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1.
J. L. Wilkens T. Kuramoto 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1998,168(7):483-490
The decapod cardiovascular system consists of a single ventricle that pumps blood into seven arteries; previous work has
shown that the outflow distribution patterns of intact animals are variable. In the present study, flow recordings were made
from pairs of arteries in semi-isolated hearts whilst different cardioactive hormones were infused into the heart. Each hormone
(5-hydroxytryptamine, octopamine, dopamine, proctolin and F1) changed the outflow pattern, heart rate and ventricular pressure
in a unique way. The probable sites of hormone action are the cardioarterial valves located at the origin of each artery except
one, the dorsal abdominal. Outflow from the dorsal abdominal is controlled downstream by valves located at the origin of the
segmental lateral arteries. The responses to a particular hormone were sometimes different between the hearts of American
and Japanese lobsters.
Accepted: 11 May 1998 相似文献
2.
Jerome Goddard 《Journal of vector ecology》2009,34(2):238-242
Rickettsia parkeri, a member of the spotted fever group rickettsias, was first described in 1939 and was thought to be non‐pathogenic until recently, when it was found to cause a spotted fever‐like illness in humans and areas of necrosis (eschars) at the sites of tick bites. Accordingly, there is currently much interest in this emerging pathogen. In this study, all published articles concerning R. parkeri were reviewed and analyzed for evidence of relatedness among this agent and other spotted fever group (SFG) rickettsiae which also produce similar clinical syndromes and/or eschars, including R. conorii, R. africae, and R. sibirica. A synthesis of the historical (antigenic) and recent (molecular) data supporting a phylogenetic sub‐grouping of these SFG organisms is presented and comments are offered about the taxonomy of rickettsial organisms in general, and R. parkeri in particular. 相似文献
3.
MORGAN PERKINS 《American anthropologist》2004,106(3):595-599
This review essay of Across Borders: Beadwork in Iroquois Life focuses on the display of beadwork as a cultural practice that has evolved significantly throughout its history while remaining central to Iroquois identity. The exhibition draws on historical documentation, objects, and imagery that depict the varied uses of beadwork as ritual objects, sources of income, markers of identity, and as works of art. The content and narrative for the display was developed through a broad collaboration between curators, scholars, artists, and members of two Iroquois communities. The changing and continued importance of beadwork is reflected in the adaptation of materials and styles for different forms of production and use. Across Borders places Iroquois beadwork in a broad context while concentrating on specific forms and meanings that are attached to beadwork, whether created in community gatherings or by individual artists. 相似文献
4.
SHOMITA MUKHERJEE COLIN GROVES 《Biological journal of the Linnean Society. Linnean Society of London》2007,92(1):163-172
There is a striking difference in body size of jungle cats ( Felis chaus ) in the west and the east of their distribution, with Israeli cats being 43% heavier than Indian cats. We tested the hypothesis that increasing competition from other small felids towards the east is responsible for the difference in body size. We measured jungle cat skulls for eight cranial and dental variables and related these to independent variables such as species richness (local and regional), latitude, longitude, temperature, and precipitation. Data from a narrow band between latitudes 24.0°N and 33.9°N, where Bergmann's rule was largely not observed, showed that the western population (≤ 50.0°E longitude) of jungle cats is larger than the eastern (> 60.0°E longitude) population with the size difference being most evident in the upper carnassials (P4 L). Species richness at the regional level showed a significant negative relation to P4 L. An even spacing in condylobasal length for a small-cat guild from India through null model analysis indicated the occurrence of character displacement. The results support the hypothesis that competition is responsible for geographical variation in jungle cat body size in the region where Bergmann's rule does not apply. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 163–172. 相似文献
5.
6.
L. L. WALLACE 《The New phytologist》1987,105(4):619-632
7.
Mehmet Yaar can 《American journal of physical anthropology》1989,78(1):3-8
This study analyzes and compares the dental size variation and sexual dimorphism of the Highland Beach Mound people, a late southeastern prehistoric aboriginal Florida population (ca. 800-1200 AD) with a somewhat earlier midwestern group (ca. 200-800 AD) and an Archaic sample (ca. 4160-2558 BC). The lengths and breadths of maxillary and mandibular permanent teeth of 99 individuals were measured, and crown surface areas were calculated for the molars. Results indicated that there was little sexual dimorphism. Only the mesiodistal dimensions of the upper P2 and lower C were significantly different at the P less than 0.05 level. In terms of dental size, what appears to be a chronologically based reduction in most points of comparison was seen in all three groups, with the exception of the molars, which were larger in the Highland Beach sample than in the earlier Schultz Mound. 相似文献
8.
9.
C. M. Brasier 《Mycopathologia》1991,115(3):151-161
The aggressive subgroup of the Dutch elm disease pathogen Ophiostoma ulmi (Buism.) Nannf. syn. Ceratocystis ulmi (Buism.) Moreau is named as a new species, O. novo-ulmi, and is thereby separated from the old non-aggressive subgroup, which is retained as O. ulmi. O. novo-ulmi differs from O. ulmi in colony morphology, growth rate, optimum temperature for growth, perithecial neck length, pathogenicity to elm, bark colonising ability, cerato-ulmin protein production, synnemetal and protoperithecial production, mating type frequency, protein and isozyme polymorphisms, mitochondrial DNA and nuclear DNA polymorphisms, and mitochondrial DNA size. In addition, a strong unidirectional fertility barrier operates between the two species, while their hybrids show remarkable variation, poor fitness, and many are infertile. These aspects are summarised. New information on perithecial dimensions is presented. O. ulmi is redefined and a neotype designated. The status of the Eurasian and North American races of O. novo-ulmi is currently under investigation.Abbreviations EAN
Eurasian race
- NAN
North American race 相似文献
10.
The electrophoretic patterns of the enzyme alcohol dehydrogenase (ADH) from Anastrepha fraterculus and A. obliqua were studied. Two loci were found to code for the enzyme in A. fraterculus, and three in A. obliqua. In both species, all isozymes were active in third-instar larvae. A cationic isozyme (Adh-1) was active mainly in the visceral fat body of both species. In A. fraterculus, the locus had an anionic polymorphic isozyme (Adh-3) that was detected in the parietal fat body. In addition to these two loci, a third locus for an anionic isozyme (Adh-2), which was active in the digestive tube of larvae, was present in A. obliqua and probably resulted from gene duplication. For both species, multiple forms of the isozymes are formed by binding of an NAD-carbonyl compound, as in Drosophila melanogaster. Both larvae and early pupae of A. obliqua had almost twice the specific ADH activity as A. fraterculus. The ethanol content of the host fruit infested with A. obliqua (red mombim) was also higher than that of the host fruit infested with A. fraterculus (guava).This research was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnologico (CNPq-PIG 40.2486/82). 相似文献