Chlorinated hydrocarbons and eggshell changes in raptorial and fish-eating birds

Catastrophic declines of three raptorial species in the United States have been accompanied by decreases in eggshell thickness that began in 1947, have amounted to 19 percent or more, and were identical to phenomena reported in Britain. In 1967, shell thickness in herring gull eggs from five states decreased with increases in chlorinated hydrocarbon residues.     

日粮镁对蛋壳中矿物元素含量及蛋壳质量的影响

研究日粮镁对蛋壳中矿物元素含量及蛋壳质量的影响。采用了在基础日粮中含镁2 258 mg/kg,外加镁3 742 mg/kg(添加氧化镁)饲予20周龄海兰白蛋鸡的方法;结果表明,过量镁对蛋壳中的钾、钠、钙、镁、磷、锌、铁的含量影响差异不显著(P>0.05),对蛋壳强度、蛋壳厚度、蛋型指数的影响差异不显著(P>0.05),使软破蛋率升高。通过电镜观察可以看出,过量镁使蛋壳内表面乳头大小不均,结合不紧密,乳头间空隙较大,外表面有较宽的裂纹,出现了裂缝,这些裂缝很可能成为以后破裂的始点。     

Photooxidation of DDT and DDE

The pesticide DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane] and its metabolite DDE [ 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene] can be photoOxidized in methanol. Photolytic generation of free radicals that may abstract hydrogen from solvent, react with oxygen, or abstract hydrogen from unreacted substrate occurs. Further decomposition of short-lived intermediates yields many compounds. Oxidation products include benzoic acids, aromatic ketones, and chlorinated phenols. The DDE also undergoes photocyclization to give dichlorofluorene derivatives.     

Alaskan thermokarst terrain and possible martian analog

A first-order analog to martian fretted terrain has been recognized on enhanced, ERTS-1 (Earth Resources Technology Satellite) imagery of Alaskan Arctic thermokarst terrain. The Alaskan analog displays flat-floored valleys and intervalley uplands characteristic of fretted terrain. The thermokarst terrain has formed in a manner similar to one of the processes postulated for the development of the martian fretted terrain.     

影响蛋壳质量的因素与应对措施

在鸡舍里，我们常常可以看到有的鸡蛋外观质地不均匀，有明显的痕迹，如沙皮蛋、皱纹蛋、薄壳蛋等，稍碰便破。这些蛋的商品价值比较低，不容易储存和运输，也不能作为种蛋使用。这种蛋产生的原因主要有以下几个方面：１饲料中钙的含量不足钙是形成蛋壳的重要元素，产蛋鸡需要大量的钙以维持产蛋需求。据报导，一个鸡蛋所含钙约为２ｇ，一只蛋鸡一天需要摄入钙４ｇ左右。饲料中如果缺钙就会产下薄壳蛋、软壳蛋等。一只鸡每天采食１１０～１２５ｇ饲料，而鸡对饲料中钙的利用率约为６０％。所以产蛋鸡的饲料中钙含量应达到３.５％～３．８％…     

DDE: its presence in peregrine eggs in 1948

DDE has been eluted from the dried membranes of peregrine egg-shells collected in California from 1948 to 1950, and identified by gas-liquid chromatography.     

鸡蛋膜的生物吸附作用研究新进展

由于人类社会的工业发展和重大安全事故,重金属离子与有机污染物不断向环境排放,造成土壤和水体的污染日益严重。鸡蛋膜(eggshell membrane,ESM)作为一个独特的富含二硫键的天然生物吸附材料在环境水污染处理中应用研究不断拓展。综述近年来鸡蛋膜及改性材料对重金属离子及有机污染物的吸附研究进展,为充分利用廉价吸附材料鸡蛋膜研究提供参考。     

鸭蛋壳颜色定量测定与统计学分析

以缙云麻鸭所产鸭蛋为素材,采用ECR测色仪对其4种类型鸭蛋的蛋壳颜色进行定量测定,每种类型测50个蛋,每个蛋测定3个点.结果表明:白壳、浅青壳、青壳和深青壳4组蛋的反射系数均值各组间差异极显著(P0.01);利用反射系数与蛋壳颜色的回归分析得出划分青壳蛋颜色层次的量化区间,即白壳蛋80.64~84.42,浅青壳蛋77.74~80.64,青壳蛋74.85~77.74,深青壳蛋64.69~74.95;对各测定点的测定值与均值的相关分析和主成分分析表明,中端为蛋壳颜色的最佳测定点,其准确性可达到0.8934;蛋壳反射系数与时间的回归分析表明,不同时间的反射系数测定值间差异不显著(P0.05).     

Carbonic anhydrase interaction with DDT, DDE, and dieldrin

The active site of various carbonic anhydrases is not blocked by DDT. DDE, or dieldrin. Impairment of catalytic efficiency can only be documented in opalescent test solutions in which the insecticides are present in excess of their solubility limit. These slowly forming precipitates occlude enzyme from solution and furnish a physical explanation of the supposed inhibition. The amounts occluded depend, among other things, on the conformational and topographical characteristics of the particular carbonic anhydrase molecules.     

