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1.
Eight aeolid opisthobranch molluscs of the subfamilies Facelininae, Favorininae, and Herviellinae are reported from Tanzanian waters, and two species from Northwestern India. New records from Queensland, Australia greatly extend the range of two species reported from Tanzania. Phidiana militaris (Alder & Hancock) and P. indica (Bergh) are shown to be distinct and a species from New Zealand, originally identified as P. militaris , is shown to be new. P. bourailli (Risbec), previously reported only from New Caledonia, is described from Tanzania, as is a new species of Phidiana. Favorinus japonicus Baba is reported from Tanzania, the first published record outside Japan, a new species of Godiva is described from Tanzania and Queensland, and three new species of Sakuraeolis are described, one from India and two from Tanzania. A new species of Herviella is described from Tanzania.  相似文献   

2.
Abstract:  The holotype of Dollosuchus dixoni (Owen) from the Early–Middle Eocene Bracklesham Beds of England is a set of mandibular fragments that cannot be distinguished from corresponding parts of other longirostrine crocodylians. An isolated humerus from the Bracklesham Beds is consistent with a gavialoid, but it cannot be referred to the holotype of D. dixoni . The name Dollosuchoides densmorei is established for the well-preserved skull and skeleton of a tomistomine from the Middle Eocene of Belgium that had been referred to D. dixoni . It can be clearly distinguished from the basal tomistomine ' Crocodilus ' spenceri Buckland from the Lower Eocene of England, which cannot be referred to Dollosuchoides and is provisionally referred to Kentisuchus Mook. Although basal within Tomistominae, Dollosuchoides is more closely related to Tomistoma than to Kentisuchus .  相似文献   

3.
Abstract Vespitinea gurkharum gen. et sp.n. is described from specimens reared from a bracket-fungus ( Ganoderma - Polyporaceae) from lowland rain-forest in Brunei. This striking wasp-like moth is suggested to be a Batesian mimic of species of Vespidae and Pompilidae (Hymenoptera) and the first example of this mimicry type recorded from the Tineoidea. Abdominal, eye and wing-coupling modifications suggest that it is diurnal and a behavioural mimic. The systematic position of Vespitinea is discussed with reference to biology and adult and larval morphology.  相似文献   

4.
道虎沟化石层分布于内蒙古宁城县道虎沟以及毗邻的河北北部和辽宁西部等地,已报道4种有尾类、1个无尾类蝌蚪、1个幼年蜥蜴、3种带原始羽毛的兽脚类恐龙、2种翼龙、3种哺乳动物以及双壳类、叶肢介、昆虫和植物等化石(有学者称之为"前热河生物群")。该层位比热河群义县组低,但地层划分存在争议:中侏罗统九龙山组、上侏罗统道虎沟组和下白垩统热河群均有报道。本文研究的道虎沟蜥蜴是该地点发现的第2个蜥蜴化石,其身体细长,为一幼年个体;前颌骨、顶骨和额骨均成对;上颌骨的面突高;后额骨和后眶骨不愈合;后额骨较大,但可能未进入上颞孔;后眶骨具宽的后突;牙齿小而尖锐,结构简单且可能为侧生;头骨的眶前区较长;具27个荐前椎;虽然未成年但个体较大;未见真皮骨板;手掌和四肢较长。上述特征组合区别于所有现生蜥蜴类,四肢比例也与其他蜥蜴有较大区别。欧美中侏罗世-早白垩世的小盗蜥(Parviraptor)和蒙古早白垩世的一个幼年个体(可能属于壁虎型类)与道虎沟标本比较相似。头骨特征和较大的荐前椎数目显示道虎沟标本可能属于硬舌蜥类(scleroglossan)。但因标本为幼年个体,本文暂将它归入有鳞类属种未定(Squamata gen.et sp.indet.)。测量数据显示,道虎沟标本的手掌和前肢相对较长;该特征常见于适应攀爬的蜥蜴种类,似可显示攀爬习性。但肢体比例可能会随身体增长而发生变化,所以此生活习性并非定论。  相似文献   

