Ecological chemistry and the palatability spectrum

A new bioassay for comparing the palatability to avian predators of monarch butterflies reared on various asclepiadaceous food plants containing cardiac glycosides indicates a palatability spectrum. The monarchs reared on one plant species are six times as emetic as those fed another, while those raised on an asclepiad which lacks cardiac glycosides are not emetic at all.     

The scientific advisory system: some observations

The scientific advisory system is effective on limited technical questions, and such questions provide much of its work. On broad technical questions, however, the scientific advisory system is not effective. Unfortunately this category includes most of the crucial environmental questions. Finally, the advisory system, as presently constituted, combined with the multiple functions of the scientific establishment, is detrimental in important ways to the process of technical decision-making in this country. This is because the combined effect of the advisory system and the establishment is to impede the development of a more effective and comprehensice role for the scientific community in the technical decision-making process.     

竹笋适口性形成及其主要影响因素研究综述

竹笋是中国传统森林蔬菜,也是大宗出口农产品。适口性体现了竹笋经济价值和市场潜力,是高品质竹笋评价的重要指标,但竹笋适口性形成基础及提升技术研发相对薄弱,一定程度上限制了竹笋品质改良技术研发及生产应用。本研究综述了竹笋适口性评价的主要指标,总结了当前竹笋适口性的主要研究成果,并对未来研究提出展望。目前竹笋适口性的研究主要集中于:①竹笋适口性的种间差异;②环境因子对竹笋适口性的影响;③经营措施对竹笋适口性的影响。主要结论为:糖、酸、酚类、纤维类以及氨基酸类物质是竹笋适口性评价的主要指标,适口性的形成不仅取决于竹种自身遗传因素,同时也受到气候因素和土壤质地等的影响。通过覆盖栽培、施肥、林分结构调控和选择适宜的采笋时间等途径可以改良竹笋适口性,但其效应存在明显的种间差异。未来竹笋适口性的研究应该集中于构建适口性综合评价指标与方法,探究多因素互作对竹笋适口性的影响,从生态、生理、生化、分子等多学科层面揭示竹笋适口性形成机制。筛选适口性好、产量高、生态适应性强的优良笋用竹进行规模化栽培,并从栽培环境选择、土壤养分精准补充、笋芽萌发环境控制、竹笋器官处理等途径研发竹笋适口性改良技术。参66     

Antbutterflies: butterflies that follow army ants to feed on antbird droppings

Females of three species of tropical rain forest ithomiine butterflies orient to swarms of army ants (Eciton burchelli) and feed on bird droppings found there. The antbirds associated with swarm raids of these ants provide a predictable source of droppings, an otherwise sparsely distributed resource.     

Carbon: observations on the new allotropic form

The recently characterized " white " allotropic form of carbon has been produced at high temperature and low pressure during graphite sublimation. Under free-vaporization conditions above approximately 2550 degrees K, the white carbon forms as small transparent crystals on the edges of the basal planes of graphite. The interplanar spacings of this material are identical to those of a carbon form noted in graphitic gneiss from the Ries Crater.     

皖南山区蝴蝶资源调查研究

对皖南山区蝴蝶资源进行了多年的研究,共采集鉴定蝴蝶资源12科、123属、292种,其中以蛱蝶科种类最多,达80种,占总数的27.4%;其余依次是眼蝶科49种、弄蝶科46种、灰蝶科43种、凤蝶科35种、粉蝶科25种,其它6个科种类极少.     

牛头河流域蝶类资源

报道了甘肃省天水市牛头河流域的蝶类67种名录，其中凤蝶科7种、粉蝶科13种、绢蝶科1种、灰蝶科7种、蛱蝶科24种、眼蝶科8种、弄蝶科7种。     

Uranus: variability of the microwave spectrum

Radio astronomical observations of Uranus show that the radio emission spectrum is evolving in time. Ammonia vapor must be depleted in the Uranian atmosphere as Gulkis and his co-workers previously suggested. Since 1965, ammonia either has been decreasing in time or is a decreasing function of latitude, or both, provided that the radio emission is atmospheric in origin. If Uranus has an observable low-emissivity "surface," these trends may be reversed. The microwave observations made in 1965, at the time when the spin axis of Uranus was nearly perpendicular to the sun-Uranus line, are consistent with an atmospheric opacity profile that would be produced by saturated ammonia vapor in a predominantly hydrogen atmosphere. At the present time, when the spin axis of Uranus is nearly aligned with the sun-Uranus line, the measurements require an opacity that would be produced by saturated water vapor. A large thermal gradient between the pole and equator is ruled out.     

