的的喀喀湖畔的渔民

的的喀喀湖位于南美洲东海岸边连绵不断的安第斯山脉中,方圆七千平方公里,是世界上最大的淡水湖之一。自古以來这里流傳有許多赞颂它的富饒和美丽的傳說。据說在湖底藏有昔日印加族富翁的无数財宝:有全由黄金和宝石嵌成的都市以及当地居民在西班牙和葡萄牙占领者入侵前埋藏的珠宝飾物。諸如此类的傳說真是数以千計。但传說毕竟是传說,人們的現     

的的喀喀湖的高原人家

正秘鲁的印加文化名城不仅仅有库斯科,马丘比丘,南部一个叫做"普诺"的城市,这座高原谜城,是探索印加帝国源头——的的喀喀湖的起点。普诺(Puno),坐落于世界上海拔最高的淡水湖——的的喀喀湖(Lake Titicaca)岸边,东邻玻利维亚,游客的必经之地。我来到瓦萨帕塔公园(Cerro Huajsapata),那里可以俯瞰城市风光。一座雕像矗立在山顶,曼科·卡帕克(Manqu Qhapaq)——     

循环群的Burnside环的增广理想的商群的结构

本文给出了由有限循环群出发构造的Burnside环的增广理想的基底,并讨论了它们的n次幂与n 1次幂之商,完整地给出了这类商群的结构.     

函数的周期性与它的图象的对称性的关系

函数的周期性与它的图象的对称性的关系张沛和（嘉应大学数学系梅州５１４０００）约定：函数ｙ三八时的图象简称为图象，并用符号Ｔ表示它二图象的对称轴仅限于垂直于。轴的直线。定义：对函数ｙ一．ｆ（），若存在某一个正数Ｔ．｛ｋ得对于函数的定义域内所有Ｘ都成立，...     

群的元素的阶的某些问题

讨论了周期群与自由群的元素的阶,研究环的加群的元素的阶并建立环的特征数的概念.给出了群的元素的阶概念的两个推广:元素对于子群的阶、半群的元素的阶.     

葡萄酒:年青的 盛年的 衰老的

酒的年龄,谁长谁短? 普通的白葡萄酒通常只有两年生命,用2001年收获的果实酿出的白葡萄酒,2002年春末应该是它口味最成熟的时候。普通红葡萄     

扩充的Sturmian序列的性质的补充

Sturmian序列是具有最低复杂性的一类符号序列,对Sturmian序列进行扩充,使其更具一般性。本文对扩充的Sturmian序列进行了进一步的研究,从而使其应用更加广泛。     

常用的求函数极限的方法的探讨

由于极限在微积分中的基础地位,本文结合实例,重点介绍十二种常用的求极限的方法。     

关于Sn的元素的阶的集合

用Ｏ＿ｎ表示ｎ次对称群Ｓ＿ｎ的元素的阶的集合。本文综述Ｏ＿ｎ的两种刻划Ｏｎ＝｛［ｎ＿１，ｎ＿２，…，ｎ＿ｕ］｜ｎ＿ｉ是正整数，且ｎ＿ｉ≤ｎ｝，为互异质数，且与两种求法，并且给出用计算机求得的Ｏ＿ｎ的一些结果。最后，对于Ｏ＿ｎ提出一些问题，以作进一步研究．     

扩充的Sturmian序列的性质的补充

Sturmian序列是具有最低复杂性的一类符号序列,对Sturmian序列进行扩充,使其更具一般性.本文对扩充的Sturmian序列进行了进一步的研究,从而使其应用更加广泛.     

Affinities and functional morphology of the Middle Cambrian ornamented tubules from West Hunan, China

Problematic phosphatic tubular microfossils with ornamented sculptures are documented to exist in limestones of the upper Middle Cambrian Huaqiao Formation at the Paibi section and the Wangcun section in West Hunan, China. Two morphological patterns, including Ornamented Tube Form I and Ornamented Tube Form II are described. Based on the analysis of the preservation, wall structure and composition of the fossils, it is deduced that these ornamented tubes may represent carapace spines of some Cambrian arthropods with phosphatic carapaces, such as bradoriid crustaceans. Analysis of functional morphology indicates that the sclerites may rather be considered of a defensive than grasping function on the original organism body.     