5.
The major cell surface protein of a strain of human fetal lung fibroblasts is a 220,000 dalton glycoprotein termed fibronectin. Fibronectin is released from fibroblasts into the culture medium with a half-time of about 25 hours. The release occurs with an initial (0–3 hours) rapid phase followed by a second (3–48 hours) slower phase. Release of fibronectin occurs in a stoichiometric fashion. All of the fibronectin released from the cells is quantitatively recovered from the culture media as a similar sized soluble glycoprotein. Thus, release of fibronectin from normal human fibroblasts results from mechanisms other than extensive degradation of the protein.  相似文献   

6.
Vema levinae Warén, sp. n. is described from a submarine volcano off western Mexico. The type species of Rokopella and Veleropilina are redescribed, the usage of the names is discussed and Rokopella and Veleropilina are recognized as valid genera in Neopilinidae. Rokopella euglypta (Dautzenberg & Fischer, 1897) is redescribed from shells and a single live specimen taken from seamounts south of the Azores, from a depth of 1200–1600 m. Tectura reticulata Seguenza, 1876 (Gastropoda, 'Acmaeidae', southern Italy, Upper Pliocene/Lower Pleistocene) is considered to have been based on the monoplacophoran species previously known as Neopilina zografi from the Mediterranean, and is classified in the genus Veleropilina. Veleropilina zografi (Dautzenberg & Fischer, 1896) is redescribed based on shells from several seamounts south of the Azores. It is considered distinct from Rokopella euglypta and classified in the genus Veleropilina. An undescribed species of Veleropilina from a seamount off southern Baja California is reported, figured and discussed but not formally described.  相似文献   

7.
In many less developed countries economic development is not in conformity with the actual level of consumption. In part this is to be explained by the huge informal sector that is not included in official statistics. However, using Suriname as a case study, it is argued in this article that a significant part of the discrepancies can be explained from private household transfers from The Netherlands. Migration is not a loss in all respects, but sometimes an asset. In contrast the remittances from temporarily migrated workers, the transfers from people constituting a transnational community cannot be taken for granted. This private family aid expresses personal commitments at the primordial level, and is therefore a kind of moral capital. Depending on the size of the migrated community and the moral commitments of their members, these transfers constitute a net surplus from the former metropolis to the periphery.  相似文献   

8.
Spectral properties of solutions containing mixtures of chlorophyll a and chlorophyll c are investigated. The yield of excitation energy migration from chlorophyll c to chlorophyll a is obtained ranging from 23 to 48% dependent on the used dye concentrations. The back transfer from chlorophyll a to chlorophyll c is negligible. The shape of the polarization excitation spectrum of chlorophyll c in the Soret band region is less composed than that of chlorophyll a. Depolarization of chlorophyll a fluorescence by chlorophyll c is in agreement with the conclusion drawn from fluorescence quenching that excitation energy migrates from chlorophyll c to chlorophyll a.  相似文献   

9.
What differentiates the living from the nonliving? What is life? These are perennial questions that have occupied minds since the beginning of cultures. The search for a clear demarcation between animate and inanimate is a reflection of the human tendency to create borders, not only physical but also conceptual. It is obvious that what we call a living creature, either bacteria or organism, has distinct properties from those of the normally called nonliving. However, searching beyond dichotomies and from a global, more abstract, perspective on natural laws, a clear partition of matter into animate and inanimate becomes fuzzy. Based on concepts from a variety of fields of research, the emerging notion is that common principles of biological and nonbiological organization indicate that natural phenomena arise and evolve from a central theme captured by the process of information exchange. Thus, a relatively simple universal logic that rules the evolution of natural phenomena can be unveiled from the apparent complexity of the natural world.  相似文献   

