The phylogenetic relationships of flying squirrels (Pteromyinae) were studied by obtaining complete sequence data from the mitochondrial cytochrome b gene of eight Old World and two New World flying squirrel species, with special reference to the systematic and phylogenetic status among Hylopetes fimbriatus (Gray, 1837) (≡ Eoglaucomys fimbriatus (Gray, 1837)) from Pakistan, two Glaucomys Thomas, 1908 species from North America, and two Hylopetes Thomas, 1908 species from Southeast Asia. Phylogenetic trees supported clustering of (i) Belomys pearsonii (Gray, 1842), (ii) H. fimbriatus, the Glaucomys species, Hylopetes lepidus (Horsfield, 1823), and Hylopetes phayrei (Blyth, 1859), (iii) species of Pteromys G. Cuvier, 1800, and (iv) species of Petaurista Link, 1795. Early polytomic divergence among the flying squirrel genera could have taken place in the northern part of the Eurasian continent. The unclear divergence between the Old and New World flying squirrels shows that divergence among flying squirrel genera could have occurred before the formation of the Bering Strait. Hylopetes fimbriatus was more closely related to the two Glaucomys species than to H. lepidus or H. phayrei, supporting placement of the species fimbriatus in the monotypic genus Eoglaucomys Howell, 1915.
Infrared-triggered remote cameras were used on a 24-h observation of fruit consumption by vertebrates on the forest floor in the Pasoh Forest Reserve, Negeri Sembilan, Peninsular Malaysia, from July 1993 to May 1995. There were two peaks of flowering, in February-April and October. Fruiting showed less seasonality than flowering and fluctuated from year to year. Nearly 4000 photos of animals were obtained and 34 animal species were identified. The 16 most dominant frugivorous species were analysed: 13 species of mammal, two species of bird and one species of reptiles. The pig-tailed macaque (Macaca nemestrina) was the most common visitor, using 44 out of 49 plat species. Six edible parts from five fruit species (Pithecellobium bubalium, Garcinia nervosa, Knema hookeriana, Myristica cinnamomea and M. elliptica) of the porcupine (Trichys fasciculata)-favoured fruits and other fruits consumed by other animals were analysed for nutrient content. Nutrient contents varied widely among fruits: moisture 8.8-90.5%, protein 1.6-13.6%, lipid 0.03-55.0% and NFE 0.8-52.0% on a fresh matter basis. The gross energy was estimated in the range of 1.8-28.7 kJ/g. The porcupine-favoured fruits were rich in nutrients and energy. No frugivore showed a significant preference for either green or coloured fruits.
The development of optical fibers from attenuation and absorption of fiber material for efficiency and quality has produced several positive results. However, several natural negative factors and environmental errors cause problems such as birefringence and dispersion mode variations. This article therefore proposed a simulation of birefringence and polarization mode dispersion (PMD) to investigate the emergence of interference and efforts towards finding a solution to the problem of optical fiber. Moreover, a single-mode fiber was investigated at the core refractive index and cladded with a core radius and fixed sample for a wavelength of infrared regimes. The performance of fibers was also evaluated through the determination of the PMD value of the fibers. The simulation results showed the difference observed in birefringence produced the power affecting the output. Meanwhile, the PMD also produced the light waves discovered to be experiencing widening pulses in the cladding.
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