406 research outputs found

    Tsunami disaster 2004: lessons from resettlement

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    The tsunami disaster of 26 December 2004 killed over 30,000 people, displaced 1,000,000 persons and affected over two thirds of the island’s coastline lying in 12 districts. Besides the loss of life and injuries, the tsunami caused extensive damage to infrastructure and property and disruptions of fisheries and other livelihood activities and business assets. After the emergency repairs were attended the government has entered into the phase of rehabilitation and reconstruction of national infrastructure in the affected areas with the assistance of many development partners. However, the national construction industry has not been able to cater to the demand or need of tsunami reconstruction work. Further challenges include procurement delays, ensuring environmental safeguards, security concerns in the uncleared areas and capacity constraints. As far as the new settlements for the beneficiaries are concerned, development of infrastructure such as water, electricity and internal roads remain the biggest challenge to the government

    Priority for agriculture over housing, water supply and sanitation of Mahaweli settlers

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    The Mahaweli Ganga Development Scheme (MGDS) has been the largest multipurpose development project ever implemented in Sri Lanka, using the water resources of the river Mahaweli and related adjacent river basins. Of the thirteen independent development areas identified for integrated development and human settlement, System – H, System –B, System- C, System-G and System-L are either fully or partly developed and operational. The uses of water such as irrigation, power generation and domestic consumption are inter-linked within a basin. As both the quality and quantity of water available for downstream users depend on the activities of the upstream users. However, during the last three decades, the emphasis has been to increase crop production and productivity of land and water, over the development of essential infrastructure. This trend has been so established in agriculture based settlement projects, even the international funding agencies do not attach much importance to the provision or improvement of infrastructure facilities

    A Book Review: Sustainable Human Resource Management by Senior Prof. Dr. Henarath H.D.N.P. Opatha

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    There is a growing awareness and enthusiasm on people management in Sri Lankan organizations. This is evident by the increasing number of activities related to Human Resource Management (HRM) in many fronts taking place in the island. Yet, we have a long way to go in unleashing the true potential of our productive workforce, in the wake of a post-war economic expansion and development drive. One key element in such an endeavor is to have clarity of what really HRM is all about and its broad dimensions. Senior Prof. Henarath Opatha has fulfilled a felt void in presenting a prolific volume on “Sustainable HRM”

    Auxin-induced SCFTIR1-Aux/IAA interaction involves stable modification of the SCFTIR1 complex

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    The plant hormone auxin can regulate gene expression by destabilizing members of the Aux/IAA family of transcriptional repressors. Auxin-induced Aux/IAA degradation requires the protein-ubiquitin ligase SCFTIR1, with auxin acting to enhance the interaction between the Aux/IAAs and SCIFTIR1. SKP1, Cullin, and an F-box-containing protein (SCF)-mediated degradation is an important component of many eukaryotic signaling pathways. In all known cases to date, the interaction between the targets and their cognate SCFs is regulated by signal-induced modification of the target. The mechanism by which auxin promotes the interaction between SCFTIR1 and Aux/IAAs is not understood, but current hypotheses propose auxin-induced phosphorylation, hydroxylation, or proline isomerization of the Aux/IAAs. We found no evidence to support these hypotheses or indeed that auxin induces any stable modification of Aux/IAAs to increase their affinity for SCFTIR1. Instead, we present data suggesting that auxin promotes the SCIFTIR1-Aux/IAA interaction by affecting the SCIF component, TIR1, or proteins tightly associated with it

    Application of Remote Sensing and Geographic Information System for Assessment of Flood Risk on the Major Downstream Areas of Gombe Metropolis, Nigeria

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    The world‘s population is rapidly becoming more urbanized as the world seen a swift urban population increase. Gombe Metropolis is among the urban areas of Nigeria affected by the consequence of frequent seasonal floods leading to an unpropitious effect on the metropolitan communities. These urbanization dynamics has caused a rapid urban growth through the transformation of many different land uses into the built-up environment. As a result, flood risk in the metropolis has been rising in recent years and efforts by the people and government to mitigate the flood risk have not been fully successful. Thus, this paper attempts to examine the nature of flood risk on the major downstream areas of Gombe metropolis. Fundamentally, this study applied Geographic Information System and Remote Sensing as a tool for integration of spatiotemporal data for modeling and comparison of urban development scenarios and its consequential effect in creating flood risk on the downstream areas of Gombe Metropolis. Thus, GIS and Remote Sensing have been applied to detect land use/land cover changes, by looking at the trend in Land use/Land Cover Change from 2003 to 2014 in the Gombe Metropolis. Accordingly, the study identified Land use/Land cover types in different residential areas of the metropolis with more emphasis on the building density in each area. Finally, Gombe Metropolis Flood Risk Zones were detected and developed into Gombe Metropolis Flood Risk Map. The paper was able to reveal a significant growth of built-up environment and the occupation of floodplains in the downstream areas as the main factors for flood risk in Gombe Metropolis. However, the flood risk index established that the residential areas found on the very high to high flood risk zones include Barunde, Government Residential Areas/Gabuka, Pantami, Dawaki, and Tudun Wada. It was further revealed that the residential areas in the moderate flood risk zone are, Jankai, Jekadafari, Herwagana, Bolari/Madaki and MUAK.Keywords: Geographic Information System, Flood risk, Gombe Metropolis, Remote sensin

    A combinatorial TIR1/AFB–Aux/IAA co-receptor system for differential sensing of auxin

