Non trivial examples of coupled equations for K\"ahler metrics and Yang-Mills connections

We provide non trivial examples of solutions to the system of coupled equations introduced by M. Garc\'ia-Fern\'andez for the uniformization problem of a triple $(M,L,E)$ where $E$ is a holomorphic vector bundle over a polarized complex manifold $(M,L)$, generalizing the notions of both constant scalar curvature K\"ahler metric and Hermitian-Einstein metric.Comment: 17 page

Keanekaragaman Jenis Tumbuhan Paku-pakuan (Pteridophyta) di Desa Bemban Kawasan Hutan Lindung Gunung Ambawang Kecamatan Kubu Kabupaten Kubu Raya

Research on Fern Diversity (Pteridophyta) In Bemban village In Mount Ambawang Protected Forest Kubu Kubu Raya District of West Kalimantan Province was held on September 16 th to October 7 th , 2013. Sampling plot was taken purposive where there were many fern found. There were four sampling plot based on height. Plot I located in 50-150 m above sea level altitude, plot II in 150-250 m above sea level altitude, plot III in 250-350 m above sea level altitude,and plot IV in 50-150 m above sea level altitude (rubber plantations). Each sampling plot 40 m x 40 m, divided into 160 subplot 2 m x 5 m aech. There were 13 fern species with 4162 individual these species consist of 8 terresterial fern with 3799 individual, and 5 epiphytic fern with 813 individuals. The plot at altitude of 50-150 m,were dominated by Lygodium circinatum and Asplenium nidus, altitude 150-250 m were dominated by Acrostichum spesiocum and Asplenium nidus, altitude 250-350 m dominated by Selaginella wildenowii, Asplenium longisimmum height of 50-150 m asl (rubber plantation) dominated by Nephrolepis biserrata and Asplenium nidus. The highest diversity index value was at altitude 150-250 m (2,043) which means the species diversity of ferns were low. Similarity index was highest between altitude 250-350 m and altitde 50-150 m in rubber plantation,in the value 5,638 %. It means between thw different plot there is no similarity (¤ 25 %). Keywords: Ferns, biodiversity, forest protected mount Ambaw

Keanekaragaman Tumbuhan Paku Terestrial Di Hutan Kota DKI Jakarta [Terestrial Ferns Diversity in Urban Forest DKI Jakarta]

Urban forest is one of the green open area consisted of natural forest-like vegetation. It has suitable microclimate for understory habitat, including terrestrial ferns. The diversity of fern in three urban forest in DKI Jakarta is reported, i.e the urban forest at The University of Indonesia (UI) Campus, The Cibubur Arboretum and PT JIEP (Jakarta Industrial Estate Pulogadung). Vegetation analysis was conducted by purposive sampling method with a transect line of 200 m in each location with 15 plots of (3x3) m2 each. Fern determination was done based on herbarium specimens and literatures. Fern diversity was analyzed based on Shannon diversity index, and equality index. Canonical correspondence analysis (CCA) was performed to determine the correlation between fern diversity and abiotic factors. There were 18 fern species classified into 11 genera and eight families, at the UI urban forest and Cibubur Arboretum, but there was no fern in PT JIEP. Fern with the highest importance value index was Sphaerostephanos sp. (161.33%) in The UI urban forest, and Lygodium microphyllum (Cav.) R.Br. (71.63%) in Cibubur Arboretum. The CCA result showed that the fern diversity correlated to four abiotic factors i.e temperature,humidity, light intensity and soil pH

Quercetin elevates p27Kip1 and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1

Our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 and G2/M, in correlation with p53 activation. The expression of bovine papillomavirus type 4 (BPV-4) E7 overcame this arrest and lead to the development of tumorigenic cells lines (Beniston et al., 2001). Given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointestinal (GI) tract in humans, we investigated whether a similar situation would occur in human cells transformed by human papillomavirus type 16 (HPV-16) oncoproteins. Quercetin arrested primary human foreskin keratinocytes in G1. Arrest was linked to an elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the HPV16 E6 and E7 oncoproteins in transformed cells failed to abrogate cell cycle arrest. G1 arrest in the transformed cells was also linked to an increase of p27Kip1 with a concomitant reduction of cyclin E-associated kinase activity. This elevation of p27Kip1 was due not only to increased protein half-life, but also to increased mRNA transcription

