βCephei变星的脉动不稳定带的研究(英文)

在本文中我们对两种不同的 βCephei变星的理论脉动不稳定带作了比较。它们具有明显的不同之处。为了确定这种变星的脉动不稳定带的轮廓 ,我们根据 4 9颗 βCephei变星的观测资料作了统计研究。在从样本星的色指数 (B -V) ,(U -B)和视差得到它们的有效温度和光度之后 ,我们发现在赫罗图上它们大多数是位于主序带内的。而且这些样本星的质量都位于 7M⊙ 到 30M⊙ 之间。和理论模型的比较表明我们提出的具有光度上边界和红蓝边界的 βCephei变星的理论脉动不稳定带跟观测吻合得更好     

尼罗罗非鱼对不同颜色定置网片的反应特性

本文初步研究了尼罗罗非鱼对红、黄、绿、蓝、青灰色定置网片反应特性,并探讨了该鱼对青灰色网片的适应特性。结果表明:绿色网片对罗非鱼的阻拦作用最大,青灰色网片次之,红、黄色网片再次,蓝色网片最小。罗非鱼对青灰色网片具明显的适应现象,它们完成整个适应过程所需的实验重复次数约为7次。     

新疆乌什北山沉积型铝土矿地质特征及找矿标志

乌什北山铝土矿为沉积型,铝土矿主要形成于中石炭世.其找矿标志有地层﹑矿体颜色﹑岩石结构、放射性﹑岩溶角砾岩等标志.     

基于颜色和标志边缘特征的交通标志检测

首先利用禁令标志明显的红色边界和白色区域分别并行地提取可能的交通标志颜色,然后对其两者融合,其目的是减少漏检率;融合后的影像通过Canny算子提取其边界,再根据边界的圆形度参数判断是否为圆形区域.实验结果显示,本算法能够很好地检测和定位禁令标志.     

远离喧嚣完美生活

屋主精心设计自己一家三口的安乐窝,为求完美,精挑细选家里每道门户每盏灯.原来在他背后有一套追求完美的生活态度.     

雨花石研究新进展

南京雨花石千姿百态、颜色五彩缤纷、花纹浑然天成,驰名中外。美丽的玛瑙质雨花石珍品,被誉为“中华一绝”、“华夏一奇”、“天下第一美石”等。     

Environmental geohydrochemistry and health of the high altitude population in Ladakh

Background： Radiographic signs of Pneumoconiosis found in farming Ladakhi despite absences of mines and industries were believed to be due to exposure to frequent dust storms and domestic fire pollutions. Seasonal Koilonychia （spoon nail） occurring predominantly in farming women in absences of iron deficiency anaemia was thought to arise from exposure to water made alkaline by weathering of hornblende minerals. The relation of these health conditions to environmental geohydrochemistry is postulated as the source of irrigation water in the affected population originates from glaciers in trans-Himalaya range of sedimentary geology and steep landscape favouring flushing of silica/silicate containing silts. Methods and results： Survey in two central Ladakh villages revealed radiographic evidence of silicosis in all middle aged women and half in middle aged men. In a large-scale study of 3105 subjects aged over 30 years from three villages; 101 （22.5%） of the 449 radiographed showed signs of pneumoconiosis （ILO 1980 criteria） including eggshell calcification of hilar gland and progressive massive fibrosis. Indoor dust analyzed using Philips 400T electron microscope with energy dispersive analysis system attached showed SiO2 levels upto 53.27% with particle size of 0.5 to 5.0 microns and the concentration during cooking period in the worst affected area was 7.495 mg/m^3. Microscopy and histopathology from the subject was characteristic of pneumoconiosis. Analysis of the inorganic dust in the lung showed 40.2% muscovite, 37.3% quartz with the extracted dust wt 147.9 mg/gm of dry tissue. Prevalence of chronic cough with chronic phlegm and percentage of villagers with FEV1/FVC ratio of less than 65% rose with age. Of 70 subjects studied 19 women and 2 men had Koilonychia with incidence being highest in summer. Absence of seasonal Koilonychia in villages fed by water derived from northern mountain range glaciers with mainly igneous geology supports our hypothesis.     

Natural siliceous dust and human health： Pathways, toxicity, and impact

Fine atmospheric dust includes mineral particles and aggregates, fibrous minerals and fibrous organic material. Generation, dislodgement and transport （deflation） of natural dust with the finer （〈4 microns） components suspended as silt-size aggregates, is widespread in and adjacent to the world＇s drylands, as well as deriving from volcanic vents. Silica is a highly fibrogenic agent in lung tissue. Long-term inhaling of siliceous dusts can lead to a number of fibrotic lung diseases, including natural （non-occupational） pneumoconioses （notably silicosis, but including asbestosis and others）. Different polymorphs of silica show different levels of toxicity in interaction with lung tissue. Particles with highly active surfaces may release radicals, causing cell damage. Some types of inhaled particulates are degraded by macrophages, but many are highly resistant and persist in the lungs, some stimulating fibroblastic cells to deposit collagen. Silicosis is an inflammation of the lung commonly caused by silicate mineral particles, leading to fibrosis. Three types are recognized： nodular pulmonary fibrosis （simple or chronic silicosis）, acute silicosis, and accelerated silicosis. Generally, finer particulates have greater oxidative capacity than the coarser fractions. They contain more reactive oxygen species, their greater bioreactivity making them more toxic to pulmonary tissue. Nevertheless, inhalation of large dust particles （〉 10μm） may constitute a health risk if the mineralogy is toxic, regardless of where the grains lodge in the respiratory system. Dust may absorb harmful gases, disease-generating bacteria and carcinogenic hydrocarbon compounds. Silica-related respiratory disease may also an exacerbate cardiac problem, and epidemiology suggests a link with tuberculosis. Quantification of dust loading and exposure requires study of spatial and temporal patterns, supported by meteorological analysis, airflow modeling and satellite-borne imagery. Some acute, short-term health impacts have been assessed using atmospheric and health records both before and after a dust storm or by comparison of populations within and outside such events. Analysis of the size, shape, mineralogy and geochemistry of ambient dust particulates provides information on natural dust sources, dust concentrations, and potential particulate toxicity, as well as providing a datum for assessment of human exposure levels.