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    The plant hormone auxin regulates virtually every aspect of plant growth and development. Auxin acts by binding the F-box protein transport inhibitor response 1 (TIR1) and promotes the degradation of the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) transcriptional repressors. Here we show that efficient auxin binding requires assembly of an auxin co-receptor complex consisting of TIR1 and an Aux/IAA protein. Heterologous experiments in yeast and quantitative IAA binding assays using purified proteins showed that different combinations of TIR1 and Aux/IAA proteins form co-receptor complexes with a wide range of auxin-binding affinities. Auxin affinity seems to be largely determined by the Aux/IAA. As there are 6 TIR1/AUXIN SIGNALING F-BOX proteins (AFBs) and 29 Aux/IAA proteins in Arabidopsis thaliana, combinatorial interactions may result in many co-receptors with distinct auxin-sensing properties. We also demonstrate that the AFB5–Aux/IAA co-receptor selectively binds the auxinic herbicide picloram. This co-receptor system broadens the effective concentration range of the hormone and may contribute to the complexity of auxin response

    The GCR2 Gene Family Is Not Required for ABA Control of Seed Germination and Early Seedling Development in Arabidopsis

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    BACKGROUND: The plant hormone abscisic acid (ABA) regulates diverse processes of plant growth and development. It has recently been proposed that GCR2 functions as a G-protein-coupled receptor (GPCR) for ABA. However, the structural relationships and functionality of GCR2 have been challenged by several independent studies. A central question in this controversy is whether gcr2 mutants are insensitive to ABA, because gcr2 mutants were shown to display reduced sensitivity to ABA under one experimental condition (e.g. 22 degrees C, continuous white light with 150 micromol m(-2) s(-1)) but were shown to display wild-type sensitivity under another slightly different condition (e.g. 23 degrees C, 14/10 hr photoperiod with 120 micromol m(-2) s(-1)). It has been hypothesized that gcr2 appears only weakly insensitive to ABA because two other GCR2-like genes in Arabidopsis, GCL1 and GCL2, compensate for the loss of function of GCR2. PRINCIPAL FINDINGS: In order to test this hypothesis, we isolated a putative loss-of-function allele of GCL2, and then generated all possible combinations of mutations in each member of the GCR2 gene family. We found that all double mutants, including gcr2 gcl1, gcr2 gcl2, gcl1 gcl2, as well as the gcr2 gcl1 gcl2 triple mutant displayed wild-type sensitivity to ABA in seed germination and early seedling development assays, demonstrating that the GCR2 gene family is not required for ABA responses in these processes. CONCLUSION: These results provide compelling genetic evidence that GCR2 is unlikely to act as a receptor for ABA in the context of either seed germination or early seedling development

    Misregulation of the LOB domain gene DDA1 suggests possible functions in auxin signalling and photomorphogenesis

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    The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene family encodes plant-specific transcription factors. In this report, the LBD gene DOWN IN DARK AND AUXIN1 (DDA1), which is closely related to LATERAL ORGAN BOUNDARIES (LOB) and ASYMMETRIC LEAVES2 (AS2), was characterized. DDA1 is expressed primarily in vascular tissues and its transcript levels were reduced by exposure to exogenous indole-3-acetic acid (IAA or auxin) and in response to dark exposure. Analysis of a T-DNA insertion line, dda1-1, in which the insertion resulted in misregulation of DDA1 transcripts in the presence of IAA and in the dark revealed possible functions in auxin response and photomorphogenesis. dda1-1 plants exhibited reduced sensitivity to auxin, produced fewer lateral roots, and displayed aberrant hypocotyl elongation in the dark. Phenotypes resulting from fusion of a transcriptional repression domain to DDA1 suggest that DDA1 may act as both a transcriptional activator and a transcriptional repressor depending on the context. These results indicate that DDA1 may function in both the auxin signalling and photomorphogenesis pathways

    Defining binding efficiency and specificity of auxins for SCF(TIR1/AFB)-Aux/IAA co-receptor complex formation.

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    Structure-activity profiles for the phytohormone auxin have been collected for over 70 years, and a number of synthetic auxins are used in agriculture. Auxin classification schemes and binding models followed from understanding auxin structures. However, all of the data came from whole plant bioassays, meaning the output was the integral of many different processes. The discovery of Transport Inhibitor-Response 1 (TIR1) and the Auxin F-Box (AFB) proteins as sites of auxin perception and the role of auxin as molecular glue in the assembly of co-receptor complexes has allowed the development of a definitive quantitative structure-activity relationship for TIR1 and AFB5. Factorial analysis of binding activities offered two uncorrelated factors associated with binding efficiency and binding selectivity. The six maximum-likelihood estimators of Efficiency are changes in the overlap matrixes, inferring that Efficiency is related to the volume of the electronic system. Using the subset of compounds that bound strongly, chemometric analyses based on quantum chemical calculations and similarity and self-similarity indices yielded three classes of Specificity that relate to differential binding. Specificity may not be defined by any one specific atom or position and is influenced by coulomb matrixes, suggesting that it is driven by electrostatic forces. These analyses give the first receptor-specific classification of auxins and indicate that AFB5 is the preferred site for a number of auxinic herbicides by allowing interactions with analogues having van der Waals surfaces larger than that of indole-3-acetic acid. The quality factors are also examined in terms of long-standing models for the mechanism of auxin binding
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