scholarly journals Spines and homologues in ‘araphid’ diatoms

2019 ◽  
Vol 152 (2) ◽  
pp. 150-162 ◽  
Author(s):  
David M. Williams
Keyword(s):  
Morphological Characters ◽  
Comparative Biology ◽  
Molecular Trees ◽  
As If

Background and aims – Many diatoms have spines on the surface of their valves. These structures differ from one taxon to another. Are all these spines the same? Are they homologues of one another? This paper sets out to explore some of the issues surrounding the determination of homologues with reference to members of Fragilariaceae. Methods – A variety of spines from species in Fragilariaceae are examined (in the SEM) and position on the valve documented relative to those already recorded in the literature. Key results – Spines that occur on the valves of some ‘araphid’ diatoms in Fragilariaceae can be interpreted in the light of where they are found. Spines that occur on the virgae can be thought of as modifications of that structure; spines that occur on the vimines can be thought of as modifications of that structure – the two kinds of spines are not homologues of each other. The term ‘spine’, on its own, is not useful for understanding taxon relationships; the term ‘spine’ is not even a character in the comparative biology sense but a descriptive catch-all for something that simply ‘sticks out from a surface’. Conclusions – Systematic characters, those applicable to comparative biology, are modifications of other characters and so are, in one sense, like taxonomies: hierarchical. A consequence of this is that plotting morphological characters on molecular trees of relationships is a futile endeavour – treating characters and their modifications, as if they are static (unit) features of a non-changing entity, is book-keeping not science.

scholarly journals Relationship Between Root and Yield Related Morphological Characters in Pea (Pisum Sativum L.)

2014 ◽  
Vol 66 (1) ◽  
pp. 3-15
Author(s):  
Sylwia Ciaglo-Androsiuk
Keyword(s):  
Root System ◽  
Morphological Traits ◽  
Lateral Roots ◽  
Morphological Characters ◽  
Yield Potential ◽  
Cultivated Plants ◽  
Genetic Determination ◽  
Canonical Correlations ◽  
Effect On Yield

AbstractRelation between morphological traits of the root system and yield related traits is an important issue concerning efforts aiming at improving of ideotype of cultivated plants species, including pea. In this paper, to analyse the dependency between traits describing the root system morphology and yield potential, Person’s andSpearman's_correlations as well as canonical correlations were used.Root system was analyzed in 14 and 21 day-old seedlings growing in blotting-paper cylinders. Yield potential of pea was analysed in a field experiment. Results of Person’s and Spearman's_correlations revealed that number of lateral roots and lateral roots density were correlated witch yield related traits. Correlation between root length and shoot length was observed only for 14 day-old seedlings. The result of canonical correlations revealed that number of lateral roots and lateral roots density had the largest effect on yield related traits. This work highlights, that in order to improve the yield of pea it might become necessary to understand genetic determination of morphological traits of the root system, especially number of lateral roots.

The Perchloric Method for the Determination of Sulfur in Rubber

1934 ◽  
Vol 7 (4) ◽  
pp. 730-735
Author(s):  
Ernest Kahane
Keyword(s):  
Nitric Acid ◽  
Perchloric Acid ◽  
Organic Substance ◽  
Present Author ◽  
General Idea ◽  
Organic Substances ◽  
Gutta Percha ◽  
Higher Temperature ◽  
As If

Abstract The problem of the determination of sulfur in rubber has been dealt with extensively in the literature, and it seems as if discussions and descriptions of new technic are nowhere nearly ended yet. The determination is so essential, and its rapid and precise execution is of such importance in industrial technic, that efforts in this direction should not be regarded as wasted. In 1926 and in 1927 Le Caoutchouc et La Gutta-Percha contained two articles in which the present author discussed the conditions of the determination of sulfur in rubber and then proposed the use of a new oxidizing mixture, not mentioned previous to that time, which involved the destruction of organic substances by perchloric acid. This method consisted simply in the attack on a 1-gram sample of rubber by 10 cc. of nitric acid (d. 1.39) and 5 cc. of perchloric acid (d. 1.61). Upon heating, attack by the nitric acid takes place, and this is followed by evaporation of the excess nitric acid, then at a little higher temperature there is an attack by the perchloric acid, which oxidizes the rest of the organic substance completely. This publication was concerned much more, in the determination of sulfur by the perchloric method, with the general idea of the destruction of organic substances than it was with the precise details of carrying it out. The technic had been studied somewhat superficially, as is shown by the text of the article itself.

