高职食品专业校企合作的问题及对策

校企合作教育是一种充分利用学校与企业等多种不同的教育环境和资源在培养人才方面的优势,培养适应企业需要的应用性专门人才的教育模式,对高职院校培养应用型人才具有重要的意义。但当前高职院校的校企合作中存在如政策法规不健全、合作机制不完善、企业的热情不高等问题,针对这些问题从政府政策、企业和学校三方面对其解决方法提出了建议。     

The effects of ethylene chlorohydrin on fatty acid synthesis 1 2 3

Abstract

Male chicks weighing 700 to 900 g. received an acute or eight doses IG of 60 or 40 mg/kg ethylene chlorohydrin (ECH) respectively and were sacrificed eighteen hours after the last dose. Mitochondrial elongation of fatty acids was decreased significantly while fatty acid synthetase activity was not significantly affected by ECH treatment. Cytochrome c oxidase activity in fresh whole liver homogenate was significantly higher in chicks subjected to acute exposure with ECH when compared to the controls. Upon freezing and thawing of homogenates, cytochrome c oxidase activity increased significantly in the control group but was unchanged in the ECH group which suggests that the mitochondrial membrane integrity is compromised by the ECH treatment. Serum and liver triglyceride levels were significantly elevated in both the single and multiple ECH dose groups. Liver to body weight ratios were significantly higher in both treatment groups when compared to their controls. Histological examination of the liver of ECH‐treated chicks showed cytoplasmic clearing of the cells but no vacuolization or centri‐lobular necrosis. Serum isocitrate dehydrogenase levels were significantly higher in the multiple treatment ECH group than in the control group.     

Trace Metals in Upland Headwater Lakes in Ireland

Trace elements (n = 23) in Irish headwater lakes (n = 126) were investigated to determine their ambient concentrations, fractionation (total, dissolved, and non-labile), and geochemical controls. Lakes were generally located in remote upland, acid-sensitive regions along the coastal margins of the country. Total trace metal concentrations were low, within the range of natural pristine surface waters; however, some lakes (~20 %) had inorganic labile aluminum and manganese at levels potentially harmful to aquatic organisms. Redundancy analysis indicated that geochemical weathering was the dominant controlling factor for total metals, compared with acidity for dissolved metals. In addition, many metals were positively correlated with dissolved organic carbon indicating their affinity (or complexation) with humic substances (e.g., aluminum, iron, mercury, lead). However, a number of trace metals (e.g., aluminum, mercury, zinc) were correlated with anthropogenic acidic deposition (i.e., non-marine sulfate), suggesting atmospheric sources or elevated leaching owing to acidic deposition. As transboundary air pollution continues to decline, significant changes in the cycling of trace metals is anticipated.     

Review of advances in the thin layer chromatography of pesticides: 2006–2008

Applications of thin layer chromatography and high performance thin layer chromatography for the separation, detection, qualitative and quantitative determination, and preparatire isolation of pesticides and their metabolites are reviewed for the period from July 1, 2006 to November 1, 2008. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue and formulation analysis, studies such as pesticide-structure relationships, identification and characterization of plant pesticides, metabolism, degradation, mobility, and lipophilicity are covered. Future prospects for pesticide thin layer chromatography are also considered.     

Bioaccumulation of mercury in the trophic chain of flatfish from the Baltic Sea

Mercury concentrations in three flatfish species - flounder (Platichtys flesus), plaice (Pleuronectes platessa), and Baltic turbot (Scophthalmus maximus), netted in the southern Baltic Sea were assessed and compared to concentrations of this metal in sediments, sea water, and flatfish food - bivalve Macoma balthica, isopod Saduria entomon, and sprat (Sprattus sprattus). Collected simultaneously with flatfish in 2009 and 2010. Different concentrations of mercury depending on species, tissue or organ, sex, individual length, kind of food, and region were determined. The muscle tissues of turbot had the highest concentrations of the metal. The bioaccumulation (BF) and biomagnification (BMF) factors has been counted showing that the muscle tissues of turbot have maximum affinity for mercury, and thus best reflected the metal contamination of the Baltic Sea environment. The data suggest that the common Baltic turbot (S. maximus) is an important model species, suitable and cost-effective to biomonitor environmental mercury pollution for ecological research.     

