共查询到20条相似文献,搜索用时 15 毫秒
1.
David L Abel 《Theoretical biology & medical modelling》2009,6(1):27-10
Background
Mere possibility is not an adequate basis for asserting scientific plausibility. A precisely defined universal bound is needed beyond which the assertion of plausibility, particularly in life-origin models, can be considered operationally falsified. But can something so seemingly relative and subjective as plausibility ever be quantified? Amazingly, the answer is, "Yes." A method of objectively measuring the plausibility of any chance hypothesis (The Universal Plausibility Metric [UPM]) is presented. A numerical inequality is also provided whereby any chance hypothesis can be definitively falsified when its UPM metric of ξ is < 1 (The Universal Plausibility Principle [UPP]). Both UPM and UPP pre-exist and are independent of any experimental design and data set.Conclusion
No low-probability hypothetical plausibility assertion should survive peer-review without subjection to the UPP inequality standard of formal falsification (ξ < 1). 相似文献2.
D. Jaume 《Hydrobiologia》2008,595(1):219-224
Spelaeogriphaceans and thermosbaenaceans are two orders of eyeless, unpigmented peracarid crustaceans represented by very
few species from subterranean waters. Spelaeogriphaceans occur only in continental waters, either running or still, in limestone
or sandstone caves, or in calcrete aquifers. The four species known are limnic except one occurring in slightly brackish water
loosely associated with an endorheic basin. The Thermosbaenacea are primarily marine, with only 18 species recorded in limnic
conditions or in brackish inland waters whose salinity does not derive from dilution of seawater. They occur in limestone
caves, the interstitial medium associated to alluvial deposits, or in thermo-mineral springs. Spelaeogriphaceans are found
on the southern continents, in ancient cratons not affected by sea transgressions at least since the Early Cretaceous, when
Gondwana started to break-up. The former integration of these terranes into Gondwana suggests that the penetration of spelaeogriphaceans
in continental waters took place previous to the fragmentation of this super continent (starting ca. 140 Ma), and that their
current distribution pattern was driven by continental drift. The distribution of the Thermosbaenacea matches precisely the
area covered by the ancient Tethys Sea or its coastlines. They are most probably relicts of a once widespread shallow-water
marine Tethyan fauna stranded in interstitial or crevicular groundwater during marine regressions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens
Freshwater Animal Diversity Assessment 相似文献
3.
4.
5.
6.
Summary
Alternaria solani, the casual organism of Early blight of potato, does not sporulate on undisturbed artificial culture media. Sporulation in P.D.A. cultures of the organism can be induced by exposing them to sun-rays for 40 minutes followed by an exposure of 60 minutes to infra-red rays. The degree of sporulation is inversely proportional to the concentration of dextrose in the medium. 相似文献
7.
8.
9.
Mycotoxins produced by seven strains ofPenicillium vulpinum (formerlyPenicillium claviforme) isolated from different sources were studied. The strains were characterized by specific profiles of secondary metabolites
and produced mycotoxins of different structural types. In addition to toxins already known for this fungal species (patulin,
roquefortine, 3,12-dihydroroquefortine, oxalin, viridicatin, cyclopenin, and α-cyclopiazonic acid), the strains studied also
produced indolyl-3-acetic acid, griseofulvin, meleagrin, and cyclopeptin. 相似文献
10.
Mycotoxins produced by seven strains of Penicillium vulpinum (formerly Penicillium claviforme) isolated from different sources were studied. The strains were characterized by specific profiles of secondary metabolites and produced mycotoxins of different structural types. In addition to toxins already known for this fungal species (patulin, roquefortine, 3,12-dihydroroquefortine, oxalin, viridicatin, cyclopenin, and alpha-cyclopiazonic acid), the strains studied also produced indolyl-3-acetic acid, griseofulvin, meleagrin, and cyclopeptin. 相似文献
11.
12.
