高氟环境对奶牛生产和繁殖性能的影响

通过检测宁夏某地奶牛内外环境中的饮水、饲料和土壤氟、硒、铜及血氟、毛氟、尿氟和全血硒、铜，证实该场奶牛高氟低硒低硐。日粮添加０。２６ｍｇ／ｋｇ硒和３．２ｍｇ／ｋｇ铜。连续饲喂３个月，低硒低铜现象消失，但高氟仍旧存在。高氟使奶牛子宫复旧时间、首次发情时间 科后配妊天数分别延长６．６ｄ、６ｄ和３８．５ｄ，产后孕酮含量始终低于健康奶牛，同时，奶牛胎衣不下发病率和乳房炎发病率分别高于健康奶牛１６．７％和１     

Deep chlorophyll maximum distribution in the central Tyrrhenian Sea described by a towed undulating vehicle

The towed undulating vehicle (TUV), named SARAGO, was used for two fine-scale surveys between the Italian and the Sardinian coasts during the Astraea 2 cruise (6–7 and 26–27 September 1995), studying the deep chlorophyll maximum distribution. SARAGO sections identify a sub-surface doming with higher chlorophyll a and primary production concentrations in the upwelling area of a cyclonic gyre region, detected by sea-surface temperature images. In the first section, the cyclone presents a double doming, in density and salinity, with shallower and concentrated patches of chlorophyll a for about 2 miles. Twenty days later, the second section shows that the gyre changes shape and extension, showing a single doming with higher primary production and chlorophyll a concentrations, distributed over a large area of about 40 nautical miles. SARAGO allows analysis of this high-variability phenomenon (cyclonic gyre) and allows concentrated patches (2 nm) to be identified, thus proving the importance of TUVs in the study of mesoscale processes.     

Restoration of the Marine Ecological Environment Along the Charting Coast: Primary Productivity and Biomass Study

Since 1986, when green oysters occurred due to the copper and organic pollution in the Charting coastal area, the government banned all maricultural activity. It has been claimed that growing algae in a polluted environment may clean the water of pollutants and restore the marine ecosystem. to test this hypothesis, in the Charting coastal area a three-year programme (from August 1992 to July 1995) was carried out. the survey programme included environmental components such as salinity, temperature, pH, dissolved oxygen, biological oxygen demand (BOD), particulate organic carbon (POC), heavy metals and ecological indicators such as nutrients, chlorophyll-a, primary productivity. in the first year study, the environmental background data collected was used to select the suitable season and locations for growing large algae transferred from the laboratory to the field study area. Since September 1993, various species of large algae have been cultured. Although some of the growing algae were damaged by a typhoon in August 1994, the impact of the growing algae on the environmental conditions in the area has been monitored throughout. Elsewhere, we have reported that in the algae growing area higher dissolved oxygen with lower values of BOD and POC were found, and the concentrations of heavy metals in both water and sediments decreased. the purpose of this paper is to evaluate the possible impact of growing large algae on the ecological conditions in Charting coastal waters through the period from August 1983 to May 1995. As a result of the positive results obtained, large amounts of algae have again been cultured in the same area during the period from April 29 to May 25, 1995. We expect that inorganic and organic pollutants will be reduced by the algal growth, oyster mariculture will be restored and finally, the fishery resources potential will be increased.     

Is mining a high-tech industry?: Investigations into innovation and productivity advance

The fundamental nature of the mining industry with respect to innovation is often questioned. Is it the conservative, stodgy industry commonly depicted by its critics or is it instead a sophisticated, high-tech industry as championed by many of proponents? Using productivity statistics, it can be shown that the innovation rate of metal mining companies directly compares with the rates associated with general manufacturing. This relationship has held true for the last 50 years. A significant difference lies in the high-tech manufacturing sector, which for the last approximately dozen years has held productivity increases of 9.5% per year, in contrast to general manufacturing and metal mining rates of 2.5% and 2.3% per year, respectively.     

CO2 emissions in calcium carbide industry: An analysis of China's mitigation potential

China's calcium carbide output has dominated the global market for several years, driven by the demand for PVC (polyvinyl chloride), a fundamental polymer material and also the primary downstream product of calcium carbide in China. The fast growth of this energy-intensive industry leads to an inevitable increase in CO₂ emissions. However, there is a large reduction potential with process improvement in this industry which is currently characterized by widespread outdated facilities. In this study, we attempt to assess the reduction potential of CO₂ emissions in China's calcium carbide production, based on the analysis of CO₂ emission patterns and estimation of the emission amount. Three scenarios regarding process improvement are employed to conduct this assessment. The results imply that the cumulative CO₂ abatement in the Current Policy Scenario and in the Strengthened Policy Scenario from 2008 to 2020, compared with the Baseline Scenario, are 89.0 and 107.6 million t, respectively. The specific measures and policy implications to achieve this potential are also discussed in the article.     

An energetic perspective on the relationship between disturbance and ecosystem productivity

Previous ecological models for disturbance from energetic perspectives have focused on destructive pulses by which storages in a system are quickly drained during disturbance events and recovered thereafter. However, considering the wide range of disturbance intensities, frequencies, and durations in nature, disturbance effects on ecosystem energetics would be better understood by diversifying the disturbance effects on specific system configurations or energy pathways. Based on two hypotheses, we built simulation models of the variable disturbance-productivity relationships observed in a freshwater aquatic microcosm study. First, we hypothesized that disturbances will differentially alter the intrinsic rates of energy pathways in a system. Second, we hypothesized that there is a disturbance threshold where response of the intrinsic rates changes abruptly. Simulation results showed variable patterns of gross primary productivity (GPP) during the disturbance and post-disturbance periods under the diverse scenarios of disturbance effects on the intrinsic rates. Simulation results confirmed that the second hypothesis (i.e., disturbance threshold) was essential to achieve a U-shaped or peaked disturbance-productivity relationship. We evaluated the models by comparing them with the results of the microcosm tests, and suggested possible mechanisms of the variable disturbance-productivity relationships by varying parameters related to the disturbance effects on the intrinsic rates and the disturbance thresholds.     

Long-term trends in the Real real prices of primary commodities: Inflation bias and the Prebisch–Singer hypothesis

In his recent article on measuring the long-term trends in the real prices of primary commodities, Cuddington (2010) extends in several important respects our earlier efforts (Svedberg and Tilton, 2006) to correct real commodity price trends for biases in the Consumer Price Index and other deflators. First, he argues for a log-linear relationship between prices and time. Second, he proposes a simple and quick method for obtaining corrected price trends from the published but uncorrected estimates. Finally, he illustrates, for the case of copper and presumably for many other commodities as well, the difficulties of obtaining real price trends significantly different from zero when the log values of the price data contain a unit root, requiring the use of difference stationary models.We welcome these insights, which should improve and make easier efforts to estimate correctly real commodity price trends over the long run. We would stress, however, that it is still important to correct for the biases in inflation indices, notwithstanding the failure of difference stationary models to obtain long-run real price trends (both corrected and uncorrected) significantly different from zero.