59 research outputs found
Genetic difference and resemblance between Acipenser persicus and Acipenser gueldenstaedtii by means of RAPD Technique
We studied genetic difference and resemblance between Acipenser persicus and Acipenser guldenstaediii using Random Amplified Polymorphic DNA (RAPD) technique. The DNA of tail fin tissue of three A. persicus and A. gueldenstaedtii were extracted using phenol-chloroform method. After electrophoresis of the samples by agarose gel, their concentrations were regulated and Polymerise Chain Reaction (PCR) was conducted by 53 primers. PCR products were electrophoresed on polyacrylamide gel and silver staining was done to reveal the DNA bands of the samples. Among 53 primers, 17 had no site on genomic DNA of A. persicus and A. gueldenstaedtii and did not produce any bands while the remaining 36 primers showed band pattern. Analyzing the PCR products data using RAPD PLOT program showed that the maximum and minimum genetic distance between species were 73% and 65% respectively. Also, the mean difference between the species was 70% and the maximum and minimum genetic resemblance between the two species were 35% and 27% respectively. Based on the results, we conclude that A. persicus is an independent species from A. gueticienstaeditii
Two New Species of the Genus Eurytoma (Hymenoptera, Eurytomidae) from Iran
Описаны два новых вида хальцидоидных наездников из Ирана: Eurytoma iranica Zerova, sp. n. (типовая местность: Иран, Сержен) и E. ghazvini Zerova, sp. n. (типовая местность: Иран, пров. Гезвин).Eurytoma iranica Zerova, sp. n. (type locality: Sirjan, Iran) and Eurytoma ghaznvini Zerova, sp. n. (type locality: Ghazvin prov., Iran) are described
A conformal, dynamic pattern-reconfigurable antenna using conductive textile-polymer composite
A conformal antenna with electronically tuning capability of its radiation pattern between broadside and monopole-like patterns is proposed. The antenna is based on a proximity-fed circular patch, loaded with a ring patch and four rectangular slots. The design is planar without any use of rigid shorting posts or complex feeding network. The reconfigurability is achieved by activating and deactivating the slots using PIN diodes, to switch between TM02 (monopole-like mode) and perturbed TM02 distributions (broadside mode) of the antenna. For conformability, the antenna is fabricated using highly flexible PDMS-conductive fabric composite. All the antenna parts, including the RF switches, wires, and DC biasing circuit are fully encapsulated by PDMS to provide resilience against deformation and harsh environment. Investigations on the RF performance and mechanical stability of the antenna were conducted. Under various bendings, it was demonstrated that all the antenna components, including those for electronic switching, remained intact and in working order even under radius bending of 30 mm, thus maintaining good pattern reconfigurability and overall performance. When bent, the measured results at 5.2 GHz show a stable radiation performance relative to those of the flat case (i.e., maximum gain of 2.9 dBi and efficiency of 64% in broadside mode, corresponding to 1.75 dBi and 52% in monopole-like mode). To the best of our knowledge, all these features have never been demonstrated in previously published pattern reconfigurable antennas
The systematic study of the influence of neutron excess on the fusion cross sections using different proximity-type potentials
Using different types of proximity potentials, we have examined the trend of
variations of barrier characteristics (barrier height and its position) as well
as fusion cross sections for 50 isotopic systems including various collisions
of C, O, Mg, Si, S, Ca, Ar, Ti and Ni nuclei with condition
for compound systems. The results of our studies reveal that the relationships
between increase of barrier positions and decrease of barrier heights are both
linear with increase of ratio. Moreover, fusion cross sections also
enhance linearly with increase of this ratio.Comment: 28 pages, 7 figures, 5 Table
The relationship between local structure and photo-Fenton catalytic ability of glasses and glass-ceramics prepared from Japanese slag
Local structure and the photo-Fenton reactivity of iron-containing glasses and glass-ceramics prepared from Japanese domestic waste slag were investigated. The largest rate constant (k) of (2.8 ± 0.08) × 10−2 min−1 was recorded for the methylene blue degradation test by using H2O2 with a heat-treated ‘model slag’. The 57Fe Mössbauer spectrum was composed of a paramagnetic doublet with isomer shift of 0.18 ± 0.01 mm s−1 attributed to distorted FeIIIO4 tetrahedra. These results indicate that the paramagnetic Fe3+ provided strong photo-Fenton catalytic ability, and that waste slag can thus be recycled as an effective visible-light activated photocatalyst
What can whiskers tell us about mammalian evolution, behaviour, and ecology?
Most mammals have whiskers; however, nearly everything we know about whiskers derives from just a handful of species, including laboratory rats Rattus norvegicus and mice Mus musculus, as well as some species of pinniped and marsupial. We explore the extent to which the knowledge of the whisker system from a handful of species applies to mammals generally. This will help us understand whisker evolution and function, in order to gain more insights into mammalian behaviour and ecology. This review is structured around Tinbergen’s four questions, since this method is an established, comprehensive, and logical approach to studying behaviour. We ask: how do whiskers work, develop, and evolve? And what are they for? While whiskers are all slender, curved, tapered, keratinised hairs that transmit vibrotactile information, we show that there are marked differences between species with respect to whisker arrangement, numbers, length, musculature, development, and growth cycles. The conservation of form and a common muscle architecture in mammals suggests that early mammals had whiskers. Whiskers may have been functional even in therapsids. However, certain extant mammalian species are equipped with especially long and sensitive whiskers, in particular nocturnal, arboreal species, and aquatic species, which live in complex environments and hunt moving prey. Knowledge of whiskers and whisker use can guide us in developing conservation protocols and designing enriched enclosures for captive mammals. We suggest that further comparative studies, embracing a wider variety of mammalian species, are required before one can make large-scale predictions relating to evolution and function of whiskers. More research is needed to develop robust techniques to enhance the welfare and conservation of mammals
- …