Cumacea and Tanaidacea are marginal groups in continental waters. Although many euryhaline species from both groups are found
in estuaries and coastal lagoons, most occur only temporarily in non-marine habitats, appearing unable to form stable populations
there. A total of 21 genuinely non-marine cumaceans are known, mostly concentrated in the Ponto-Caspian region, and only four
tanaids have been reported from non-marine environments. Most non-marine cumaceans (19 species) belong in the Pseudocumatidae
and appear restricted to the Caspian Sea (with salinity up to 13‰) and its peripheral fluvial basins, including the northern,
lower salinity zones of the Black Sea (Sea of Azov). There are nine Ponto-Caspian genera, all endemic to the region. Only
two other taxa (in the family Nannastacidae) occur in areas free of any marine–water influence, in river basins in North and
South America. Both seem able to survive in waters of raised salinity of the lower reaches of these fluvial systems; but neither
has been recorded in full salinity marine environments. The only non-marine tanaidacean thus far known lives in a slightly
brackish inland spring in Northern Australia. The genus includes a second species, from a brackish-water lake at the Bismarck
Archipelago, tentatively included here as non-marine also. Two additional species of tanaidaceans have been reported from
non-marine habitats but both also occur in the sea.
Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens
Freshwater Animal Diversity Assessment 相似文献
13.
14.
A closed Lutzomyia longipalpis colony, from Ceará has been used to transmit Leishmania chagasi isolated from a fox in Pará state. The last time this colony was successfully used in similar transmission experiments was eight years (64 generations) ago indicating that this colony of Lu. longipalpis has fully maintained its vectorial capacity in spite of such a long period of maintainance in the laboratory. 相似文献
15.
Neodiaptomus schmackeri and related species are redescribed. The synonymy of this species with N. strigilipes and N. handeli is discussed. 相似文献
16.
17.
18.
Four tertiary trisomic plants are reported here, two of them (Nos. Tr11 and Tr13) from selfed progeny of a triploid Pearl millet and the other two (Nos. 3/12 and 16/7) from the progenies of radiation induced interchange heterozygotes. The extra chromosome in Tr13 and 3/12 was the nucleolus organizing chromosome. In No. 16/7 an extra chromosome enters into an association chromosomes were also involved. Meiotic behaviour in these four trisomics indicates that Tr11 and 3/12 are tertiary trisomics. It is suggested that two reciprocal translocations have occurred between two sets of chromosomes in the triploid parent and that syngamy has taken place in such a way that four interchange chromosomes and one non-interchange nucleolus organizing chromosome have come together in the offspring. The extra chromosome in No. 16/7 is an interchange chromosome which is homologous to one of the chromosomes of an interchange complex of six chromosomes. 相似文献
19.
Fish stomachs, 1149 for Tilapia zillii and 1698 for Oreochromis niloticus, were collected from April 1984 till April 1985 from a Nile canal in the Egyptian delta. Both species showed a significant
overlap of diet (Schoener's index) among individuals ranging from 12 to 17.9 cm standard length. Outside this range differences
in the importance of food of animal origin occurred. Macrophytes were the main food of O. niloticus and aquatic insects of the food of T. zillii. This initial diet overlap may have contributed to irregularity in the increase of full stomachs with increasing length,
and to a decline of the stomach index (SI = stomach weight × 100/fish weight) with increase in length in O. niloticus. The stomach of either species correlated significantly with water temperature, but with daily photoperiod in O. niloticus only. 相似文献
20.
The labella of Maxillaria acuminata Lindl., M. cerifera Barb. Rodr. and M. notylioglossa Rchb.f., all members of the M. acuminata alliance, produce a viscid wax-like secretion. Histochemical analysis revealed that the chemical composition of the secretion is similar in all three species, consisting largely of lipid and protein. Light microscopy and low-vacuum scanning electron microscopy were used to investigate the secretory process. In a fourth taxon, M. cf. notylioglossa, transmission electron microscopy showed that lipid bodies are associated with smooth endoplasmic reticulum or occur as plastoglobuli within plastids. Lipid bodies vary in appearance and this may reflect differences in chemical composition. They become associated with the plasmalemma and eventually accumulate between the latter and the cell wall. The wall contains no pits or ectodesmata, and it is speculated that lipid passes through the wall as small lipid moieties before eventually reassembling to form lipid globules on the external surface of the cuticle. These globules are able to coalesce forming extensive viscid areas on the labellum. The possible significance of this process to pollination is discussed. 相似文献