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1.
Earliest middle Cambrian rocks in the Franconian Forest, formerly known as the ‘Galgenberg Formation’, include a moderately diverse fauna with a characteristic West Gondwanan, Atlas-type trilobite assemblage with often surprisingly well-preserved specimens. The hitherto inadequately characterised and poorly described assemblage includes Kingaspidoides frankenwaldensis, K. sp. aff. usitata, K. alberti sp. nov., K. meieri sp. nov., K.? sp. A, Ornamentaspis cf. crassilimbata, Latikingaspis sp. aff. alatus, Enixus sp. aff. juvenis, Acadoparadoxides sp. A, Parasolenopleura wurmi sp. nov., Parasolenopleura parabolica sp. nov. and Acanthomicmacca franconica Geyer, 2016. In addition to precise documentation of the species’ morphology and ontogenetic development, this study exemplifies allometric developments during the ontogeny of ellipsocephaloid and early solenopleurid trilobites, particularly Kingaspidoides and Parasolenopleura, and effects of deformation and distortion caused by diagenesis and tectonics. It further discusses the aspects of the trilobites’ ecology and taphonomy, and it characterises generic differences within the Kingaspis clade, particularly of Kingaspidoides, Latikingaspis and Ornamentaspis.  相似文献   

2.
Abstract The result of a study on the internal structures during the development of sensilium and anal segment from first instar larva to adult of Leptopsylla segnis (Schinherr 1811), Monopsyllus anisus (Rothschild 1907) and Ctenocephalides felis felis (Bouche 1835) is reported and summarized as follows: (1) The development of the sensilium and anal segment of these fleas is essentially the same. (2) The first sensilium rudiment appears in the early third instar larva on the anterior one-second part of the tergite of the tenth abdominal segment, and in prepupa the eleventh abdominal segment which is composed of the dorsal and ventral anal lobes is formed, and in the pupa the sensilium and its frame are fully developed. (3) The differenced of opinions on the terminal segments of the flea are discussed.  相似文献   

3.
In Rex vs. Arnold (1724) it was held that to avail himself of the defense of insanity “a man must be totally deprived of his understanding and memory, so as not to know what he is doing, no more than an infant, a brute, or a wild beast.” Although there has been some modification of this formula in most jurisdictions, the courts still operate under the McNaghten Rule (1843) which is no more logical and actually is more difficult to apply. That such a situation exists in 1956 is a reflection on the indifference of society—and particularly the courts which it elects—as well as on the failure of modern psychiatry to communicate its viewpoint to society. If we are to correct the sad formulae of the “right and wrong” and “policeman at the elbow” tests, we must have more study and better methods of communication in this area.A similar state of confusion exists in the methods of commitment of mentally ill people to psychiatric hospitals. The methods prescribed by law are archaic and cruel—and again reflect the failure of modern psychiatry to communicate its understanding to the legislatures and courts.There are many other areas of conflict between law (which looks to the past for its insights) and psychiatry (which seeks for its concepts in the current scientific advances).  相似文献   

4.
印度瓜野螟种群的增长力及其密度制约   总被引:1,自引:0,他引:1  
王金福 《动物学研究》1989,10(3):233-239
在养虫室内群体饲养条件下,对印度瓜野螟种群动态的测定结果表明:第二代和第三代的种群内禀增长力(rm)分别为0.0792和0.0487,它们的累计产卵率随时间而表现出逻辑斯蒂曲线变化。在相同的生活和取食空间内,幼虫的发育速率和存活率随种群密度的增长而下降;每对成虫的每天产卵量随成虫密度的增加而递减,单对成虫密度下的产卵率比17对成虫密度下的产卵率高达18倍左右。  相似文献   

5.
W. H. Thorpe 《Ibis》1955,97(2):247-251
The 'Bird Fancyer's Delight' (1717) is considered in the light of modern knowledge of the process of song-learning in birds. Some conclusions (if Baron von Pernau (1716) as to song imitation are also discussed. A new example of the ability of the Chaffinch to incorporate song phrases from other species into its sub-song is given. It is suggested that there is an important difference between its true song and its sub-song in this respect and that this difference may throw light on the ability of some other finches to learn alien songs.  相似文献   

