首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
We describe the otolith assemblage from the early Miocene (Burdigalian) exposures of the Castillo Formation at the Cerro La Cruz locality (Falcón Basin, Lara State, northwestern Venezuela). The samples were obtained through surface and bulk sampling at distinct stratigraphic levels of the study area. The otolith assemblage from Cerro La Cruz includes 14 families, 25 genera and 30 taxa, of which 20 are reported for first time from the Castillo Formation. These include two new sciaenid taxa, Ctenosciaena angusticaudata nov. sp. and Pareques laraensis nov. sp. The Castillo Formation otolith assemblage represent fishes typical of shallow and near-shore and coral reef associated environments as characterized primarily by a high taxonomic diversity and abundance of Sciaenidae, and the lack of mesopelagic families (Myctophidae). The faunal composition of Cerro La Cruz is similar to other chronological equivalent sedimentary units along the proto-Caribbean area (Pirabas and Cantaure formations; Brazil and Venezuela respectively), though the Castillo Formation fish fauna shows lower taxonomic diversity, suggesting some heterogeneity of the coastal and near shore marine environments along the southern portion of the proto-Caribbean.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:B79F51B8-BC35-4119-8957-84544286868D  相似文献   


4.
5.
In this paper, we present the techno-typological study of level 16 of El Castillo cave (Archaic Aurignacian). In this level, we can identify an important bladelet production from schémas opératoires of unipolar prismatic cores, carinated endscraper and carinated burins types. Besides, we find a specific production of Discoid conception. The retouched blanks, though scanty, are dominated by the Dufour bladelets. Level 16 is in relation with the Archaic Aurignacian at the Cantabrian Iberia, which is present in sites like Cueva Morín, Labeko Koba, Gatzarria, or Isturitz and it also is in relation with the Mediterranean Archaic Aurignacian. Finally, we analyse the different hypotheses about the Initial Upper Paleolithic origin in Europe. The mosaic hypothesis is acceptable for us.  相似文献   

6.
7.
8.
9.
10.
The Brigantian rugose coral Espielia columellata gen. and sp. nov. from the Viséan (Carboniferous) Sierra del Castillo Unit (Córdoba, SW Spain) is described in detail. This phaceloid coral has thick wall and septa, one to three rows of regular dissepiments, thick amygdalophylloid columella, typically aulophylloid tabularium, basically fibrous microstructure, and non-parricidal peripheral increase. It is similar to Cionodendron Benson and Smith, 1923, but differs in the shape of the columella, the structure of the tabularium and in having thicker septa. The genera Rylstonia and Carruthersella have similar structures, but they are solitary and possess well developed cardinal fossulae. The new genus is placed in the subfamily Amygdalophyllinae because of the structure of its tabularium and columella.  相似文献   

11.
12.
13.
Chronic inflammation induced by Helicobacter pylori infection is a critical factor in the development of peptic ulcer disease and gastric cancer. Central to this inflammation is the initiation of pro‐inflammatory signaling cascades within epithelial cells, in particular those mediated by two sensors of bacterial cell wall components, nucleotide‐binding oligomerization domain‐containing protein 1 (NOD1) and alpha‐protein kinase 1 (ALPK1). H pylori is, however, also highly adept at mitigating inflammation in the host, thereby restricting tissue damage and favoring bacterial persistence. H pylori modulates host immune responses by altering cytokine signaling in epithelial and myeloid cells, which results in increased proliferation of regulatory T cells and downregulation of effector T‐cell responses. H pylori vacuolating cytotoxin A (VacA) has been shown to play an important role in the dampening of immune responses and induction of immune tolerance capable of protecting against asthma. It is also possible to generate protective immune responses by immunization with various H pylori antigens or their epitopes, in combination with an adjuvant, though this for now has only been shown in mouse models. Novel non‐toxic adjuvants, consisting of modified bacterial enterotoxins or nanoparticles, have recently been developed that may not only enhance vaccine efficacy, but also help translate candidate vaccines to the clinic. This review will summarize the main discoveries in the past year regarding host immune responses to H pylori infection, as well as the design of new vaccine approaches against this infection.  相似文献   

14.
《Geobios》1999,32(4):538
  相似文献   

15.
16.
To investigate the evolutionary relationships among species of Afrotrichloris, Apochiton, Coelachyrum, Dinebra, Eleusine, Leptochloa, and Schoenefeldia of subtribe Eleusininae, a phylogeny based on DNA sequences from nine gene regions (ITS, rps16-trnK, rps3, rps16, rpoC2, rpl32-trnL, ndhF, ndhA, ccsA) is presented. Previous molecular phylogenies indicated that Coelachyrum was polyphyletic and Schoenefeldia was paraphyletic, with Afrotrichloris embedded within it. Apochiton burttii was embedded in the Coelachyrum clade paired with C. longiglume, Coelachyrumpoiflorum was placed outside of Coelachyrum and sister to Eleusine, and Schoenefeldia is paraphyletic, with its two species forming a grade sister to Afrotrichoris. Our molecular phylogeny supports recognition of a new genus, Schoenefeldiella, and a new combination, Schoenfeldiella transiens. In addition, we provide generic emendations for Coelachyrum, which now includes five species including a new combination proposed here, Coelachyrum burttii, and Eleusine, which now includes 11 species.  相似文献   

17.
18.
The social play behavior of six mammalian species (Rodentia,Pinnipedia, Artiodactyla, Carnivora) is described and compared.Locomotor and Rotational Movements, e.g., jumping, running,and headshaking, occurred in all species and predominated inthe rodent play. These movements are similar in form to anti-predatorand "protective" responses and result in an immediate but temporarycessation of sensory stimulation from conspecifics. Investigation of body odors was the most important stimuluseliciting Locomotor-Rotational Movements in the rodents. Inthe larger mammals, body odor sniffing was enhanced during play,but specialized signals from other sensory modalities elicitedand maintained play interactions. The possible functions ofa heightened exchange of olfactory information during juvenilesocial development are discussed.  相似文献   

19.
Basal cell carcinoma (BCC) is the most common malignancy. Exposure to sunlight is the most important risk factor. Most, if not all, cases of BCC demonstrate overactive Hedgehog signaling. A variety of treatment modalities exist and are selected based on recurrence risk, importance of tissue preservation, patient preference, and extent of disease. The pathogenesis, epidemiology, clinical features, diagnosis, histopathology, and management of BCC will be discussed in this review.  相似文献   

20.
<正> 本书系由昆虫各重要类群的细胞内共生物的专家写成。其重点是:它们形态学的电镜研究、寄主与共生物的相互关系、寄主的免疫系统、共生物的遗传学及基因表达、它们的系统发育和分类等。目前已知,在蟑螂、白蚁、蚂蚁、蝉、蚧虫、蚜虫、蝇类、甲虫及蜱类中均有细胞内共生物。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号