Fine-scale fern ecological responses inform on riparian forest habitat conservation status

The recognition of the ecological quality of ecosystems and habitats therein is increasingly important in the Anthropocene. However, there are still scarcely explored ways of how and what to assess to obtain a sound ecological status of habitats. Ferns are an understudied plant group, especially given their usefulness as ecological indicators. Disentangling biotic and abiotic factors that drive fine-scale fern distribution could provide insight into the quality of their habitats. We investigated the environmental factors affecting the distribution of different largely distributed fern species in Europe. We studied their presence and abundance at different life stages in a forest habitat of European priority conservation concern. Our aim was to understand whether fern species can be used as an ecological indicator group in riparian alderwood habitat. We sampled 120 plots of 50 m(2) in randomly selected transects along streams of a riparian forest habitat characterized by the presence of many fern species in the understory, controlling for the effects of geology and elevation. Within each plot, fern species were recorded, including vegetative and generative stages of each ramet (rosette of fronds). We modelled fern occurrence and abundance for the different fern life stages, and diversity indices of the fern community in relation to environmental predictors. We found that population- and community-level responses of ferns mainly depended on soil granulometry and, to a lesser extent, moss cover and stream orientation. We also found that the generative life stage compared to the vegetative adult stage benefits from different ecological characteristics for certain fern species. Alterations of the natural hydrology might lead to a general deterioration in habitat quality for ferns. We suggest that some fern species acting as early-warning species, and potentially their life stages, can be used as an ecological quality indicator for riparian forest habitats. This study deepened the understanding of the fine-scale ecology of an array of European ferns in riparian forests and provides valuable information to assist in the conservation of fern species and their populations

Propagation, taxonomy and ecophysiological characteristics of the Azolla-Anabaena symbiosis in freshwater habitats of Beni-Suef Governorate (Egypt).

A new ecotype of Azolla fern has established in freshwater habitats at Beni-Suef Governorate. The fern propagates in shallow irrigation canals and drains with low-velocity water. Azolla fern is circular (fan-like) in shape with a diameter of 2-3 cm; the surface of the fronds is covered with trichomes and contains stomata with annular guard cells and central pores. Azolla is a sterile hybrid, only forming microsporocarps, never megasporocarps: the microsporocarp contains about 64 microsporangia. Each microsporangium consists of 4 massula, each characterized by the presence of anchor-like multiseptate glochidia covering the whole surface of the massula. This ecotype probably belongs to Azolla caroliniana on the basis of vegetative and reproductive characteristics. Growth (biomass yield) is seasonal, with higher biomass (3.0-4.5 kg m-2) and shorter doubling time in summer, reducing to about 1.0-1.5 kg m-2 in winter. Azolla plants accumulated the minerals Fe, Zn, Cu, Ni and Pb when growing in freshwater canals, drains and waste water. Salt stress treatment inhibited growth, nitrogen fixation and protein content. Iinhibitory levels of salinity were about 0.6-0.8 % NaCl. Growth and nitrogen fixation were inhibited at higher levels (2.4 mol m-3 and 5.1 mol m-3) of combined nitrogen (ammonium sulphate and urea). The ecophysiological significance of Azolla in the freshwater habitats of Beni-Suef Governorate is discussed

On the eigenvalues of some nonhermitian oscillators

We consider a class of one-dimensional nonhermitian oscillators and discuss the relationship between the real eigenvalues of PT-symmetric oscillators and the resonances obtained by different authors. We also show the relationship between the strong-coupling expansions for the eigenvalues of those oscillators. Comparison of the results of the complex rotation and the Riccati-Pad\'{e} methods reveals that the optimal rotation angle converts the oscillator into either a PT-symmetric or an Hermitian one. In addition to the real positive eigenvalues the PT-symmetric oscillators exhibit real positive resonances under different boundary conditions. They can be calculated by means of the straightforward diagonalization method. The Riccati-Pad\'e method yields not only the resonances of the nonhermitian oscillators but also the eigenvalues of the PT-symmetric ones