鸡蛋壳膜分离装置设计及试验研究

鸡蛋壳蛋膜中富含的胶原蛋白、角蛋白及高分子化合物是医药、化妆品及生物工程中重要原材料,蛋壳与蛋膜分离具有一定应用价值。试验设计制造一种机械搅拌式鸡蛋壳膜分离装置,分离鸡蛋壳与附在其内壁上膜,分析分离容器内搅拌流场和鸡蛋壳膜分离最佳因素参数组合。通过仿真及试验,当分离容器直径400 mm,内壁均布四个宽度40 mm挡板时,桨叶旋转直径为200 mm,两层桨层间距≤200 mm,下层桨离底面距离≤100mm,转速≥150 r·min~(-1)时,产生较好整体轴向流,利于颗粒悬浮。以膜回收率最大化为原则优化分析,发现当搅拌转速168~200 r·min~(-1),搅拌时间8.5~15 min,料液比120,温度20℃时,膜回收率达68%以上,分离效果较好。该装置为研究废弃鸡蛋壳回收利用提供解决方案,为机械式搅拌分离各种禽类壳膜研究提供参考。     

Cyclic variation and solar forcing of Holocene climate in the Alaskan subarctic

High-resolution analyses of lake sediment from southwestern Alaska reveal cyclic variations in climate and ecosystems during the Holocene. These variations occurred with periodicities similar to those of solar activity and appear to be coherent with time series of the cosmogenic nuclides 14C and 10Be as well as North Atlantic drift ice. Our results imply that small variations in solar irradiance induced pronounced cyclic changes in northern high-latitude environments. They also provide evidence that centennial-scale shifts in the Holocene climate were similar between the subpolar regions of the North Atlantic and North Pacific, possibly because of Sun-ocean-climate linkages.     

Lack of abnormal hemoglobins in Alaskan Eskimos,Indians, and Aleuts

In an examination of the blood of 708 Eskimos, 200 Aleuts, and 44 Indians in Alaska for abnormal types of hemoglobin, only normal hemoglobin A was detected. It may be concluded that abnormal hemoglobins in these races are rare if they occur at all.     

Insecticide content of diet and body fat of Alaskan natives

A study was made of the DDT and DDE content of the diet and body fat of native Alaskans who lived in isolated, primitive areas and had minimal contact with insecticides. No DDT or DDE was detected in any of the native Alaskan foods analyzed with the exception of two white owls, both of which contained low levels of DDE. Eskimos store considerably less DDT and DDE in their body fat than the general population in the United States. These low dietary levels and the resultant low levels in body fat are consistent with previously published data on the relationship between intake and storage of DDT.     

Dating pleistocene archeological sites by protein diagenesis in ostrich eggshell

Eggshells of the African ostrich (Struthio camelus), ubiquitous in archeological sites in Africa, have been shown by laboratory simulation experiments to retain their indigenous organic matrix residues during diagenesis far better than any other calcified tissue yet studied. The rate of L-isoleucine epimerization to D-alloisoleucine follows reversible first-order kinetics and has been calibrated for local temperature effects and used to estimate the age range of stratified archeological sites. Age estimates are consistent with radiocarbon dates from several stratified archeological sites. With adequate calibration, this technique can provide accurate ages to within 10 to 15 percent for strata deposited within the last 200,000 years in the tropics and the last 1,000,000 years in colder regions such as China.     

Deposition of DDE and polychlorinated biphenyls in dated sediments of the Santa Barbara basin

Analysis of dated oceanic sediments from the Santa Barbara Basin of the Southern California Bight has shown that deposition of polychlorinated biphenyls (PCB) began about 1945 and that DDE [1,1-dichloro-2-2-bis(p-chloro-phenyl)ethylene] first appeared in sediments deposited about 1952. Concentrations of both show a progressive increase through 1967; estimated deposition rates (in grams per square meter per year) in 1967 of DDE and PCB were 1.9 x 10(-4) and 1.2 x 10(-4), respectively.     

融合梯度幅值和置信度的鸡蛋裂纹图像检测

提出一种融合梯度幅值和置信度的鸡蛋裂纹检测新方法.采集褐壳鸡蛋的裂纹图像,运用提及边缘检测算法获取感兴趣区域图像,采用最大边界算法挑选边界轮廓,融合二者获取裂纹区域图像.对3种典型鸡蛋裂纹图像进行边缘检测新方法与传统边缘检测算子(Log算子、Sobel算子及Canny算子)对比试验,结果表明:融合梯度幅值和置信度的鸡蛋裂纹检测新方法能够克服固定阈值适应性较差的缺陷,提高检测准确率,在消除噪声、增强弱边缘信息方面优于传统边缘检测算子.     

基于Adaboosting_SVM算法的多特征蛋壳裂纹识别

以无裂纹蛋和裂纹蛋为测试对象,采用机器视觉技术和支持向量机等技术手段,分析无裂纹蛋和裂纹蛋在图像上的差异,提取特征参数,实现蛋壳裂纹的自动识别;针对蛋壳表面的亮斑,对预处理后的图像运行消除亮斑算法并进行区域标记。在此基础上,从5个不同视角提取13个能够表征无裂纹蛋和裂纹蛋的特征参数,分别是图像标记区域参数(区域标记数和标记点数)、几何特征参数(长轴和短轴)、基于Freeman链码的形状参数(形状数)、纹理特征参数(均值、标准偏差、平滑度、三阶矩、一致性、熵)和频谱特性参数(最大幅值和最大相位)。采用Adaboosting算子对上述特征参数进行优化,突出影响因子较大的参数组合,作为SVM的输入向量,建立蛋壳裂纹的识别模型。结果表明:该方法对蛋壳表面的亮斑、微小裂纹及普通裂纹均具有识别能力,模型正确率达97.5%,符合蛋品企业对蛋壳裂纹检测的精度要求。     

Cesium-137 body burdens in Alaskan Eskimos during the summer of 1965

Cesium-137 body burdens of Anaktuvuk Pass, Alaska, residents during the summer of 1965 were about 30 percent less than during 1964. Lower amounts of cesium-137 in the people reflected a similar decrease of this isotope in caribou flesh, which serves as the principal food of the natives.