Report on Australian Coccidae

1929 ◽  
Vol 20 (1) ◽  
pp. 15-37 ◽  
Author(s):  
F. Laing
Keyword(s):  
Morphological Characters ◽  
External Appearance

The following report has been drawn up mainly from collections received through the Imperial Bureau of Entomology from Messrs. C. French and G. F. Hill. I have also included some records resulting from an examination of collections made by Dr. F. R. Rodway and Mr. R. Kelly, while E. E. Green, who has always been very ready to render every assistance, very kindly turned over to me for description several species which he had under manuscript names. Figures of previously described species have been added where considered necessary ; those given by Maskell are often, it must be confessed, misleading, while those used by Froggatt in his Catalogue are illustrations mainly of the external appearance, and, though excellent in their way, are not altogether satsifactory for the critical determination of species. Leonardi in his Monograph of the genus Lepidosaphes was content, where he gave an illustration at all, with one of the pygidial fringe, but there are other characters to be found in the pygidium, and for a full appreciation and understanding of these, this area requires to be figured in entirety. The whole of the Australian Coccid fauna, so distinctive in many respects, requires to be re-examined and fresh descriptions, based on morphological characters, drawn up. Of the numerous genera erected by MacGillivray I have accepted only one in the present paper ; as he based his genera on descriptions only, I prefer to express no opinion on the standing of the others he erected until I have examined a more extensive series of species.

scholarly journals Historic income versus inflation-adjusted income in the dividend decision

1986 ◽  
Vol 17 (3) ◽  
pp. 119-124 ◽  
Author(s):  
D. P. Du Plessis ◽  
A. A. Archer ◽  
J. F. Affleck-Graves
Keyword(s):  
Research Design ◽  
Dividend Policy ◽  
Explanatory Power ◽  
Two Stage ◽  
Regression Approach ◽  
Research Findings ◽  
A Company ◽  
As If

An attempt is made to determine to what extent companies take into account the effects of inflation in formulating their dividend decisions. The research design incorporates a two-stage regression approach which permits a determination of the incremental explanatory power of collinear variables. The research findings suggest that dividend decisions are best explained in terms of historic earnings. It therefore appears as if management does not take the effects of inflation into account in formulating dividend policy. This could have serious implications for the survival of a company because it could result in a real dividend cover of less than one.

Early determination of sex in jojoba plant by CAPS assay

2010 ◽  
Vol 149 (3) ◽  
pp. 327-336 ◽  
Author(s):  
A. G. INCE ◽  
M. KARACA
Keyword(s):  
Sex Allocation ◽  
A Priori ◽  
Seed Orchard ◽  
Morphological Characters ◽  
Simmondsia Chinensis ◽  
Jojoba Oil ◽  
Dioecious Plant ◽  
Male And Female ◽  
Plant Grown

SUMMARYJojoba [Simmondsia chinensis (Link) Schneider] is a dioecious plant grown for its seeds, which are the source of liquid wax or jojoba oil. The sex of jojoba plants cannot be determined with morphological characters until the plants reach reproductive maturity at 3 or more years old. This difficulty of early sex determination imposes severe constraints in breeding studies and in the sex allocation of seedlings in seed orchard establishment, and importantly in a priori mating designs to produce superior jojoba individuals. This study reports three new cleavage-amplified polymorphic sequence (CAPS) assays, which identify male and female individuals distinctly. One of the assays could also identify hermaphrodite jojoba plants existing in nature or obtained using mutagenesis studies.

