临时收储政策改革背景下玉米盈利能力与生产率

基于2000-2018年“东北三省一区”的投入产出面板数据和O’ Donnell提出的加总价格-数量框架,采用Färe-Primont生产率指数分析临储政策的实施及改革对玉米盈利能力及其组成部分的影响,探究玉米盈利能力变化的动力源泉。研究发现,临储政策实施后,临储地区玉米盈利能力降低,其原因是产出-投入相对价格(TT)大幅下降,全要素生产率(TFP)则增长缓慢。临储政策虽大幅提高了玉米价格,但同时也造成了土地租金的大幅增长,再加上劳动力价格的上涨,共同导致了TT的大幅下降。临储政策改革后,临储地区玉米盈利能力持续降低,由TT和TFP的下降共同驱动。临储政策改革还表现出较强的时间异质性,价补分离政策能够有效缓解临储政策取消对农民利益的冲击。     

吉林省玉米价格波动及其影响因素分析

吉林省自2008年实施玉米临时收储政策,导致玉米市场出现国内外玉米价格倒挂、玉米加工企业成本骤增等问题。利用波动理论对1981~2014年吉林省玉米价格波动进行分析,结果表明,吉林省玉米价格波动相对较频繁,短周期波动明显,存在严重恶性波动。进一步分析影响吉林省玉米价格波动因素,国家政策对吉林省玉米价格影响最大,逐年上升的"托市价格"导致玉米供给水平对玉米价格的传导为负向,玉米生产成本、国际玉米市场和玉米需求情况对玉米价格产生正向影响。为推动玉米临时收储价格改革,稳定玉米市场价格,提出建立玉米目标价格补贴制度、完善玉米市场监测预警机制、降低玉米生产成本等对策建议。     

我国糖料作物种植与食糖产业发展分析

介绍了我国糖料作物种植、食糖生产和消费、食糖市场供需及价格变动、食糖产业政策及贸易政策等情况,对促进我国食糖产业的发展具有一定的意义.     

我国玉米进出口市场势力的变化分析

从临时收储政策到“价补分离”政策,玉米市场化改革逐步深入。为了测度我国玉米在国际进出口市场上是否存在市场势力,本文利用“看市定价”模型,基于理论和实证视角分析玉米支持政策变化前后我国玉米在国际市场上的定价权。回归结果表明,在实行玉米“价补分离”政策后,汇率对我国玉米进出口价格的影响显著,政策对我国玉米进出口价格的影响为负向。在玉米“临储政策”改革后,我国的玉米进出口价格下降,同时在玉米出口市场上呈现出较弱的市场定价权。因此,我国仍需从降低玉米生产成本、提高玉米生产品质、持续推动政策实施以及完善玉米种植保险等方面入手,增大可获取利润的空间,从而获得更有利的贸易条件。     

新常态下完善新疆棉花目标价格补贴政策的思考

新常态下国内棉花产业面临诸多机遇和挑战,特别是2014年以来,国家连续两年在新疆实施棉花目标价格补贴政策,为完善我国农产品市场调控政策体系积累了宝贵的经验。梳理近年来国内棉花产业面临的新常态,分析了目标价格政策的作用机制,总结政策实施效果和问题,并为完善操作办法和措施提出建议。     

完善我国棉花目标价格政策的思考和建议

2014年我国在新疆开始实施棉花目标价格补贴试点工作,对稳定新疆棉花生产、完善农产品市场调控政策体系发挥了积极的作用。在充分调研的基础上,梳理近年来我国棉花主要市场调控政策,总结发达国家目标价格政策经验,系统分析政策作用机制及问题,并提出对策建议。     

糖业目标价格政策的国际经验及对我国的启示

将食糖主产国划分为供需基本平衡型、进口主导型、出口导向型国家,通过系统梳理三类国家糖业调控政策的国际经验,尤其是供需基本平衡型与进口主导型国家的糖业目标价格政策的实施方案,对我国糖业发展带来几点启示,进而为我国糖业目标价格政策的实施提供了几种不同的方案设计,结合本国国情、糖业发展目标、实施难度、可操作性等情况,短期来看借鉴方案一实施目标价格最具现实性,中长期来看提升国际竞争力才是我国糖业发展的根本出路。     

关于新疆棉花目标价格补贴试点政策的探讨

从2014年开始,国家改革了棉花市场调控政策,在新疆实施棉花目标价格补贴试点。本文在分析新疆棉花生产情况的基础上,探讨了棉花目标价格补贴试点的总体思路、关键问题及建议。     

基于社会福利的新疆棉花目标价格补贴政策研究

棉花价格的剧烈波动导致“棉贱伤农”“棉贵伤纺”的现象时有发生，为此，国家试点棉花目标价格政策，以平抑棉价波动、稳定棉花生产、增加全社会福利。本文在介绍2014年棉花目标价格政策主要内容的基础上，重点分析此次改革的社会福利效应。研究发现：目标价格补贴政策能够有效地增加社会福利，但目标价格的确定、政策实施的效率都将影响社会福利水平。因此，提出及时发放补贴资金、实施棉花综合补贴、完善期货市场的对策。     

我国粮食种子安全问题的调研与思考

对我国粮食种子安全问题进行了调研和探讨.目前我国粮食作物种子产业存在种子需求量增加；种子供需不平衡,种子价格急剧波动；品种结构多乱杂；种子质量不能有效保证,种子纠纷隐患多等问题.其产生原因主要是种子市场化调控难度大；种子生产受生态条件限制,自然灾害频繁,防范能力差；种子科技投入少,成果转化慢.今后应提高认识,加强领导；严格把关,强化种子产业监管；加大种子科技投入,促进种子科技创新；健全种子产业机制,确保种子安全.     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.