A stage in female development: girls at puberty     

Unger RK 《Science (New York, N.Y.)》1984,224(4650):722

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Eco‐efficiency as a strategy for optimizing the sustainability of pest management     

Roger D Magarey  Sarah SH Klammer  Thomas M Chappell  Christina M Trexler  Godshen R Pallipparambil  Ernie F Hain 《Pest management science》2019,75(12):3129-3134

Agricultural industrialization and the subsequent reliance on pesticides has resulted in numerous unintended consequences, such as impacts upon the environment and by extension human health. Eco‐efficiency is a strategy for sustainably increasing production, while simultaneously decreasing these externalities on ecological systems. Eco‐efficiency is defined as the ratio of production to environmental impacts. It has been widely adopted to improve chemical production, but we investigate the challenges of applying eco‐efficiency to pesticide use. Eco‐efficiency strategies include technological innovation, investment in research and development, improvement of business processes, and accounting for market forces. These components are often part of integrated pest management (IPM) systems that include alternatives to pesticides, but its implementation is often thwarted by commercial realities and technical challenges. We propose the creation and adoption of an eco‐efficiency index for pesticide use so that the broad benefits of eco‐efficient strategies such as IPM can be more readily quantified. We propose an index based upon the ratio of crop yield to a risk quotient (RQ) calculated from pesticide toxicity. Eco‐efficiency is an operational basis for optimizing pest management for sustainability. It naturally favors adoption of IPM and should be considered by regulators, researchers, and practitioners involved in pest management. © 2019 Society of Chemical Industry  相似文献   

Rapid sedimentological and biological assessment of hydrocarbon contaminated sediments     

Robert J. Diaz  Lars Johan Hansson  Rutger Rosenberg  Paul C. Gapcynski  Michael A. Unger 《Water, air, and soil pollution》1993,66(3-4):251-266

It is possible to rapidly detect the presence of high concentrations of sediment associated hydrocarbons using a sediment profile camera and simultaneously evaluate the general sedimentological and biological character of a contaminated area. In sediments that were heavily contaminated with hydrocarbons from spills and chronic long-term additions the presence of hydrocarbons was seen about 50% of the time in the sediment profile images as unique features, ‘H spots’. The presence of these features was related to the concentration of hydrocarbons in the sediment. In highly contaminated muddy sediments ‘H spots’ were found in images collected at stations that had from 270 to 610 ppt total hydrocarbons. Sedimentological and biological information obtained from the sediment profile images confirmed the impacted nature of Elizabeth River sediments. Sediment profile imaging provide a means of obtaining an overall evaluation of the quality of a habitat and impacts on that habitat from pollution related environmental disturbances. While qualitative, an advantage of sediment profile image data is that they can be evaluated in less than a day and used to quickly locate inclusions of hydrocarbons in the sediments for further quantitative chemical or biological sampling, or mapping of heavily contaminated areas.  相似文献   

Plants as de-worming agents of livestock in the Nordic countries: historical perspective, popular beliefs and prospects for the future.     

PJ Waller  G Bernes  SM Thamsborg  A Sukura  SH Richter  K Ingebrigtsen  J H?glund 《Acta veterinaria Scandinavica》2001,42(1):31-44

Preparations derived from plants were the original therapeutic interventions used by man to control diseases (including parasites), both within humans and livestock. Development of herbal products depended upon local botanical flora with the result that different remedies tended to develop in different parts of the world. Nevertheless, in some instances, the same or related plants were used over wide geographic regions, which also was the result of communication and/or the importation of plant material of high repute. Thus, the Nordic countries have an ancient, rich and diverse history of plant derived anthelmintic medications for human and animal use. Although some of the more commonly used herbal de-wormers were derived from imported plants, or their products, many are from endemic plants or those that thrive in the Scandinavian environment. With the advent of the modern chemotherapeutic era, and the discovery, development and marketing of a seemingly unlimited variety of highly efficacious, safe synthetic chemicals with very wide spectra of activities, herbal remedies virtually disappeared from the consciousness--at least in the Western world. This attitude is now rapidly changing. There is a widespread resurgence in natural product medication, driven by major threats posed by multi-resistant pest, or disease, organisms and the diminishing public perceptions that synthetic chemicals are the panacea to health and disease control. This review attempts to provide a comprehensive account of the depth of historical Nordic information available on herbal de-wormers, with emphasis on livestock and to provide some insights on potentially rewarding areas of "re-discovery" and scientific evaluation in this field.  相似文献   

Ultrasonographic biometry of the normal eye of the Persian cat     

A Mirshahi  SH Shafigh  M Azizzadeh 《Australian veterinary journal》2014,92(7):246-249

