12,909 research outputs found

    A new indicator mineral methodology based on a generic Bi-Pb-Te-S mineral inclusion signature in detrital gold from porphyry and low/intermediate sulfidation epithermal environments in Yukon Territory, Canada

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    Porphyry-epithermal and orogenic gold are two of the most important styles of gold-bearing mineralization within orogenic belts. Populations of detrital gold resulting from bulk erosion of such regions may exhibit a compositional continuum wherein Ag, Cu, and Hg in the gold alloy may vary across the full range exhibited by natural gold. This paper describes a new methodology whereby orogenic and porphyry-epithermal gold may be distinguished according to the mineralogy of microscopic inclusions observed within detrital gold particles. A total of 1459 gold grains from hypogene, eluvial, and placer environments around calc-alkaline porphyry deposits in Yukon (Nucleus-Revenue, Casino, Sonora Gulch, and Cyprus-Klaza) have been characterized in terms of their alloy compositions (Au, Ag, Cu, and Hg) and their inclusion mineralogy. Despite differences in the evolution of the different magmatic hydrothermal systems, the gold exhibits a clear Bi-Pb-Te-S mineralogy in the inclusion suite, a signature which is either extremely weak or (most commonly) absent in both Yukon orogenic gold and gold from orogenic settings worldwide. Generic systematic compositional changes in ore mineralogy previously identified across the porphyry-epithermal transition have been identified in the corresponding inclusion suites observed in samples from Yukon. However, the Bi-Te association repeatedly observed in gold from the porphyry mineralization persists into the epithermal environment. Ranges of P-T-X conditions are replicated in the geological environments which define generic styles of mineralization. These parameters influence both gold alloy composition and ore mineralogy, of which inclusion suites are a manifestation. Consequently, we propose that this methodology approach can underpin a widely applicable indicator methodology based on detrital gold

    The International Mass Loading Service

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    The International Mass Loading Service computes four loadings: a) atmospheric pressure loading; b) land water storage loading; c) oceanic tidal loading; and d) non-tidal oceanic loading. The service provides to users the mass loading time series in three forms: 1) pre-computed time series for a list of 849 space geodesy stations; 2) pre-computed time series on the global 1deg x 1deg grid; and 3) on-demand Internet service for a list of stations and a time range specified by the user. The loading displacements are provided for the time period from 1979.01.01 through present, updated on an hourly basis, and have latencies 8-20 hours.Comment: 8 pages, 3 figures, to appear in the Proceedings of the Reference Frames for Applications in Geosciences Simposium, held in Luxemboug in October 201

    Analysis of the CRISPR-Cas system in bacteriophages active on epidemic strains of Vibrio cholerae in Bangladesh.

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    CRISPR-Cas (clustered regularly interspersed short palindromic repeats-CRISPR-associated proteins) are microbial nuclease systems involved in defense against phages. Bacteria also resist phages by hosting phage-inducible chromosomal islands (PICI) which prevent phage reproduction. Vibrio cholerae which causes cholera epidemics, interacts with numerous phages in the environment and in cholera patients. Although CRISPR-Cas systems are usually carried by bacteria and archea, recently V. cholerae specific ICP1 phages were found to host a CRISPR-Cas system that inactivates PICI-like elements (PLE) in V. cholerae. We analyzed a collection of phages and V. cholerae isolated during seasonal cholera epidemics in Bangladesh, to study the distribution, and recent evolution of the phage-encoded CRISPR-Cas system. Five distinct but related phages carrying the CRISPR-Cas system, and possible CRISPR-Cas negative progenitor phages were identified. Furthermore, CRISPR arrays in the phages were found to have evolved by acquisition of new spacers targeting diverse regions of PLEs carried by the V. cholerae strains, enabling the phages to efficiently grow on PLE positive strains. Our results demonstrate a continuing arms-race involving genetic determinants of phage-resistance in V. cholerae, and the phage-encoded CRISPR-Cas system in the co-evolution of V. cholerae and its phages, presumably fostered by their enhanced interactions during seasonal epidemics of cholera