10.
Rising from a chair is a task essential for independent living. Many elderly persons have difficulty with this task. Previous studies have drawn conflicting conclusions as to the role of strength in limiting the ability to rise from a chair. The purpose of this study is to determine the role of knee extensor strength in rising from a chair in the functionally impaired elderly. It is hypothesized that knee extensor strength limits the minimum chair height from which a subject can rise in the functionally impaired elderly, but not in the young. Studying both young healthy adults and functionally impaired elderly showed that required joint moment increased monotonically with decreasing chair height. Further, the elderly used significantly more of their available strength to rise from any chair height, and their mean required knee moment was 97% of the available strength when rising from the lowest chair height from which they could successfully rise. These data suggest that strength is a limiting factor in determining the minimum chair height from which the functionally impaired elderly may rise  相似文献   

11.
An important prediction from game theory is that resource value influences the level to which competitors will escalate conflict. An earlier study considered whether this prediction applies to the male–male interactions of Hypoblemum albovittatum, a jumping spider (Salticidae) from New Zealand. The males of this species escalated conflicts in the presence of a moving mount made from a conspecific female. However, because the control was only a similar-sized motionless cork, an alternative hypothesis (that the cue for escalation is seeing movement of any female-size object, rather than seeing specifically a female) was not ruled out. Here we show that a moving cork, without a mount present, is indeed sufficient to cause males to escalate, but a moving mount (made from a conspecific female) causes males to escalate further. The level of escalation in the presence of a moving mount made from prey (housefly) or from a rival (conspecific male) did not differ significantly from the level of escalation when only a moving cork was present. These findings suggest that, although seeing a moving object similar in size to a conspecific female is sufficient for priming males to escalate, males can also discern by sight that specifically a female is present and, when they have this precise information, they make strategic decisions to escalate conflict further.  相似文献   

12.
The female of a new species of Halticoptera is described from a single specimen from Britain, and the male and female of a second new species are described from material from Britain and Czechoslovakia. Halticop-terina triannulata is recorded from Britain for the first time.  相似文献   

13.
The illness-death model is the simplest multistate model where the transition from the initial state 0 to the absorbing state 2 may involve an intermediate state 1 (e.g., disease relapse). The impact of the transition into state 1 on the subsequent transition hazard to state 2 enables insight to be gained into the disease evolution. The standard approach of analysis is modeling the transition hazards from 0 to 2 and from 1 to 2, including time to illness as a time-varying covariate and measuring time from origin even after transition into state 1. The hazard from 1 to 2 can be also modeled separately using only patients in state 1, measuring time from illness and including time to illness as a fixed covariate. A recently proposed approach is a model where time after the transition into state 1 is measured in both scales and time to illness is included as a time-varying covariate. Another possibility is a model where time after transition into state 1 is measured only from illness and time to illness is included as a fixed covariate. Through theoretical reasoning and simulation protocols, we discuss the use of these models and we develop a practical strategy aiming to (a) validate the properties of the illness-death process, (b) estimate the impact of time to illness on the hazard from state 1 to 2, and (c) quantify the impact that the transition into state 1 has on the hazard of the absorbing state. The strategy is also applied to a literature dataset on diabetes.  相似文献   

14.
The cranial capacity of Olduvai Hominid 7 is estimated to be 690 cc, with a standard uncertainty range of 538 to 868 cc. The estimate is derived from a systematic consideration of the relationships between Bregma-Asterion chords and cranial capacities obtained from a large sample of Homo sapiens and Pan troglodytes and from available fossil hominids. The estimation technique is applicable to other characters and specimens.  相似文献   

15.
Ishida T  Nakamura S  Shimizu K 《Proteins》2006,64(4):940-947
We developed a novel knowledge-based residue environment potential for assessing the quality of protein structures in protein structure prediction. The potential uses the contact number of residues in a protein structure and the absolute contact number of residues predicted from its amino acid sequence using a new prediction method based on a support vector regression (SVR). The contact number of an amino acid residue in a protein structure is defined by the number of residues around a given residue. First, the contact number of each residue is predicted using SVR from an amino acid sequence of a target protein. Then, the potential of the protein structure is calculated from the probability distribution of the native contact numbers corresponding to the predicted ones. The performance of this potential is compared with other score functions using decoy structures to identify both native structure from other structures and near-native structures from nonnative structures. This potential improves not only the ability to identify native structures from other structures but also the ability to discriminate near-native structures from nonnative structures.  相似文献   