6.
Previous reports have indicated that calcium is necessary to support active sodium transport by the toad bladder, and may be required as well in the action of vasopressin on both toad bladder and frog skin. The structure and function of the toad bladder has been studied in the absence of calcium, and a reinterpretation of the previous findings now appears possible. When calcium is withdrawn from the bathing medium, epithelial cells detach from one another and eventually from their supporting tissue. The short-circuit current (the conventional means of determining active sodium transport) falls to zero, and vasopressin fails to exert its usual effect on short-circuit current and water permeability. However, employing an indirect method for the estimation of sodium transport (oxygen consumption), it is possible to show that vasopressin exerts its usual effect on Qoo2 when sodium is present in the bathing medium. Hence, it appears that the epithelial cells maintain active sodium transport when calcium is rigorously excluded from the bathing medium, and continue to respond to vasopressin. The failure of conventional techniques to show this can be attributed to the structural alterations in the epithelial layer in the absence of calcium. These findings may provide a model for the physiologic action of calcium in epithelia such as the renal tubule.  相似文献   

7.
Formation and regeneration of the genital papilla in the sea urchin, Hemicentrotus pulcherrimus were studied to find out what factor(s) control expression of the secondary sexual characters in the papilla. Surgical removal of various regions of the genital organ and the blood vessels was performed separately or in various combinations. The proximal part of the genital duct or its rudiment (D2 region) plays an essential role in the formation or regeneration of the papilla, and in the establishment of its sexual characters as well, i.e., if the D2 region is removed, papilla formation or regeneration is completely suppressed; when the D2 region is left uninjured, the papilla develops and displays the sexual characters even in the absence of the gonad, the distal part of the duct, a blood supply to the D2 region or all three of them combined. It can be concluded that the proximal part of the genital duct carries the factor(s) for determination and expression of the secondary sexual characters in the genital papilla. Discussion has been made about what factor(s) can be considered to reside within the cells of the D2 region of the duct.  相似文献   

8.
栓菌属和它的亲缘属属界划分的研究   总被引:1,自引:0,他引:1  
栓菌属(Trametes) 自Fries(1835)建立迄今已有近150年的历史。Fries(1835),Patouillard(1900),Kotlaba & Pouzar(1957),的工作代表了对本属研究的三个比较重要的发展阶段。许多分类学家都认为栓菌属是多孔菌科(Polyporaceae,Basidiomycetes)中最混乱、最不易划清属间界限的一个类群。研究清楚这一属和它的亲缘属的属界以及它们之间的相互关系是研究多孔菌科分类中十分重要的课题。作者多年来在研究这一类群的过程中,常常遇到属界不清,它们之间的相互关系也不易搞清楚等问题。从文献中可以看出,有的种类似乎可以随便地从一个属转移到另一个属,正确与否不易确定。因此,感到搞清楚本属的属界是十分重要的。作者即是在这一情况下进行这一课题研究的。首先搞清楚栓菌属的发展历史,各分类学家对它的不同概念,最后提出作者对本属的概念。然后再搞清楚各亲缘属的属界与其相互关系。凡是作者承认的属都提出自己的概念。  相似文献   

9.
四川侏罗纪三列齿类头后骨骼   总被引:1,自引:1,他引:0  
本文记述了最晚期的三列齿类——似卞氏兽 (Bienotheroides) 的头后骨骼,并和其他三列齿类以及原始哺乳动物作了对比.肩胛骨上雏型岗上窝的出现,证明三列齿类与原始哺乳类的关系要比以往想象的更为密切.  相似文献   

