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Number of results: 6
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Abstract

Here we use synchrotron tomography to characterise dental vasculature in the oldest known tooth-bearing

sharks, Leonodus carlsi Mader, 1986 and Celtiberina maderi Wang, 1993. Three dimensional reconstruction

of the vascular system and microstructure of both taxa revealed a complex and dense network of canals, including

horizontal, ascending and secondary bifurcated canals, as well as histological features consistent with

an osteodont histotype. However, L. carlsi and C. maderi also exhibit significant morphological differences,

showing Leonodus a typical diplodont tooth morphology with a linguo-labially elongated base, that contrast

with Celtiberina’s teeth that show a single conical cusp curved lingually with a week developed flat base mesio-

distally extended, perhaps reflecting distant relationship. These data are compatible with a pre-Devonian

diversification of the two main tooth types traditionally recognised in Palaeozoic sharks (i.e., “cladodont” vs

“diplodont”). Finally, our data demonstrate that existing dental classification schemes based on styles of vascularisation

are over-simplified, especially when Palaeozoic taxa are considered.

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Authors and Affiliations

Carlos Martínez-Pérez
Alba Martín-Lazaro
Humberto G. Ferrón
Martina Kirstein
Philip C.J. Donoghue
Hector Botella
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Abstract

The paper presents plant communities from northern Wedel Jarlsberg Land. 55 species of vascular plants were described in this region. Differentiation of plant communities is discussed as controlled by habitat conditions. Plant succession in intramorainal zones of Renardbreen and Scottbreen has been also considered.

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Authors and Affiliations

Anna Rzętkowska
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Abstract

In Cameroon, oil palm ( Elaeis guineensis Jacq.) is of economic importance. However, it is affected by vascular wilt presumed to be caused by Fusarium oxysporum f. sp. elaeidis (FOE). Accurate species identification requires molecular-based comparisons. The aim of this work was to molecularly identify Fusarium species associated with diseased oil palms and to determine the pathogenicity of selected isolates. Fungal samples of diseased palms were collected from the canopies and the soil of five oil palm estates of the Cameroon Development Corporation and characterized by sequencing and comparing the translation elongation factor 1a gene. The results revealed the presence of FOE from approximately 80% of the isolates. Cameroonian isolate within FOE clade 1 exhibited the greatest variability grouping with isolates from Suriname, Brazil and Democratic Republic of Congo. Other isolates found in FOE clade 2 formed a unique group which was comprised solely of isolates originating from Cameroon. Twenty-two isolates were chosen for pathogenicity tests. After a short time, 14 isolates were found to be pathogenic to oil palm seedlings. This study revealed the pathogenicity of FOE isolates from Cameroon and demonstrated that FOE in Africa is more diverse than previously reported, including a lineage not previously observed outside of Cameroon. Comparisons between all isolates will ultimately aid to devise appropriate control mechanisms and better pathogen detection methods.
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Authors and Affiliations

Rosemary Tonjock Kinge
1
ORCID: ORCID
Lilian Moforcha Zemenjuh
2
Evelyn Manju Bi
3
Godswill Ntsomboh-Ntsefong
4
Grace Mbong Annih
5
Eneke Esoeyang Tambe Bechem
2

  1. Department of Plant Sciences, Faculty of Science, University of Bamenda, Bamenda, Northwest Region, Cameroon
  2. Department of Plant Science, Faculty of Science, University of Buea, Buea, Southwest Region, Cameroon
  3. Department of Crop Production Technology, College of Technology, University of Bamenda, Bamenda, Northwest Region, Cameroon
  4. Department of Plant Biology, Faculty of Science, University of Yaounde 1, Yaounde, Center Region, Cameroon
  5. Department of Plant Biology, Faculty of Science, University of Dschang, Dschang, West Region, Cameroon
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Abstract

In this paper a review on biometric person identification has been discussed using features from retinal fundus image. Retina recognition is claimed to be the best person identification method among the biometric recognition systems as the retina is practically impossible to forge. It is found to be most stable, reliable and most secure among all other biometric systems. Retina inherits the property of uniqueness and stability. The features used in the recognition process are either blood vessel features or non-blood vessel features. But the vascular pattern is the most prominent feature utilized by most of the researchers for retina based person identification. Processes involved in this authentication system include pre-processing, feature extraction and feature matching. Bifurcation and crossover points are widely used features among the blood vessel features. Non-blood vessel features include luminance, contrast, and corner points etc. This paper summarizes and compares the different retina based authentication system. Researchers have used publicly available databases such as DRIVE, STARE, VARIA, RIDB, ARIA, AFIO, DRIDB, and SiMES for testing their methods. Various quantitative measures such as accuracy, recognition rate, false rejection rate, false acceptance rate, and equal error rate are used to evaluate the performance of different algorithms. DRIVE database provides 100% recognition for most of the methods. Rest of the database the accuracy of recognition is more than 90%.

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Authors and Affiliations

Poonguzhali Elangovan
Malaya Kumar Nath
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Abstract

This study investigated the details of the morphological and anatomical structure of the generative organs of the Subantarctic flowering plant, belonging to the family Caryophyllaceae - Colobanthus apetalus (Labill.) Druce. The research material was collected in hostile natural conditions in Subantarctic regions, and also was grown in the incubators and the greenhouse of the University of Warmia and Mazury in Olsztyn (Poland). C. apetalus forms tufts with soft and grassy leaves and small greenish flowers that are more obvious than in other Colobanthus species. C. apetalus forms open (chasmogamic) flowers in greenhouse cultivation. The flowers most often form five stamens with two microsporangia. Over a dozen pollen grains are formed in each microsporangium. Studies of the plant material originated from natural conditions conducted by means of a light microscope, have shown that the ovules of the analyzed representative of the genus Colobanthus are anatropous, crassinucellar, and the monosporic embryo sac develops according to the Polygonum type (the most common type in angiosperms). C. apetalus plants underwent a full development cycle in greenhouse cultivation and produced fertile, perispermic seeds. During the C. apetalus growth in conditions at increased air humidity, the vivipary was also observed.
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Authors and Affiliations

Sylwia Milarska
1
ORCID: ORCID
Piotr Androsiuk
1
ORCID: ORCID
Irena Giełwanowska
1
ORCID: ORCID

  1. Department of Plant Physiology, Genetics and Biotechnology, University of Warmia and Mazury in Olsztyn, Poland
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Abstract

Spectroscopy has become one of the most used non-invasive methods to detect plant diseases before symptoms are visible. In this study it was possible to characterize the spectral variation in leaves of Solanum lycopersicum L. infected with Fusarium oxysporum during the incubation period. It was also possible to identify the relevant specific wavelengths in the range of 380–1000 nm that can be used as spectral signatures for the detection and discrimination of vascular wilt in S. lycopersicum. It was observed that inoculated tomato plants increased their reflectance in the visible range (Vis) and decreased slowly in the near infrared range (NIR) measured during incubation, showing marked differences with plants subjected to water stress in the Vis/NIR. Additionally, three ranges were found in the spectrum related to infection by F. oxysporum (510–520 nm, 650–670 nm, 700–750 nm). Linear discriminant models on spectral reflectance data were able to differentiate between tomato varieties inoculated with F. oxysporum from healthy ones with accuracies higher than 70% 9 days after inoculation. The results showed the potential of reflectance spectroscopy to discriminate plants inoculated with F. oxysporum from healthy ones as well as those subjected to water stress in the incubation period of the disease.

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Authors and Affiliations

Juan Carlos Marín Ortiz
Lilliana María Hoyos Carvajal
Veronica Botero Fernandez

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