157 research outputs found

    Forestry on the Island of Taiwan, ROC - The State of the Art

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    The forests of Taiwan vary from lush subtropical vegetation to subalpine coniferous associations. Topography is exceedingly rugged, and stands border on the verge of silvicultural inoperability. In the 1950s and 1960s, the wood products industry in the Republic of China was of paramount importance; the production of high-quality sawtimber from old-growth cypress (Cupressaceae) stands provided the financial capital that built one of the most prosperous national economies in the modern world. In the 1980s, forestry in Taiwan is a curious blend of old methods and new technologies, as modern silvicultural practices are used to reforest cutover cypress stands, to harvest and reproduce remaining old-growth stands, and to expand the silvicultural importance of other forest types on the island. Many applied research efforts would be promising in application to the forests of Taiwan, such as long-term studies of silvicultural practices on water quality, methodology of natural regeneration applied to cypress and Taiwania cryptomerioides (Taxodiaceae), uneven-aged regulation applied to bamboo, Phyllostachys pubescens (Bambusaceae), growth and yield in coniferous plantations, effectiveness of modern herbicides in controlling competition in young plantations, and application of contemporary economic assessments in the evaluation of silvicultural alternatives

    Ammonia-methane combustion in tangential swirl burners for gas turbine power generation

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    Ammonia has been proposed as a potential energy storage medium in the transition towards a low-carbon economy. This paper details experimental results and numerical calculations obtained to progress towards optimisation of fuel injection and fluidic stabilisation in swirl burners with ammonia as the primary fuel. A generic tangential swirl burner has been employed to determine flame stability and emissions produced at different equivalence ratios using ammoniaā€“methane blends. Experiments were performed under atmospheric and medium pressurised conditions using gas analysis and chemiluminescence to quantify emission concentrations and OH production zones respectively. Numerical calculations using GASEQ and CHEMKIN-PRO were performed to complement, compare with and extend experimental findings, hence improving understanding concerning the evolution of species when fuelling on ammonia blends. It is concluded that a fully premixed injection strategy is not appropriate for optimised ammonia combustion and that high flame instabilities can be produced at medium swirl numbers, hence necessitating lower swirl and a different injection strategy for optimised power generation utilising ammonia fuel blends

    Genomic tools reveal complex social organization of an invasive large mammal (\u3ci\u3eSus scrofa\u3c/i\u3e)

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    A comprehensive understanding of sociality in wildlife is vital to optimizing conservation and management efforts. However, sociality is complicated, especially for widely distributed species that exhibit substantive behavioral plasticity. Invasive wild pigs (Sus scrofa), often representing hybrids of European wild boar and domestic pigs, are among the most adaptable and widely distributed large mammals. The social structure of wild pigs is believed to be similar to European wild boar, consisting of matriarchal groups (sounders) and solitary males. However, wild pig social structure is understudied and largely limited to visual observations. Using a hierarchical approach, we incorporated genomic tools to describe wild pig social group composition in two disparate ecoregions within their invaded range in North America. The most common social unit was sounders, which are characterized as the association of two or more breeding-aged wild pigs with or without dependent offspring. In addition to sounders, pseudo-solitary females and male-dominated bachelor groups were observed at a greater frequency than previously reported. Though primarily composed of close female kin, some sounders included unrelated females. Bachelor groups were predominantly composed of young, dispersal-aged males and almost always included only close kin. Collectively, our study suggests social organization of wild pigs in their invaded range is similar to that observed among wild boar but is complex, dynamic, and likely variable across invaded habitats

    Large Charge Moment Change Lightning in an Oklahoma Mesoscale Convective System

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    On 31 May 2013, a line of severe thunderstorms developed during the local afternoon in central Oklahoma, USA. One of the supercells produced the El Reno tornado, which caused significant damage and killed several people. During the 2300 UTC hour (during the mature supercell stage and just after the tornado began), the storm produced several positive cloud-to-ground (+CG) lightning strokes that featured large (> 100 C km) impulse charge moment changes (iCMCs; charge moment during the first 2 ms after the return stroke). These discharges occurred mainly in convection, in contrast to the typical pattern of large-CMC and sprite-parent +CGs occurring mainly in stratiform precipitation regions. After this time, the line of thunderstorms evolved over several hours into a large mesoscale convective system (MCS). By the 0700 UTC hour on 1 June 2013, the large-CMC pattern had changed markedly. Large-CMC negative CGs, which were absent early in the storm's lifetime, occurred frequently within convection. Meanwhile, large-CMC +CGs had switched to occurring mainly within the broad stratiform region that had developed during the intervening period. The evolution of the large-CMC lightning in this case will be examined using a mix of national mosaics of radar reflectivity, the Oklahoma Lightning Mapping Array (OKLMA), the Charge Moment Change Network (CMCN), and the National Lightning Detection Network (NLDN). A major goal of this study is understanding how storm structure and evolution affected the production of large-CMC lightning. It is anticipated that this will lead to further insight into how and why storms produce the powerful lightning that commonly causes sprites in the upper atmosphere