10.
The principal conclusion of this investigation is that the inhibitory effect of plasma or serum on hemolysis by saponin and lysins of the same type is similar in nature to the inhibitory effects of certain sugars and electrolytes, which again are similar to the acceleratory effects produced by indol, benzene, and other substances already studied. All these effects, both inhibitory and acceleratory, are the result of reactions between the inhibitors or accelerators and those components of the red cell membrane which are broken down by lysins. The inhibitory effect of plasma on saponin hemolysis has a number of properties in common with the inhibition produced by sugars and electrolytes and with accelerations in general. (a) The temperature coefficient is small and negative. (b) The extent of the inhibition depends on the type of red cell used in the hemolytic system. (c) The most satisfactory measure of the extent of the inhibition, the constant R, is a function of the concentration of lysin in the system, and (d) R is a linear function of the quantity of inhibitor present. It is also shown that the inhibitory effect of plasma, and serum is not entirely dependent on its protein content. The process underlying the phenomenon of lysis and its acceleration or inhibition seems to be one in which the lysin reacts with a component or components of the cell membrane in such a way as to break down its semipermeability to hemoglobin, and in which the accelerator or inhibitor also reacts with the same component in such a way as to increase or decrease the effectiveness of the lysin in producing breakdown. The membrane is considered as being an ultrastructure made up of small areas or spots of varying degrees of resistance to breakdown, the resistances being distributed according to a negatively skew type of frequency curve, and the process of lysis seems to begin with the least resistant spots breaking down first. These spots may be arranged in some regular spatial pattern, and the membrane has also to be regarded as possessing spots of varying rigidity of form. The accelerator or inhibitor changes the resistance of every reactive spot in the ultrastructure by a factor R, which suggests that acceleration and inhibition are results of some over-all effect, such as that of changing the extent to which lysin is concentrated at the surface or partitioned between the material of the membrane and the surrounding fluid. Some kind of combination between the accelerator or inhibitor and the material of the ultrastructure is presumably involved; at first the combination seems to be a loose one and partly reversible, but later some of the loose links are replaced by more permanent combinations involving the same types of bond as are broken down by the lysins themselves.  相似文献   

11.
Abstract:  Eshanosaurus deguchiianus is based on a single left dentary from the Lower Lufeng Formation (Lower Jurassic) of Yunnan Province, China. It was originally identified as the earliest known member of Therizinosauroidea (Theropoda: Coelurosauria), a conclusion that results in a significant downward range extension for this clade (>65 million years) and for many other major lineages within Coelurosauria. However, this interpretation has been questioned and several authors have proposed that the anatomical features used to refer Eshanosaurus to Therizinosauroidea are more consistent with attribution to a basal sauropodomorph dinosaur. Detailed consideration of the holotype specimen suggests that several features of the dentary and dentition exclude Eshanosaurus from Sauropodomorpha and support its inclusion within Therizinosauroidea. If accepted as an Early Jurassic coelurosaur, Eshanosaurus has important implications for understanding the timing and tempo of early theropod diversification. Moreover, its provenance also suggests that substantial portions of the coelurosaur fossil record may be missing or unsampled. However, the Early Jurassic age of Eshanosaurus requires confirmation if this taxon is to be fully incorporated into broader evolutionary studies.  相似文献   

12.
literature pertaining to the development and regulation of dormancy in the buds of woody species is reviewed and interpreted as follows. Morphological observations, the effects of environmental factors, and other evidence support the concept that bud dormancy involves a cycle of 3 separate phases of development. Beginning at the developmental pattern of spring, the 3 phases are: (1) dormancy development leading to the dormant state; (2) release from dormancy leading to the non-dormant state; and (3) the initiation of spring burst leading again to spring development. The regulation of dormancy is, therefore, discussed in terms of the regulation of development of the apex within each phase and the regulation of transitions between phases. The principal existing theory of dormancy regulation implies that dormancy consists, in total, of merely the inhibition of spring development, and that regulation involves first the accumulation of an inhibitor then its disappearance. The conceptual basis of this inhibitor theory is argued to be inadequate as is the experimental evidence for the existence of a specific inhibitor and for a correlation between its concentration and dormancy induction or release. There is little direct evidence on the mechanism of the regulation of bud development within any developmental phase. Circumstantial evidence suggests the developmental patterns arise from chemical patterns resulting from the interactions of classes of growth regulator such as auxin, kinin, and gibberellin. Some evidence exists concerning the regulation of the transitions between the phases of dormancy. A substance has recently been detected which may be a hormone regulating the initiation of dormancy development. The production of this substance may be photoperiodically determined. A role for gibberellins in the regulation of dormancy release has been postulated.  相似文献   

