运用人工神经网络作汛期降水预报

本文提出汛期降水预报的人工神经网络方法，并选择一组标样进行了具体分析，预报成功率达100％，结果表明，该方法性能良好，可望成为汛期降水预报的有效手段。     

The reproductive phenology of Isoetes lacustris L.: Results of field studies in Scandinavian lakes

The phenologic change of the leaf rosette structure of Isoetes lacustris L. was studied in 26 lakes of temperate, boreal, or subarctic Scandinavia between 59° and 70° n.l. The investigations were carried out during six defined seasons: late winter, spring, early summer, late summer, autumn, and early winter. From 640 plants, gained with the aid of SCUBA, six leaf types were distinguished: immature megasporophylls, mature megasporophylls, immature microsporophylls, mature microsporophylls, and sporophylls that had released their spores and leaves with undeveloped sporangia. Mean numbers per rosette of each leaf type were established in each study lake and study season, resulting in a common pattern embracing all lakes studied.

Megasporophylls are developed throughout the year, whenever the water temperature is about 10 °C. Their share was always more than 30%, excepting winter. Microsporophylls are produced preferentially in spring/early summer when the days are longest; they amount to more than 50% of the rosette leaves during this period, but only to some 10% in the remaining seasons. The spores mature and are released between late summer and early winter. It is concluded that not all spores mature in the year of their birth, and those that do not mature are released in the early summer of the following year, as well as the old empty leaves become detached.     

吐鲁番地区旅游气候指数及评价

旅游气候资源是旅游事业开发中极为重要的资源之一,本文通过对吐鲁番地区的主要旅游气候资源的评价,指出吐鲁番地区除葡萄沟景区以外的其他人文和自然景观应提倡四季游,为进一步拓展吐鲁番地区旅游业的发展空间提供了科学依据。     

Seasonal, Geographical and Size Differences in Oxygen Consumption, Digestive Gland and Gills in Carcinus maenas (L), a Study of Condition for Ecologists

Abstract. The excited rate of oxygen consumption, and the wet weights of the digestive gland and the gills were studied in relation to overall size. One experiment was made in Roscoff, France, one in Portaferry, N. Ireland, and three in Wicklow, Ireland. Higher levels of oxygen consumption were found in Roscoff together with greater gill weight. Seasonal changes in the level of oxygen consumption in Wicklow may be influenced by the dry wt/wet wt ratio of the gills - probably an index of condition for the crabs as a whole. The power functions for allometric growth were virtually constant for each factor in all five experiments. All levels of factors were reduced in males weighing more than 60 g. Disproportions in the weights of the chelae marked the populations in Roscoff and Portaferry, compared with Wicklow. These suggest a genetic basis for the geographical differences in oxygen consumption and gill weight. The importance of local experiments for local conditions and the possibilities for predicting physiological rates from morphology are discussed.