湘西花垣中寒武统具表面装饰的管状微体化石

对采自湘西花垣县排碧剖面中寒武统花桥组灰岩中具表面装饰的磷灰石质管状化石（Ornamented tubes）进行了研究,依据化石的壳面装饰特征,建立了3形态类型：Ornamented Tube Form Ⅰ,Ornamented Tube Form Ⅱ 和 Ornamented Tube Form Ⅲ。其中Ⅰ型壳体表面装饰有尖细的小刺,多数标本壳刺成行排列,行间存在宽约0.01～0.05 mm的间隔;Ⅱ 型管体表面具有零散稀疏而不规则分布的斑疹状壳饰,壳体微微向外弯曲的一侧具有一列粗壮的呈锯齿状排列的脊刺;Ⅲ型整个壳体表面布满圆形、卵圆形瘤状壳饰,壳饰中空,与壳体内腔相通,壳体微微向外弯曲的一侧具有一列粗壮的呈羽状排列的脊刺。从壳体形态、表面装饰特征分析,这类管状化石可能是节肢动物(如高肌虫类)生物体壳瓣上的前刺或背部的刺等管状硬体构造。     

Phylogeny and life habits of Early Arthropods-Predation in the Early Cambrian Sea

We investigated two new arthropods from the Maotianshan-Shale fauna of southern China in the course of our research on life strategies, particularly predation, in Early Cambrian marine macrofaunal biota. One form clearly belongs to the so-called "great-appendage" arthropods, animals that were, most likely, active predators catching prey with their first pair of large, specialized frontoventral appendages. Based on this, we hypothesize that the new species and many others, if not all, of the "great-appendage" arthropods were derivatives of the chelicerate stem lineage and not forms having branched off at different nodes along the evolutionary lineage of the Arthropoda. Rather, we consider the "great-appendage" arthropods as belonging to a monophyletic clade, which modified autapomorphically their first pair of appendages (antennae in general arthropod terminology) into raptorial organs for food capture. The second new form resembles another Maotianshan-Shale arthropod, Fuxianhuia protensa, in sharing a head made of only two separate segments, a small segment bearing oval eyes laterally, and another bearing a large tergite, which forms a wide shield freely overhanging the subsequent narrow trunk segments. This segment bears a single pair of rather short anteriorly directed uniramous appendages, considered as the "still" limb-shaped antennae. Particularly the evolutionary status of head and limbs of these two forms suggests that both are representatives of the early part of the stem lineage toward the crown-group of Arthropoda, the Euarthropoda. These forms appear rather unspecialized, but may have been but simple predators. This adds to our hypothesis that predation was a common, if not dominant feeding strategy in the Cambrian, at least for arthropods.     

New anomalocardid frontal appendages from the Guanshan biota, eastern Yunnan

Anomalocaridids were large predators of the Cambrian seas at the top of the trophic pyramid. Complete anomalocaridid specimens have been rarely discovered and the rigid isolated frontal appendages and mouthparts are more commonly preserved. Here we study new material of the frontal appendages from the Wulongqing Formation, Cambrian Stage 4, Series 2 near Kunming, eastern Yunnan. Two new forms of anomalocaridid frontal appendages are described, namely Anomalocaris kunmingensis sp. nov. and Paranomalocaris multisegmentalis gen. nov., sp. nov. The frontal appendage of A. kunmingensis sp. nov. probably comprises 15 podomeres of which the first one has a weakened skeletoned, the second one is armed with small spines, and the third one is armed with remarkably robust proximal ventral spines with 6 anisomerous auxiliary spines; paired auxiliary spines are associated with podomeres 4–14; podomeres 12–14 are armed with paired dorsal spines, and the last podomere bears 2 distal spines, one spine distinctly larger than the other. The frontal appendage of P. multisegmentalis tapered backwards, consisting of 22 visible podomeres; the most ventral spine is armed with 5 pairs of auxiliary spines, and podomeres 12–21 bear dorsal spines, the last podomere with 2 small distal spines. The new material provides additional evidence for our understanding of the diversity of anomalocaridids in the Cambrian. The morphology of these new finds may indicate the importance of different feeding strategies of anomalocaridids in the Cambrian ecosystem.     

A giant Ordovician anomalocaridid

Anomalocaridids, giant lightly sclerotized invertebrate predators, occur in a number of exceptionally preserved early and middle Cambrian (542-501?million years ago) biotas and have come to symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair of anterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups--but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal. Phylogenetic analyses support a position of anomalocaridids in the arthropod stem, as a sister group to the euarthropods. The anomalocaridids were the largest animals in Cambrian communities. The youngest unequivocal examples occur in the middle Cambrian Marjum Formation of Utah but an arthropod retaining some anomalocaridid characteristics is present in the Devonian of Germany. Here we report the post-Cambrian occurrence of anomalocaridids, from the Early Ordovician (488-472?million years ago) Fezouata Biota in southeastern Morocco, including specimens larger than any in Cambrian biotas. These giant animals were an important element of some marine communities for about 30?million years longer than previously realized. The Moroccan specimens confirm the presence of a dorsal array of flexible blades attached to a transverse rachis on the trunk segments; these blades probably functioned as gills.     