甘肃蝶类二新记录种

经对甘肃省蝶类资源调查,发现甘肃省新记录二种:褐钩凤蝶风伯亚种Meandrusa sciron aribbas和黑紫蛱蝶Sasakia funebris.     

Pulsars: observations of spectra

Dynamic spectrograms of two of the recently discovered pulsating radio sources have been obtained. The data provide the instantaneous spectrum and the time-frequency history of the signals over a bandwidth of 3 megahertz.     

皂甙对动物生长的影响概述

皂甙(saponins)又名皂苷或者皂素,是甾体或者三萜系化合物的低聚配糖体总称,因其水溶液能形成持久泡沫,象肥皂一样而得名.其普遍存在于许多植物和植物产品中,这些植物和植物产品是人和动物重要的营养物质.皂甙由糖及非糖部分(糖苷配基)组成,皂甙结构的复杂性源于糖苷配基的多样性.     

Insects as selective agents on plant vegetative morphology: egg mimicry reduces egg laying by butterflies

Experiments show that Heliconius butterflies are less likely to oviposit on host plants that possess eggs or egglike plant structures. These egg mimics are an unambiguous example of a plant trait evolved in response to a host-restricted group of insect herbivores.     

Comparative losses of British butterflies, birds, and plants and the global extinction crisis

There is growing concern about increased population, regional, and global extinctions of species. A key question is whether extinction rates for one group of organisms are representative of other taxa. We present a comparison at the national scale of population and regional extinctions of birds, butterflies, and vascular plants from Britain in recent decades. Butterflies experienced the greatest net losses, disappearing on average from 13% of their previously occupied 10-kilometer squares. If insects elsewhere in the world are similarly sensitive, the known global extinction rates of vertebrate and plant species have an unrecorded parallel among the invertebrates, strengthening the hypothesis that the natural world is experiencing the sixth major extinction event in its history.     

Mars: correlation of optical and radar observations

A comparsion of recent photographic and radar data on Mars indicates a good positive correlation between dark areas and radar reflection peaks and also between cloudy "desert" areas and radar minima. The data may be taken as evidence that dark areas are, in general, relatively smooth whereas deserts are relatively rough.     

Viking bistatic radar observations of the hellas basin on Mars: preliminary results

Preliminary reduction of Viking bistatic radar data gives root-mean-square surface slopes in the Hellas basin on Mars of about 4 degrees on horizontal scales averaged over 10 centimeters to 100 meters. This roughness decreases slightly with position along the ground track, south to north. The dielectric constant in this area appears to be approximately 3.1, greater than the martian average. These values are characteristic of lunar maria and are similar to those found near the Viking lander site in Chryse with the use of Earth-based radar.     

Mercury: observations of the 3.4-millimeter radio emission

Observations of the 3.4-millimeter radio emission from Mercury during 1965 and 1966 yielded the following relationship between average brightness temperature T(B) of the disk and the planetocentric phase angle i: T(B) = 277 (+/- 12) + 97 (+/- 17) cos [i + 29 deg (+/- 10 deg)] degrees K The errors are statistical standard; the phase shift corresponds to a phase lag-that is, the maximum and minimum of insolation lag the maximum and minimum of planetary radiation.     

串叶松香草饲喂牛羊等的适口性及饲喂方法试验

通过用串叶草饲喂牛、羊等适口性及饲喂方法的试验，结果表明，串叶草饲喂草食家畜，适口性较禾本科差，但让其适应几天后，采食量可逐步提高。不同生育期对同一家畜适口性不同，串叶草饲喂牛、羊的适宜期为抽苔期40～80cm。不同处理方式，不同饥饿程度务件下牛、羊对串叶草的适口性、采食量不同。用串叶草喂牛宜在半饥饿状态下切碎饲喂，八九成饱时，饲喂其它草，若全天喂串叶草，可喷0．2％盐水饲喂；喂羊在八九成饱时，伴香味剂、甜味剂诱食。若与精料搭配饲喂，喂牛以精青比5．3％为宜，喂羊以精青比7．5％为最佳。用串叶草鲜草和草粉代替部分日粮饲喂奶牛，能使其产奶量有所提高。