top 50th percentile for profitability had a net income of $2.40 per hundredweight of milk sold compared with $0.95 per hundredweight for herds in the bottom 50th percentile. Although results of this study were helpful in understanding how large dairy systems operate in the Upper Midwest, more research is yet needed with a larger number of farms and wider variety of management practices to identify factors within these large farms that promote optimal animal health and profitability.     

Testing activity‐based costing to large‐scale combined heat and power plant using bioenergy

This paper deals with the energy production and economics of a large‐scale biomass‐based combined heat and power (CHP) plant. An activity‐based costing model was developed for estimating the production costs of the heat and power of the bio‐CHP. A 100 MW plant (58 MW heat, 29 MW electricity) was used as reference. The production process was divided into four stages: fuel handling, fluidized bed boiler, turbine plant, and flue gas cleaning. The boiler accounted for close to 50% of the production costs. The interest rates and the utilization rate of the CHP had a significant effect on the profitability. We found that below 4000–4500 h per year utilization, the electricity production turned unprofitable. However, the heat production remained profitable with high interest rate (10%) and a low utilization rate (4000 h). The profitability also depended on the type of biomass used. We found that, e.g. with moderate interest rates and high utilization rate of the plant, the bio‐CHP plant could afford wood and Reed canary grass as fuel sources. Copyright © 2013 John Wiley & Sons, Ltd.     

Economical Evaluation of CO2-EOR Projects in the Middle East

Abstract

Recently, there is a growing interest the in oil industry to utilize carbon dioxide (CO₂) to enhance oil production from mature reservoirs. Conversely, there is a rising global attention to reduce CO₂ emissions from burning fossil fuels due to environmental concerns. Synchronization between these two objectives is promising through CO₂ Capture and Storage (CCS) projects where CO₂ is captured from large emission sources and then storedin safe geological structures. Economical evaluation of CO₂-EOR projects is a crucial measure in order to ensure a project's viability.

In this study, an efficient model was developed to predict the economics of CO₂-EOR projects. The developed model consists of five modules that are linked together to allow for fast prediction of CO₂-EOR economics.

The model was used to predict the economics of a case study where CO₂-EOR application is considered for a Middle Eastern reservoir. Moreover, the case study was subjected to sensitivity analyses to evaluate the effects of several parameters on the various economical components of CO₂-EOR projects.     

经管类专业校企互动实践教学模式的启示

实践环节教学工作是高校教学工作的重要组成部分,校企互动是高校教学改革的新路子。以我国普通高校为主体,研究经管类专业校企互动的模式与启示。校企双方互利互赢利益机制;建立具有一定权威的约束机制;校企诚信友谊机制;科学设计,制度先行,发挥实习教师纽带作用。     

Consumption behavior and the aspiration for conformity and consistency.

The (socio-)psychological concepts of individual aspiration for conformity and consistency are integrated into the rational choice framework. By using this integrative approach, it is shown that, after a shock, the aspiration for conformity results in a steady state that deviates from the homo oeconomicus's behavior toward the consumption of the peer group, whereas the aspiration for consistency leads to the result that the steady-state consumption is not reached at once. With the combination of these effects, a new consumption path is derived. After a shock, the individual consumption converges step by step to the new steady-state consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

我国海上油田钻井完井投资测算方法研究

本文分析了我国海上油田钻井完井投资测算的现有方法,针对存在的问题和不足,从内生变量的选择、相关系数、变量的影响程度等方面进行分析研究,提出以作业周期、井深、水深三个因素进行测算的新方法。     

试论技术经济学的学科性质与理论基础

本文从技术经济的研究对象和研究角度出发,论述了技术经济学的学科性质属于经济学;技术经济学的理论基础是生产力经济学和政治经济学;在此基础之上,论述明确技术经济学学科属性及理论基础对推动技术经济研究和技术经济人才培养的重要意义.     

复关后纺织经济监测报警与预警系统

依据ＧＡＴＴ的原则及有关法律条款，考虑到“复关”后我国纺织经济将面临的有关实际问题，我们设计了旨在“复关”后，保护我国纺织工业在国际市场中的合法权益，促进我国纺织经济健康顺利发展的一套监测与报警预警系统。     

An Evolutionary Model of Endogenous Business Cycles

In this paper, we present an evolutionary model of industry dynamics yielding endogenous business cycles with ‘Keynesian’ features. The model describes an economy composed of firms and consumers/workers. Firms belong to two industries. The first one performs R&D and produces heterogeneous machine tools. Firms in the second industry invest in new machines and produce a homogenous consumption good. Consumers sell their labor and fully consume their income. In line with the empirical literature on investment patterns, we assume that the investment decisions by firms are lumpy and constrained by their financial structures. Moreover, drawing from behavioral theories of the firm, we assume boundedly rational expectation formation. Simulation results show that the model is able to deliver self-sustaining patterns of growth characterized by the presence of endogenous business cycles. The model can also replicate the most important stylized facts concerning micro- and macro-economic dynamics. Indeed, we find that investment is more volatile than GDP; consumption is less volatile than GDP; investment, consumption and change in stocks are procyclical and coincident variables; employment is procyclical; unemployment rate is anticyclical; firm size distributions are skewed but depart from log-normality; firm growth distributions are tent-shaped. JEL Classifications: C15, C22, C49, E17, E22, E32.     

Significance of a behavioral economic index of reward value in predicting drinking problem resolution.

This study investigated whether a behavioral economic index of the value of rewards available over different time horizons improved prediction of drinking outcomes beyond established biopsychosocial predictors. Preferences for immediate drinking versus more delayed rewards made possible by saving money were determined from expenditures prior to resolution attempts by problem drinkers with different help-seeking experiences (N = 144). As hypothesized, stable resolutions over a 2-year follow-up were associated with proportionally more preresolution discretionary expenditures on savings and less on alcohol compared with unstable resolutions. The relationship held regardless of help-seeking history, and preresolution drinking practices, problems, and income were similar across outcomes. The findings extend experimental work on behavioral economics and indicate that measuring monetary allocation improves prediction of outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)