Sea Snakes: An Unusual Salt Gland under the Tongue

The posterior sublingual gland of sea snakes is a salt gland. It secretes a fluid surpassing seawater in sodium chloride concentration. The gland lies on the ventrolateral surfaces of the tongue sheath and empties through multiple ducts into the sheath. Fluid is expelled from the sheath when the tongue is extended. For freshly captured Pelamis, the plasma concentrations of sodium, chloride, and potassium were 210, 167, and 8 millimoles per liter, respectively. Injections of sodium chloride led to a rise in its concentration in the plasma and to an increase in the rate and concentration of fluid secreted by the sublingual gland. The ultrastructure of this gland is similar to that of other reptilian salt glands. However, the gland is not homologous with any other salt gland. The sublingual gland in Pelamis is larger than that in Laticauda, and the rate of electrolyte excretion from the larger gland is greater.     

Diploid-Triploid Mosaicism: An Unusual Phenomenon in Side-Necked Turtles (Platemys platycephala)

Diploid and diploid-triploid mosaic individuals of Platemys platycephala were found in natural populations. In mosaic specimens, the blood, spleen, liver, and testis contained both diploid and triploid cells. The ratio of triploid to diploid cells was more variable among individuals than among somatic tissues within an individual. Only diploid cells underwent meiosis in males; haploid gametes were produced. There appears to be geographic variation for mosaicism in that only diploids were found in Bolivia, whereas diploids and diploid-triploid mosaics occured in Surinam.     

一次罕见的秋季连阴雨天气过程成因分析

2007年秋季连阴雨是山东省由观测记录以来发生的历史时间最长、危害程度最大的一次秋季连阴雨过程。从大气环流背景、物理量特征、热带气旋活动等方面,对其成因进行了详细的分析。结果表明,这次连阴雨是在亚欧大尺度环流形势由纬向型向径向型转变的过程中发生的,是一次长波调整的过程。连阴雨期间乌拉尔山高压脊和西太平洋副热带高压较常年同期异常偏北、偏强,长时间稳定维持,同时副热带高压南侧东风带内热带气旋活动频繁,亚洲中纬度地区多短波槽活动,引导西西伯利亚冷空气东移南下,与孟加拉湾和沿副高外围北上的暖湿气流在黄河下游交绥,造成了山东持久的连阴雨天气。     

Aquatic Respiration: An Unusual Strategy in the Hellbender Cryptobranchus alleganiensis alleganiensis (Daudin)

Separate and simultaneous determinations of aerial and aquatic gas exchange in the giant salamander, Cryptobranchus alleganiensis alleganiensis (Daudin) were made at 5 degrees , 15 degrees , and 25 degrees C. The aquatic respiration of this animal accounts for over 90 percent of the total volume of oxygen consumed and 97 percent of the total volume of carbon dioxide released at all temperatures. The lungs of these individuals are large transparent sacs which are poor respiratory organs; the lungs probably function more as hydrostatic structures than as gas exchangers. This animal is the largest aquatic vertebrate that lacks gills and yet utilizes almost exclusively an aquatic mode of respiration. Specialized cutaneous modifications, a unique body form, and a peculiar behavioral mechanism are of considerable adaptative significance, and confer to the skin the effectiveness of a veritable "gill."     

苏州地区湖羊资源的保护与开发利用

湖羊是世界著名的多羔绵羊品种之一,原产于江浙两省交界的太湖流域,苏州是主产区之一。湖羊具有性成熟早、产羔多、繁殖力高、四季发情、耐湿热、耐粗饲、宜圈养等优良性状;所产羔皮,皮板轻薄,呈波浪状花案,扑而不散;肉质细嫩鲜美、膻味少,既适合于我国南方饲养,又可以在北方地     

Pyrite Group: An Unusual Member: Cu0.60Ni0.14Co0.03Fe0.23S2

An investigation of villamaninite from the type locality indicates that former analyses were of aggregates rather than of individual minerals. A redefinition embraces a larger range of solid solution, the end-member of which has the highest content of copper so far attributed to a member of the pyrite family.     

江汉平原湖积型涝渍地土壤物理环境质量评价

对江汉平原湖积型涝渍地域土壤硬度、耕层厚度、结构性、容重、质地等物理环境质量进行了监测。结果表明：涝渍地土壤深厚,有效土层均在1．0m以上;质地以中壤为主,约占83％,过砂过粘的土壤较少;耕层土壤厚度过浅,机耕可有效增加耕层厚度;耕层土壤硬度5～7kg／cm^2;犁底层硬度能满足大型机械作业,1m以内无硬盘层出现;土壤障碍层次为浅位中、厚层夹砂或夹粘层;地下水位过高,小于60cm的占39％,局部地区比例更大;结构性和渗透性不良;三相比例失调,水多气少,固相率偏高。多项物理指标需要改良。     

湘南湖相软质沉积岩工程性质研究

通过试验结果分析,讨论了湘南湖相软质沉积岩中粘土岩类岩石及碎屑岩类岩石的路用工程性质。     

Unusual topogenic sequence directs prion protein biogenesis

Biosynthetic studies of the prion protein (PrP) have shown that two forms of different topology can be generated from the same pool of nascent chains in cell-free translation systems supplemented with microsomal membranes. A transmembrane form is the predominant product generated in wheat germ (WG) extracts, whereas a completely translocated (secretory) form is the major product synthesized in rabbit reticulocyte lysates (RRL). An unusual topogenic sequence within PrP is now shown to direct this system-dependent difference. The actions of this topogenic sequence were independent of on-going translation and could be conferred to heterologous proteins by the engineering of a discrete set of codons. System-dependent topology conferred by addition of RRL to WG translation products suggests that this sequence interacts with one or more cytosolic factors.     

Unusual retinal cells in the dolphin eye

By comparison to the cellular constituents of the retinas of certain other diving mammals, the elements of the dolphin retina include an unusually large number of specialized cells. Both cone and rod receptors may be identified. An unusual amacrine cell may be seen which produces a process that spans the cells between the inner plexiform and outer plexiform layers. Most unusual is a layer of giant ganglion cells which appears to serve most of the central retina. The giant ganglion cells support giant dendrites and optic nerve fibers which range up to 8 micrometers in diameter.