Ulva and Enteromorpha (Ulvales, Ulvophyceae, Chlorophyta) in eastern Australia: Comparison of morphological features and analyses of nuclear rDNA sequence data

1999 ◽  
Vol 12 (5) ◽  
pp. 709 ◽  
Author(s):  
Geoffrey W. Woolcott ◽  
Robert J. King
Keyword(s):  
Sequence Data ◽  
Morphological Plasticity ◽  
Morphological Characters ◽  
Australian Study ◽  
Internal Transcribed Spacer Region ◽  
Eastern Australia ◽  
Rdna Sequence Data ◽  
Ulva Australis ◽  
Potential Use

Specimens of Ulva Linnaeus and Enteromorpha Link (Ulvales, Ulvophyceae, Chlorophyta) were collected from 12 sites in eastern Australia and identified to species level on the basis of morphological characters described in the major Australian study of Womersley (1984). The species recognised were Ulva australis Areschoug, U. lactuca Linnaeus, U. fasciata Delile, Enteromorpha compressa (Linnaeus) Greville, E. flexuosa (Wulfen ex Roth) J.Agardh and E. intestinalis (Linnaeus) Link. Species placement within the genera Ulva and Enteromorpha is problematic and features of DNA were examined in order to assess their potential use as characters in species determinations. Analyses were conducted on sequence data derived from the internal transcribed spacer region ITS2, and the 5.8S gene. Groupings of the 12 isolates based on DNA analyses do not correlate with the species identified using morphology nor with the two genera. Further work is required before authoritative conclusions can be reached regarding the significance of morphological plasticity in determination of differences within and between Ulva and Enteromorpha species; nevertheless, DNA studies may provide a backbone of characters upon which to base such a study.

scholarly journals VI. On the determination of a ship’s place from observations of altitude

1871 ◽  
Vol 19 (123-129) ◽  
pp. 259-266 ◽  
Keyword(s):  
As If

The ingenious and excellent idea of calculating the longitude from two different assumed latitudes with one altitude, marking off on a chart the points thus found, drawing a line through them, and concluding that the ship was somewhere on that line at the time of the observation, is due to Captain T. H. Sumner. It is now well known to practical navigators. It is described in good books on navigation, as, for instance, Raper’s (§§ 1009-1014). Were it not for the additional trouble of calculating a second triangle, this method ought to be universally used, instead of the ordinary practice of calculating a single position, with the most probable latitude taken as if it were the true latitude.

scholarly journals SEX DETERMINATION OF BALI STARLING (Leucopsar rothschildi) USING MOLECULAR SEXING

2015 ◽  
Vol 2 (1) ◽  
pp. 114
Author(s):  
Putu Indra Pramana Wirastika ◽  
Ignatius Pramana Yuda ◽  
Felicia Zahida
Keyword(s):  
Dna Binding ◽  
Sex Determination ◽  
Gel Electrophoresis ◽  
Morphological Characters ◽  
Molecular Sexing ◽  
Agarose Gel ◽  
Agarose Gel Electrophoresis ◽  
Pcr Products ◽  
Conventional Methods

<p>Bali Starling (Leucopsar rothschildi) are monomorphic at the age of nestling. For the conservation of bird it important is to determine its sex at the earlier stage. Conventional methods have limitations. This study applied PCR-based molecular sexing to answer this issue. This study aimed to obtain the most effective molecular primers to identify the sex of Bali starling. The most common used combination of P2/P8, 2550F/ 2718R and 1237L/1272H primers, which amplify CHD1 gene (Chromo-helicase-DNA-binding) were evaluated. DNA samples were obtained from secondary wing feathers of young Bali Starling. Separation in agarose gel electrophoresis of PCR products showed that the three primers were successfully amplified the samples with different degrees of success, that was 90% (P2/P8), 86.7% (2550F/2718R), and 73.3% (1237L/1272H), respectively. However, only the combination of P2/P4 and 2550F/2718R primers was able to sex Bali Starling based on observation of PCR products on agarose gel. The sizes of the genes were slightly different with those reported on previous studies. Most of the results of molecular sexing were in accordance with the sex based on morphological characters.</p><p><br /><strong>Keywords</strong> : Bali starling, Leucopsar rothschildi, molecular sexing, CHD gene</p>