16.
Heller G  Qin J 《Biometrics》2001,57(3):813-817
We consider the problem of estimation and inference on the mixture parameter in the two-sample problem when sample data from the two distributions as well as from a third population consisting of a mixture of the two are used. Under a general nonparametric model, where the relationship between the two populations is unspecified, we develop a pairwise rank-based likelihood. Simultaneous inference on the mixture proportion and a parameter representing the probability an observation from one population is greater than an observation from the other population is based on this likelihood. Under some regularity conditions, it is shown that the maximum pairwise rank likelihood estimator is consistent and has an asymptotic normal distribution. Simulation results indicate that the performance of this statistic is satisfactory. The methodology is demonstrated on a data set in prostate cancer.  相似文献   

17.
Five new species of Fissistigma are described from Borneo. Fissistigma brevistipitatum sp. nov. is a species of lowland and hill forest mostly recorded from Sabah. Fissistigma bygravei sp. nov. is similar to F. hypoglaucum (Miq.) Merr. of the Malay Peninsula and Sumatra. Fissistigma carrii sp. nov. is from Mount Kinabalu. Fissistigma crassicaule is a robust plant known from a couple of collections from Sarawak. Fissistigma montanum sp. nov. is a species from hill and montane forest recorded from Brunei, Sabah and Sarawak. A new combination in Fissistigma is made for Melodorum multivenium Diels. Two recently described species of Fissistigma from Borneo ( F. cordifolium Irawan and F. magnisepalum Irawan) are reduced to synonymy of Friesodielsia excisa (Miq.) Steenis and Friesodielsia affinis (Hook. f. & Thomson) D. Das, respectively. Both species of Friesodielsia are lectotypified.  相似文献   

18.
New land tortoises (Testudines: Testudinidae) from the Miocene of Africa   总被引:1,自引:0,他引:1  
The described fossil testudinids from the Miocene of Africa are reviewed. Geochelone stromeri sp. nov . is described from Lower Pliocene (Langebaanweg) and Miocene (Namib) specimens. Kinixys erosa , an extant species, is reported from Songhor Hill. Chersina sp. is reported from Arrisdrift. Impregnochelys pachytectis gen. et sp. nov . is described from Rusinga Island, Kenya, and is unique in having the anterior shell opening orientated ventrally and in having struts on the internal surface of the neurals, but shares with Kinixys a unique epiplastron shape, a high number of axillary scutes and unique orientation of the head of the femur.  相似文献   

19.
Precise sampling from whole lobes of mouse lungs fixed in the inflated state and embedded in epoxy resin can be not only feasible but also efficient. A 1 μm section is cut from an embedded lobe with a rotary microtome and a steel knife. This section is stained and photographed, and from it a 35 × enlarged print is prepared. A grid of transparent plastic scored with 35 mm squares, lettered vertically and numbered horizontally, is superimposed over the photograph. The area chosen for electron microscopy thus becomes identifiable by a letter-number designation obtained from the grid. This area is then located by light microscopy on a 2 mm slice taken from the block from which the 1 μm section was cut, by use of oblique illumination and the calibrated mechanical stage of the light microscope. A block of 1.3 mm diameter is removed for electron microscopy from the tissue by a rotatable circular spring-loaded punch screwed into the objective turret of the microscope. The removed cylinder is mounted on a metal stub and ultrathin sections cut from the faced tissue. The method is as equally suitable for the examination of other tissues, particularly when large areas and multiple sampling may be required.  相似文献   

20.
Results are presented from time-integrated measurements of soft X-ray emission from Z-pinches during the implosion of simple and nested wire arrays. The blackening density distribution obtained with the help of a pinhole camera is recalculated into the time-integrated Z-pinch radiance. It is found that, in the case of a simple wire array, up to 70% of the total SXR energy emitted during a discharge is radiated from the axial region, the rest of energy being radiated from plasma jets, whereas in the case of a nested wire array, more than 90% of the SXR energy is radiated from the axial region.  相似文献   

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