13.
姜黄色素增溶的研究   总被引:2,自引:0,他引:2  
本研究以脂溶性姜黄色素为材料,探讨其增溶后的水溶性、耐光性、耐加热性、安全性及增溶费用.结果表明,增溶后的姜黄色素不仅水溶性好,而且色泽鲜艳、着色力强,耐光性、耐加热性也较好;增溶后的姜黄色素安全无毒;增溶费用低.从而为工业化生产水溶性姜黄色素提供了理论依据.  相似文献   

14.
大肠杆菌抗氟乙酸变株的选育及应用   总被引:6,自引:1,他引:5  
In the cultivation of gene engineered strain of Escherichia coli on glucose medium, excretion and accumulation of acetic acid inhibit not only cell growth but also the the expression of heterologous protein. It is obvious that the desirable host strain maintaining acetate at a low level is one of the approaches to increase the production of recombinant protein. The present article deals with the selection of mutants of E.coli DP19, DP8, which grow on the medium containing pyruvate as the sole carbon…  相似文献   

15.
1. When myosin is exposed to a typical denaturing agent (acid) it becomes insoluble and its SH groups are activated. 2. The same number of active SH groups is found in the soluble myosin of resting muscle as in the insoluble myosin of muscle in rigor. No activation of SH groups accompanies the formation of insoluble protein in rigor. 3. When the insoluble myosin of muscle in rigor is treated with a denaturing agent its SH groups are activated. 4. Protein coagulation as brought about by denaturing agents (heat, acid, alkali, alcohol, urea, salicylate, surface forces, ultraviolet light) is a distinctly different change from the coagulation of myosin brought about by the unknown agent in muscle.  相似文献   

16.
Black rhinoceroses were hunted on foot, from a vehicle, or from a helicopter throughout their range of habitats. Animals weighing 370–1,260 kg could be handled an average of 13 min after darting with a mixture of etorphine (1.9 μg/kg) and acepromazine (19 μg/kg). Cases of respiratory depression at this dosage were reversed soon after immobilisation by the intravenous injection of cyprenorphine (1.0 μg/kg). The captured animal was transported to camp, lashed on its side to a sledge, for periods of up to 515 min without mishap. A rhinoceros that was unloaded 180 min after darting rose to its feet and tried to push its way through the corner of the pen until antidote was administered at 215 min. This action was not observed in animals that received a total dose of 3.4 μg/kg of cyprenorphine before being unloaded 90–413 min after darting. The addition of hyoscine (at doses as low as 18 μg/kg) to etorphine and acepromazine improved the tractability of rhinoceroses that were only partially immobilised. However, sometimes at this dosage and always at doses above 35 μg/kg, hyoscine prolonged the ‘pushing’ phase for 175–410 min after darting despite the administration of cyprenorphine (4.0 μg/kg). There were no mortalities due to drug action in the series of 59 healthy rhinoceroses that were dart-immobilised, but there were two deaths due to mishandling and one caused by subsequent mismanagement.  相似文献   

17.
克鲁斯假丝酵母及其近似种的脉冲电泳核型分析   总被引:6,自引:0,他引:6  
用钳位均匀电场脉冲电泳(CHEF)系统分析了克鲁斯假丝酵母(Candida krusei),郎比可假丝酵母(C. lambica)和粗状假丝酵母(C. valiad)的模式菌株的电泳核型,发现这三种表型相似的假丝酵母却具有互不相同的染色体DNA分子带型,为其分类学研究提供了可靠的鉴别依据。在常规分类学研究的基础上,测定了AS 2.75(原定种名为(C. incospicua),AS2.1182(原定种名为 C. lambica)和AS 2.1772(未定种)等三株假丝酵母的G+C含量和脉冲电泳核型。通过对已报道的C. inconspicu的G+C含量及上述三种假丝酵母模式菌株的脉冲电泳核型的比较分析证明,AS 2.75和AS 2.1772为粗状假丝酵母(C. valida),AS 2.1182为克鲁斯假丝酵母(C. krusei)。  相似文献   