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烟草生产全程机械化作业研究     

余铭华  林绍武  施恩  郝东  徐恒光  李静超  李名荣 《湖南农业科学》2014,(20)

为了探索烟叶生产过程中各机械的性能及工作效率,2013年在福建省建阳市莒口镇河坝新村开展了烟叶生产全程机械化作业试点研究。结果表明,起垄环节,碎土率方面邵武华友履带式起垄机表现最好(89.9%),沟底积土方面松溪永顺表现最好;覆膜环节,各测试机型表现中等,在效率方面优于人工覆膜;移栽环节,漏栽率上江苏久泰移栽机高于江苏井关移栽机;培土环节,漳州南冠培土机操作简便,掉头灵活,单人操作,单行双侧作业,深受烟农喜爱;拔杆环节,龙岩诚德拔杆机单人操作,操作简便,动力较足,拔杆顺畅,拔杆带土较少,效果较好,适应性较强。  相似文献   

The influence of precipitation pulses on soil respiration - Assessing the “Birch effect” by stable carbon isotopes     

Stephan Unger  Cristina Máguas  Teresa S. David 《Soil biology & biochemistry》2010,42(10):1800-1810

Sudden pulse-like events of rapidly increasing CO₂-efflux occur in soils under seasonally dry climates in response to rewetting after drought. These occurrences, termed “Birch effect”, can have a marked influence on the ecosystem carbon balance. Current hypotheses indicate that the “Birch” pulse is caused by rapidly increased respiration and mineralization rates in response to changing moisture conditions but the underlying mechanisms are still unclear. Here, we present data from an experimental field study using straight-forward stable isotope methodology to gather new insights into the processes induced by rewetting of dried soils and evaluate current hypotheses for the “Birch“-CO₂-pulse. Two irrigation experiments were conducted on bare soil, root-free soil and intact vegetation during May and August 2005 in a semi-arid Mediterranean holm oak forest in southern Portugal. We continuously monitored CO₂-fluxes along with their isotopic compositions before, during and after the irrigation. δ¹³C signatures of the first CO₂-efflux burst, occurring immediately after rewetting, fit the hypothesis that the “Birch” pulse is caused by the rapid mineralization of either dead microbial biomass or osmoregulatory substances released by soil microorganisms in response to hypo-osmotic stress in order to avoid cell lyses. The response of soil CO₂-efflux to rewetting was smaller under mild (May) than under severe drought (August) and isotopic compositions indicated a larger contribution of anaplerotic carbon uptake with increasing soil desiccation. Both length and severity of drought periods probably play a key role for the microbial response to the rewetting of soils and thus for ecosystem carbon sequestration.  相似文献   

Der Einfluß hoher N-Gaben auf die zellulolytische Aktivität des Bodens sowie Beziehungen zwischen Mikroorganismentätigkeit und Ertragsleistung einer Weide     

Horst Unger 《Archives of Agronomy and Soil Science》2013,59(1-3):215-232

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Monolithic microfabricated valves and pumps by multilayer soft lithography     

Unger MA  Chou HP  Thorsen T  Scherer A  Quake SR 《Science (New York, N.Y.)》2000,288(5463):113-116

Soft lithography is an alternative to silicon-based micromachining that uses replica molding of nontraditional elastomeric materials to fabricate stamps and microfluidic channels. We describe here an extension to the soft lithography paradigm, multilayer soft lithography, with which devices consisting of multiple layers may be fabricated from soft materials. We used this technique to build active microfluidic systems containing on-off valves, switching valves, and pumps entirely out of elastomer. The softness of these materials allows the device areas to be reduced by more than two orders of magnitude compared with silicon-based devices. The other advantages of soft lithography, such as rapid prototyping, ease of fabrication, and biocompatibility, are retained.  相似文献   

Diabetic hyperglycemia: link to impaired glucose transport in pancreatic beta cells   总被引：23，自引：0，他引：23  

R H Unger 《Science (New York, N.Y.)》1991,251(4998):1200-1205

Glucose uptake into pancreatic beta cells by means of the glucose transporter GLUT-2, which has a high Michaelis constant, is essential for the normal insulin secretory response to hyperglycemia. In both autoimmune and nonautoimmune diabetes, this glucose transport is reduced as a consequence of down-regulation of the normal beta-cell transporter. In autoimmune diabetes, circulating immunoglobulins can further impair this glucose transport by inhibiting functionally intact transporters. Insights into mechanisms of the unresponsiveness of beta cells to hyperglycemia may improve the management and prevention of diabetes.  相似文献