粮食安全:气候变化与粮食产地转移

基于1985-2008年中国雀际面板数据,实证检验了气候变化对粮食种植规模与单位产量的作用机制,进而分析了产地转移对国家粮食总供给的影响.结论表明:①中国的稻谷、小麦、玉米产业正分别向黑龙江、河南、内蒙古等气候资源匮乏地区转移或集聚;②粮食产地转移的主导因素在于粮食作物与经济作物、种植业与畜牧业、农业与非农的成本收益比较,而气候变化因素仅处于附属地位;③基于规模效应、牧入效应以及回弹效应的作用机制,东北三省、河南、内蒙古等地区的增长潜质往往优于其他地区;④落后地区应对气候变化的生产与政策成本,往往要低于发达地区保留粮食生产的机会成本,粮食生产向欠发达地区转移应具有可持久性.粮食产地转移过程中,并未呈现粮食供给安全的“个体理性”与“集体理性”的冲突.中国应该在气象预报、水利设施、抗灾能力、中低产田改造等方面加大投入,摒弃区内平衡的传统观念,在全国范围内优化资源配置,并辅以国家粮食储备战略应对特大灾害的供给风险.     

Governance of Complex Socio-Environmental Risks: The Case of Hazardous Chemicals in the Baltic Sea

Complex socio-environmental risks challenge society. In response to scientific uncertainty and socio-political controversies, environmental governance, precaution, and the ecosystem approach to management are held forward as complements to governmental risk-based sector-restricted regulation. We analyze this development for hazardous substances in the Baltic Sea. Based on interviews and policy analysis, we study informal governance and, in particular, four central EU and international policies, and investigate how present governance relates to risks and objectives at hand. While showing emergence of broader governance approaches, we conclude that central objectives will not likely be met. Furthermore, we question the quest for broad environmental governance and emphasize the value of command and control regulation, if it implements precaution. These findings contribute to the theorizing on environmental (risk) governance. Finally, we provide some ideas that could help development and implementation of risk policies for hazardous chemicals in the Baltic Sea as well as other complex risks.     

Hexabromocyclododecanes (HBCDs) in marine fishes along the Chinese coastline

This study reports concentrations of hexabromocyclododecanes (HBCDs) in two species of marine fish, large yellow croaker (Pseudosciaenacrocea) and silver pomfret (Pampusargenteus) (n = 46), from nine Chinese coastal cities (Dalian, Tianjin, Qingdao, Shanghai, Zhoushan, Wenzhou, Fuzhou, Quanzhou and Xiamen). HBCDs were detectable in all samples analyzed, indicating ubiquitous contamination of these compounds in the Chinese coastal environment. The average total HBCD concentration was 3.7 ng g⁻¹ lipid weight (range: 0.57-10.1 ng g⁻¹ lipid weight), which is relatively lower than other regions of the world, especially Europe, where HBCDs are intensively used. Among the three individual HBCD isomers (α-, β- and γ-HBCD) in all fish samples, the α-isomer showed a remarkable predominance (from 87.5% to 100% of total contribution), indicating its higher bioaccumulative potential. Geographically, the highest HBCD level present in fish was found in Dalian in northern China, and the lowest occurred in Wenzhou. Estimated daily intakes of HBCDs via fish consumption for the Chinese population were 0.004-1.00 ng kg body weight⁻¹ d⁻¹. These exposure levels were much lower than the effect levels.     

Validation of a GC-MS/MS method for simultaneous determination of 86 persistent organic pollutants in marine sediments by pressurized liquid extraction followed by stir bar sorptive extraction

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography-triple quadrupole mass spectrometry (TD-GC-MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log K_ow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g⁻¹, with detection limits below pg g⁻¹ levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC-MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).     

Organochlorine pollution in tropical rivers (Guadeloupe): role of ecological factors in food web bioaccumulation

Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon were measured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examine the bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a general and heavy contamination of the entire food web. They revealed the strong accumulation of pollutants by juveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in the bioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone and monohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of β-HCH was only influenced by animal lipid content. The biomagnification potential of chlordecone through the food chain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulation process. In contrast, bioconcentration by passive diffusion from water seemed to be the main exposure route of biota to β-HCH.