Organo arsenicals - aryl sulphonyl esters of hydrophenyl arsonic acids

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‘It Takes Two Hands to Clap’: How Gaddi Shepherds in the Indian Himalayas Negotiate Access to Grazing

This article examines the effects of state intervention on the workings of informal institutions that coordinate the communal use and management of natural resources. Specifically it focuses on the case of the nomadic Gaddi shepherds and official attempts to regulate their access to grazing pastures in the Indian Himalayas. It is often predicted that the increased presence of the modern state critically undermines locally appropriate and community-based resource management arrangements. Drawing on the work of Pauline Peters and Francis Cleaver, I identify key instances of socially embedded ‘common’ management institutions and explain the evolution of these arrangements through dynamic interactions between individuals, communities and the agents of the state. Through describing the ‘living space’ of Gaddi shepherds across the annual cycle of nomadic migration with their flocks I explore the ways in which they have been able to creatively reinterpret external interventions, and suggest how contemporary arrangements for accessing pasture at different moments of the annual cycle involve complex combinations of the formal and the informal, the ‘traditional’ and the ‘modern’

New Exact Solutions of a Generalized Shallow Water Wave Equation

In this work an extended elliptic function method is proposed and applied to the generalized shallow water wave equation. We systematically investigate to classify new exact travelling wave solutions expressible in terms of quasi-periodic elliptic integral function and doubly-periodic Jacobian elliptic functions. The derived new solutions include rational, periodic, singular and solitary wave solutions. An interesting comparison with the canonical procedure is provided. In some cases the obtained elliptic solution has singularity at certain region in the whole space. For such solutions we have computed the effective region where the obtained solution is free from such a singularity.Comment: A discussion about singularity and some references are added. To appear in Physica Script

Phytophthora nicotianae diseases worldwide: new knowledge of a long-recognised pathogen

Phytophthora nicotianae was first isolated from tobacco at the end of the 19th century. This organism is now considered as one of the most devastating oomycete plant pathogens, with a recognized host range of more than 255 species over five continents and a wide diversity of climates. The economic losses caused by P. nicotianae are difficult to estimate, because of the diversity of its hosts and ecological niches. For these reasons, this pathogen represents a continuous challenge to plant disease management programmes, which frequently rely solely on the use of chemicals. Phytophthora nicotianae is better adapted than its competitors to abiotic stresses, especially to climate warming. As a result, its importance is increasing. This review illustrates, with some examples, how P. nicotianae currently impacts plant economies worldwide, and how it may constitute more severe threats to agriculture and natural ecosystems in the context of global climate change

The makeshift city: towards a global geography of squatting

This paper introduces a set of analytical frames that explore the possibilities of conceiving, researching and writing a global geography of squatting. The paper argues that it is possible to detect, in the most tenuous of urban settings, ways of thinking about and living urban life that have the potential to reanimate the city as a key site of geographical inquiry. The paper develops a modest theory of ‘urban combats’ to account for the complexity and provisionality of squatting as an informal set of practices, as a makeshift approach to housing and as a precarious form of inhabiting the city

Inhibitors of Helicobacter pylori Protease HtrA Found by ‘Virtual Ligand’ Screening Combat Bacterial Invasion of Epithelia

Background: The human pathogen Helicobacter pylori (H. pylori) is a main cause for gastric inflammation and cancer. Increasing bacterial resistance against antibiotics demands for innovative strategies for therapeutic intervention. Methodology/Principal Findings: We present a method for structure-based virtual screening that is based on the comprehensive prediction of ligand binding sites on a protein model and automated construction of a ligand-receptor interaction map. Pharmacophoric features of the map are clustered and transformed in a correlation vector (‘virtual ligand’) for rapid virtual screening of compound databases. This computer-based technique was validated for 18 different targets of pharmaceutical interest in a retrospective screening experiment. Prospective screening for inhibitory agents was performed for the protease HtrA from the human pathogen H. pylori using a homology model of the target protein. Among 22 tested compounds six block E-cadherin cleavage by HtrA in vitro and result in reduced scattering and wound healing of gastric epithelial cells, thereby preventing bacterial infiltration of the epithelium. Conclusions/Significance: This study demonstrates that receptor-based virtual screening with a permissive (‘fuzzy’) pharmacophore model can help identify small bioactive agents for combating bacterial infection

Molecular cytogenetics (FISH, GISH) of Coccinia grandis: A ca. 3 myr-old species of Cucurbitaceae with the largest Y/autosome divergence in flowering plants

The independent evolution of heteromorphic sex chromosomes in 19 species from 4 families of flowering plants permits studying X/Y divergence after the initial recombination suppression. Here, we document autosome/Y divergence in the tropical Cucurbitaceae Coccinia grandis, which is ca. 3 myr old. Karyotyping and C-value measurements show that the C. grandis Y chromosome has twice the size of any of the other chromosomes, with a male/female C-value difference of 0.094 pg or 10% of the total genome. FISH staining revealed 5S and 45S rDNA sites on autosomes but not on the Y chromosome, making it unlikely that rDNA contributed to the elongation of the Y chromosome; recent end-to-end fusion also seems unlikely given the lack of interstitial telomeric signals. GISH with different concentrations of female blocking DNA detected a possible pseudo-autosomal region on the Y chromosome, and C-banding suggests that the entire Y chromosome in C. grandis is heterochromatic. During meiosis, there is an end-to-end connection between the X and the Y chromosome, but the X does not otherwise differ from the remaining chromosomes. These findings and a review of plants with heteromorphic sex chromosomes reveal no relationship between species age and degree of sex chromosome dimorphism. Its relatively small genome size (0.943 pg/2C in males), large Y chromosome, and phylogenetic proximity to the fully sequenced Cucumis sativus make C. grandis a promising model to study sex chromosome evolution. Copyright © 2012 S. Karger AG, Base