A venomous arthropod in the Early Cambrian Sea

A number of recently evolved animals possess poison glands for feeding and/or defense.However,examples of such animals are rare in the fossil record.We report a fossil arthropod Isoxys curvirostratus from the Early Cambrian Chengjiang biota of China.This species is regarded as the oldest known venomous arthropod based on the presence of venomous glands in its head region.The adult animal is 2-5 cm long and the body is covered entirely with a carapace.The presence of large stalk eyes and a pair of stout grasping appendages with a terminal spine suggest it was raptorial.Interestingly,the two pear-shaped,three-dimensionally preserved objects that are present in the head region and at the base of the grasping appendages closely resemble the venom glands of some living arthropods in size,shape,and position.These features indicate that the presence of venomous predators could date back 520 million years.Furthermore,our observations suggest that the feeding strategies and organs adapted for this purpose had already reached a high level of diversity and anatomical sophistication in the Early Cambrian ecosystems.     

Lower Cambrian small shelly faunas from Zhejiang (China)and their biostratigraphical implications

Despite a long history of research on the Early Cambrian in China most available data on small skeletal fossils concern fossil associations of the shallow carbonate platform. Information on skeletal fossils from marginal shelf environments of the Yangtze Platform is scanty, which may reflect the rarity of fossils in deeper sedimentary environments but is also due to limitation of carbonate distribution and outcrops, difficulties in fossil extraction, and a general research focus on the Precambrian-Cambrian boundary beds on the carbonate platform. Here we present a documentation of Meishucunian to Qiongzhusian small skeletal fossils from the lower Hetang Formation and the chert unit at its base from the Jiangshan region, Zhejiang Province, representing a relatively deep shelf environment compared to the inner shelf region. The earliest association (Meishucunian) from the chert unit underlying the Hetang Formation is mainly characterized by the occurrence of Protohertzina anabarica, P. unguliformis, Fengzuella zhejiangensis, and Kaiyangites novilis, which differs somewhat in composition from SSF-associations of typical inner shelf deposits. The enigmatic skeletal fossil Fengzuella zhejiangensis, which exhibits an unusual secretional growth mode previously unrecognized from the Early Cambrian, is described in detail. A younger (Qiongzhusian) fossil association contains numerous arthropod remains, such as disarticulated spines of arthropods (Jiangshanodus- and Kijacus-type), which have previously been considered as conodont-like fossils, and bradoriid valves.     

New observations of the lobopod-like worm Facivermis from the Early Cambrian Chengjiang Lagersttte

Facivermis yunnanicus （Hou ＆ Chen, 1989）, from the Early Cambrian Chengjiang Lagerstatte, a worm-like fossil with 5 pairs of tentacles and a perceived shrunken end, has been regarded as related to polychaetes, later it has been variously interpreted as Iobopods, Pentastoma and Iophophorates. Newly discovered complete specimens by the ELI field team show that the taxon has, in addition to the 5 pairs of appendages, a pear-shaped trunk end bearing two or three circles of hooks. Accordingly based on these important morphological characters, reconsideration of its affinities is provided and the taxonomy is remedied herein. Because the five pairs of appendages of Facivermis yunnanicus resemble the appendages of the fore-trunk of Iobopod Miraluolishania （Liu ＆ Shu, 2004）, it seems that they are homologous structures. Therefore, the affinities of Facivermis are regarded here as being close to the Iobopods, in addition, the lobe-like appendages of Facivermis are very crucial to exploring the origin of the appendages of Iobopods and arthropods.     

The earliest-known ancestors of Recent Priapulomorpha from the Early Cambrian Chengjiang Lagersttte

It was suggested and eventually has been profferedthat the representatives of all extant phyla, including someminor group, occurred during the Cambrian radia-tions[1—10]. Many priapulid-like fossil worms have beenreported from Cambrian Lagerst?tten, such as the EarlyCambrian Chengjiang Lagerst?tte[11—16], the Middle Cam-brian Burgess Shale[17], and the Middle Cambrian Kailifauna[18]. The palaeoscolecidan worms from these Lager-st?tten have been regarded as either a stem group of thepri…     

The earliest-known ancestors of Recent Priapulomorpha from the Early Cambrian Chengjiang Lagerstaette

The taxonomy of an early ancestor of Recent Priapulidae, Xiaoheiqingella peculiaris (= Yunnanpriapulus halteroformis Huang et al., 2004) from the Early Cambrian Chengjiang fossil Lagerstaette, is revised. Morphological characters comprise a pair of caudal appendages rather than a single appendage flanking the trunk end and a possible urogenital duct found inside the preanal region. An additional extremely rare fossil priapulid worm, Paratubiluchus bicaudatus gen. nov., sp. nov. is also described herein. Its diagnostic characters are: an introvert bearing 25 longitudinal rows of scalids, a distinct neck region, no annulus on the oval trunk, and a pair of caudal appendages. The proportion of body parts is similar in size to that of loricate larvae of Recent priapulids and larva-formed Palaeopriapulitidae. Taking account of the features of Xiaoheiqingella, bicaudal appendages are considered to be a synapomorphy of Priapulidae and Tubiluchidae. Paratubiluchus gen. nov. is most likely a candidate for the ancestor of the Tubiluchidae; it probably originated from a larva-formed priapulid with 25 rows of scalids, thus representing an intermediate link between the priapulids in mature-form and the priapulids with lorica.