    Reducing Baylisascaris procyonis Roundworm Larvae in Raccoon Latrines

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    Baylisascaris procyonis roundworms, a parasite of raccoons, can infect humans, sometimes fatally. Parasite eggs can remain viable in raccoon latrines for years. To develop a management technique for parasite eggs, we tested anthelmintic baiting. The prevalence of eggs decreased at latrines, and larval infections decreased among intermediate hosts, indicating that baiting is effective

    Probing the Intermediate-Age Globular Clusters in NGC 5128 from Ultraviolet Observations

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    We explore the age distribution of the globular cluster (GC) system of the nearby elliptical galaxy NGC 5128 using ultraviolet (UV) photometry from Galaxy Evolution Explorer (GALEX) observations, with UV - optical colors used as the age indicator. Most GCs in NGC 5128 follow the general trends of GCs in M31 and Milky Way in UV - optical color-color diagram, which indicates that the majority of GCs in NGC 5128 are old similar to the age range of old GCs in M31 and Milky Way. A large fraction of spectroscopically identified intermediate-age GC (IAGC) candidates with ~ 3-8 Gyr are not detected in the FUV passband. Considering the nature of intermediate-age populations being faint in the far-UV (FUV) passband, we suggest that many of the spectroscopically identified IAGCs may be truly intermediate in age. This is in contrast to the case of M31 where a large fraction of spectroscopically suggested IAGCs are detected in FUV and therefore may not be genuine IAGCs but rather older GCs with developed blue horizontal branch stars. Our UV photometry strengthens the results previously suggesting the presence of GC and stellar subpopulation with intermediate age in NGC 5128. The existence of IAGCs strongly indicates the occurrence of at least one more major star formation episode after a starburst at high redshift.Comment: 8 pages, 3 figures, accepted for ApJ Lette

    Clinical application of circulating tumor cells and circulating tumor DNA in uveal melanoma

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    Purpose To evaluate the feasibility of using circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) for the management of uveal melanoma (UM). Patients and Methods Low-coverage whole-genome sequencing was used to determine somatic chromosomal copy number alterations (SCNAs) in primary UM tumors, ctDNA, and whole-genome amplified CTCs. CTCs were immunocaptured using an antimelanoma-associated chondroitin sulfate antibody conjugated to magnetic beads and immunostained for melanoma antigen recognised by T cells 1 (MART1)/glycoprotein 100 (gp100)/S100 calcium-binding protein Ī² (S100Ī²). ctDNA was quantified using droplet digital polymerase chain reaction assay for mutations in the GNAQ, GNA11, PLCĪ²4, and CYSLTR2 genes. Results SCNA analysis of CTCs and ctDNA isolated from a patient with metastatic UM showed good concordance with the enucleated primary tumor. In a cohort of 30 patients with primary UM, CTCs were detected in 58% of patients (one to 37 CTCs per 8 mL of blood), whereas only 26% of patients had detectable ctDNA (1.6 to 29 copies/mL). The presence of CTCs or ctDNA was not associated with tumor size or other prognostic markers. However, the frequent detection of CTCs in patients with early-stage UM supports a model in which CTCs can be used to derive tumor-specific SCNA relevant for prognosis. Monitoring of ctDNA after treatment of the primary tumor allowed detection of metastatic disease earlier than 18F-labeled fluorodeoxyglucose positron emission tomography in two patients. Conclusion The presence of CTCs in localized UM can be used to ascertain prognostic SCNA, whereas ctDNA can be used to monitor patients for early signs of metastatic disease. This study paves the way for the analysis of CTCs and ctDNA as a liquid biopsy that will assist with treatment decisions in patients with UM

    Clinical application of circulating tumor cells and circulating tumor DNA in uveal melanoma

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    Purpose To evaluate the feasibility of using circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) for the management of uveal melanoma (UM). Patients and Methods Low-coverage whole-genome sequencing was used to determine somatic chromosomal copy number alterations (SCNAs) in primary UM tumors, ctDNA, and whole-genome amplified CTCs. CTCs were immunocaptured using an antimelanoma-associated chondroitin sulfate antibody conjugated to magnetic beads and immunostained for melanoma antigen recognised by T cells 1 (MART1)/glycoprotein 100 (gp100)/S100 calcium-binding protein Ī² (S100Ī²). ctDNA was quantified using droplet digital polymerase chain reaction assay for mutations in the GNAQ, GNA11, PLCĪ²4, and CYSLTR2 genes. Results SCNA analysis of CTCs and ctDNA isolated from a patient with metastatic UM showed good concordance with the enucleated primary tumor. In a cohort of 30 patients with primary UM, CTCs were detected in 58% of patients (one to 37 CTCs per 8 mL of blood), whereas only 26% of patients had detectable ctDNA (1.6 to 29 copies/mL). The presence of CTCs or ctDNA was not associated with tumor size or other prognostic markers. However, the frequent detection of CTCs in patients with early-stage UM supports a model in which CTCs can be used to derive tumor-specific SCNA relevant for prognosis. Monitoring of ctDNA after treatment of the primary tumor allowed detection of metastatic disease earlier than 18F-labeled fluorodeoxyglucose positron emission tomography in two patients. Conclusion The presence of CTCs in localized UM can be used to ascertain prognostic SCNA, whereas ctDNA can be used to monitor patients for early signs of metastatic disease. This study paves the way for the analysis of CTCs and ctDNA as a liquid biopsy that will assist with treatment decisions in patients with UM
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