    EVALUASI STRATEGI BERSAING HOTEL X BERDASARKAN ANALISIS THE FIVE MAJOR ELEMENTS OF STRATEGY STUDI KASUS

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    Dalam usahanya untuk bertahan dalam berbagai kondisi pasar, setiap perusahaan atau organisasi seharusnya berusaha proaktif dan melakukan pembenahan serta memformulasi strategi yang diharapkan dapat berfungsi secara optimal mencapai tujuan organisasi. Setiap organisasi akan mengidentifikasi dan mengeksploitasi sumber daya yang dimiliki serta kesempatan yang ada di pasar, disesuaikan dengan kebutuhan dan tujuan masing-masing organisasi. Hal tersebut berarti strategi yang berbeda akan dipilih oleh setiap organisasi yang berbeda pula. Setiap organisasi, dalam memilih strategi, akan menyesuaikan langkahlangkah yang diambil untuk mencapai tujuan dengan sumber daya yang dimiliki. Hotel X merupakan salah satu pemain dalam sektor perdagangan hotel dan restoran di daerah Juanda, Sidoarjo. Hotel X merupakan hotel yang berdiri sejak 1993, hingga saat ini sudah menjadi hotel bintang tiga. Dengan usia hotel yang sudah sekitar dua puluh tahun, Hotel X selama ini sudah berhasil menjaga eksistensinya bahkan mampu berkembang cukup pesat dengan menambahkan unit kamar dan investasi bangunan baru. Dengan kondisi saat ini berlebihnya jumlah kamar hotel yang ditawarkan oleh hotel-hotel pesaing merupakan tantangan tersendiri bagi Hotel X untuk mempertahankan eksistensi yang sudah cukup lama terjaga. Dewasa ini dampak dari perubahan kondisi lingkungan pasar mulai terasa oleh Hotel X, diantaranya pendapatan usaha yang diperoleh mulai menurun, meningkatnya biaya pemasaran, turnover karyawan yang meningkat, dan perubahan lainnya yang menuntut Hotel X untuk segera menyesuaikan diri. Pertumbuhan usaha hotel terlalu tinggi yang tidak sebanding dengan jumlah pertumbuhan wisatawan asing maupun lokal, merupakan tantangan tersendiri bagi para pengusaha hotel dalam berkompetisi mendapatkan pelanggan, begitu juga dengan Hotel X. Untuk dapat mencapai tujuannya Hotel X telah memiliki strategi perusahaan, namun yang menjadi pertanyaan adalah, apakah strategi yang dimiliki oleh Hotel X sudah dijalankan dengan baik dan sesuai untuk memenangkan persaiangan. Peneliti berinisiatif untuk melakukan penelitian melalui evaluasi strategi yang disesuaikan dengan kondisi internal dan eksternal Hotel X dengan menggunakan The Five Major Elements of Strategy. Sesuai dengan pendapat Hambrick dan Frederickson (2001), The Five Major Elements of Strategy, strategi yang dimiliki sebuah perusahaan sangat penting untuk memiliki elemen-elemen turunan yang terpadu atau saling berkaitan sehingga dalam menjalankan strategi tersebut, perusahaan dalam mewujudkan strategi yang telah dimiliki untuk mencapai tujuannya

    Evaluation of stem borer resistance management strategies for Bt maize in Kenya based on alternative host refugia

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    Stem borers are the major insect pests of maize in Kenya. The use of Bacillus thuringiensis (Bt) technology is an effective way of controlling lepidopteran pests. However, the likelihood of development of resistance to the Bt toxins by the target stem borer species is a concern. Forages, sorghum and maize varieties were evaluated for stem borer preference and survivorship in the laboratory and field in four locations in Kenya to identify suitable species and varieties for refugia. The economics of using the different kinds of refugia was also investigated. Vegetation surveys were conducted in 15 districts of Kenya to quantify the area covered by natural refugia. The field and laboratory trials indicated highest egg production, survivorship and more exit holes in all sorghum and maize varieties and some forages. Sorghum, non-Bt Maize, and improved Napier grass varieties Kakamega 1 and Kakamega 2) should be promoted as refugia species in Kenya. Some species and cultivars were identified as cost-effective, flexible, easily adoptable and compatible with farmers’ common production practices. Refugia cultivar with multiple uses is expected to give higher pay-offs than one with single use. However, for successful management of a refugia strategy, strict stewardship is required from appropriate government or community institutions.Key words: Refugia, cost-benefit analysis, Bt-maize, insect pest resistance management

    Single-molecule measurements reveal that PARP1 condenses DNA by loop stabilization

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    Poly(ADP-ribose) polymerase 1 (PARP1) is an abundant nuclear enzyme that plays important roles in DNA repair, chromatin organization and transcription regulation. Although binding and activation of PARP1 by DNA damage sites has been extensively studied, little is known about how PARP1 binds to long stretches of undamaged DNA and how it could shape chromatin architecture. Here, using single-molecule techniques, we show that PARP1 binds and condenses undamaged, kilobase-length DNA subject to sub-piconewton mechanical forces. Stepwise decondensation at high force and DNA braiding experiments show that the condensation activity is due to the stabilization of DNA loops by PARP1. PARP inhibitors do not affect the level of condensation of undamaged DNA but act to block condensation reversal for damaged DNA in the presence of NAD+. Our findings suggest a mechanism for PARP1 in the organization of chromatin structure

    Innovator resilience potential: A process perspective of individual resilience as influenced by innovation project termination

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    Innovation projects fail at an astonishing rate. Yet, the negative effects of innovation project failures on the team members of these projects have been largely neglected in research streams that deal with innovation project failures. After such setbacks, it is vital to maintain or even strengthen project members’ innovative capabilities for subsequent innovation projects. For this, the concept of resilience, i.e. project members’ potential to positively adjust (or even grow) after a setback such as an innovation project failure, is fundamental. We develop the second-order construct of innovator resilience potential, which consists of six components – self-efficacy, outcome expectancy, optimism, hope, self-esteem, and risk propensity – that are important for project members’ potential of innovative functioning in innovation projects subsequent to a failure. We illustrate our theoretical findings by means of a qualitative study of a terminated large-scale innovation project, and derive implications for research and management

    Biologic Agents to Promote Periodontal Regeneration and Bone Augmentation

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142088/1/cap0080.pd
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