18.
白暨豚的舌   总被引:2,自引:0,他引:2  
在现代生存的四类淡水豚中,恒河豚(Platanista gangetica)和拉河豚(Pontoporia blain-villei)的舌已有详文报道(Arvy和Pilleri,1970;Yamasaki等,1976a)。亚河豚(Iniageoffrend)的舌也在Yamasaki的文章中作为和上述二种淡水豚舌的比较而述及。白暨豚(Liptes vexillifer)的舌除陈宜瑜等(1975)曾提及外,迄今未有其他报道。鉴此,作者对白暨豚的舌作了解剖学和组织学的观察,现将研究结果报告如下: 白暨豚舌的标本取自幼体、亚成体、成体和老年个体等七头个体。为了比较,还收集了亚河豚、其它海豚类和陆生哺乳类的舌。用10%甲醛固定保存,各项量度根据固定标本测量。白暨豚舌的外形描述以NNC 7909号标本为主,以其它个体的观察为辅。其组  相似文献   

19.
CO_2失汇与北半球中高纬度陆地生态系统的碳汇   总被引:13,自引:0,他引:13       下载免费PDF全文
化石燃料消耗及热带林破坏导致约 7.0 Pg C· a- 1 (1Pg=10 9t)的 CO2 向大气排放 ,其中 3.0~ 3.4Pg C·a- 1 的 CO2 被用于大气 CO2 浓度的升高 ,约 2 .0 Pg C· a- 1 的 CO2 被海洋吸收 ,而陆地生物圈被认为是 CO2 净吸收与净排放基本达到平衡。因此 ,在人工源 CO2 中 ,尚有 1.6~ 2 .0 Pg C· a- 1的 CO2 去向不明。这就是著名的 CO2 失汇之谜。大气成分监测、CO2 通量测定以及模型模拟等方面的研究都表明 ,北半球陆地生态系统是一个重要的碳汇 ,但其值存在很大的不确定性 ,且具有较大的时空变化。全球温暖化、CO2 施肥效应 ,氮和磷沉降的增加以及人工植被的扩大是形成碳汇的主要因素。为减少碳汇估计值的不确定性 ,除加强长期定位监测、改良现有估测模型外 ,重视研究土壤圈在碳循环中的作用至关重要  相似文献   

20.
1. The cross-striation in the indirect flight myofibrils of Calliphora has been studied by phase contrast and polarised light microscopy. The band pattern at rest-length has been determined in flies killed in osmium tetroxide vapour while their wings remained in the resting position. All other observations have been made on unfixed fibrils. Although length changes in situ are probably very slight (about 2 per cent), isolated fibrils, by treatment with crude muscle extract or with ATP, can be induced to elongate to 104 per cent rest-length, or to shorten by 8 per cent but no more. Over the range 98 to 104 per cent rest-length, experimentally induced length changes are reversible. The fibrils can also be stretched beyond 104 per cent rest-length, but the process is irreversible. During the course of glycerol extraction the fibrils elongate to 104 per cent rest-length. 2. The changes in band pattern observed over the range 104 to 92 per cent rest-length are qualitatively the same as the changes observed over a wider range (about 130 to 40 per cent rest-length) in the skeletal myofibrils of rabbits. The earlier stages of shortening appear to be effected by retraction of the I bands into the A bands where they fill up the H zones. No evidence has been found that any changes in band pattern are due to a migration of the A substance. 3. Two components of the sarcomere can be extracted from it and a third component remains behind. These three components, which have also been demonstrated in skeletal myofibrils of the rabbit, where they behave in the same way, are: (a) the A substance which does not change its position as the fibril changes its length, and which can be extracted by the same procedures as remove myosin (shown elsewhere to be the A substance) from rabbit fibrils; (b) a material which extends from the Z lines to the borders of the H zone and which moves inwards during contraction and outwards during elongation; it can capture rabbit myosin from solution and form with it a contractile system, and it is thought to be actin; (c) a "backbone" or stroma bearing Z and M lines. 4. Since all these features of the cross-striation are the same in the insect fibrils as in rabbit fibrils, it is considered very probable that the sarcomere is similarly organised in both types of muscle and contracts by essentially the same mechanism.  相似文献   

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