Phylogenetic revision of the shrimp genera Ephyrina, Meningodora and Notostomus (Acanthephyridae: Caridea)

2020 ◽  
Author(s):  
Anastasiia A Lunina ◽  
Dmitry N Kulagin ◽  
Alexander L Vereshchaka
Keyword(s):  
Molecular Markers ◽  
Morphological Characters ◽  
Valid Species ◽  
Phylogenetic Study ◽  
Forward Motion ◽  
Molecular Analyses ◽  
Phylogenetic Revision ◽  
Molecular Trees

Abstract The shrimp genera Ephyrina, Meningodora and Notostomus have an unusual carapace strengthened with carinae and a half-serrated mandible, which may suggest a possible monophyly of this group. Here we test this hypothesis and present the first phylogenetic study of these genera based on 95 morphological characters (all valid species coded) and six molecular markers (71% of valid species sequenced). Representatives of all genera of Oplophoridae (sister to Acanthephyridae) were outgroups, 32 species belonging to all genera and potentially different clades of Acanthephyridae were ingroups. Both morphological and molecular analyses retrieve trees with similar topology. Our results reject the hypothesis of a clade formed by Ephyrina + Meningodora + Notostomus. We show that Ephyrina and Notostomus are monophyletic, both on morphological and on molecular trees, Meningodora gains support only on morphological trees. Evolutionary traits in the Ephyrina and Meningodora + Notostomus clades are different. Synapomorphies are mostly linked to adaptations to forward motion in Ephyrina (oar-like meri and ischia of pereopods, stempost-like rostrum) and to progressive strengthening of the carapace and pleon in Meningodora and Notostomus (net of sharp carinae). Unusual mandibles evolved in the clades independently and represent convergent adaptations to feeding on gelatinous organisms.

Determination of mitochondrial DNA haplotypes from sting remnants of the honeybee Apis mellifera (Hymenoptera:Apidae)

1994 ◽  
Vol 84 (4) ◽  
pp. 551-554 ◽  
Author(s):  
W.S. Sheppard ◽  
M.C. Arias ◽  
H. Shimanuki
Keyword(s):  
Morphological Characters ◽  
European Ancestry ◽  
Defensive Behaviour ◽  
Haplotype Data ◽  
The Usa ◽  
Baseline Information ◽  
One Year ◽  
Africanized Honeybees ◽  
Mtdna Haplotype

AbstractAfricanized honeybees are presently expanding their geographic range within the USA and are considered undesirable due to their substantial defensive behaviour. Africanized honeybees can be differentiated from honeybees of European ancestry using discriminant analysis of morphological characters, based on a minimum of ten intact specimens per colony. In this paper we report a PCR-based method suitable for the identification of African or European mtDNA from sting remnants, such as typically remain on victims following a stinging incident. We experimentally simulated collection and shipment conditions with dried and alcohol preservation of stings, and also report that the method was suitable for sting remnants stored with a victim sample for over one year in alcohol. The determination of mtDNA haplotypes from stinger remnants must be tempered by the constraints inherent in interpretation of mtDNA haplotype data. Such data do not provide any information regarding the genetic contribution of the paternal lineage. However, in geographic areas where baseline information regarding European haplotype frequencies is known, the detection of a different mtDNA haplotype in stingers from a victim, especially when associated with observations of extreme defensive behaviour, would certainly be suggestive of Africanization.

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