48,956 research outputs found

    Curved Track Analysis of FSO Link for Ground-to-Train Communications

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    In this work, a free space optical (FSO) link for the ground-to-train (G2T-FSO) communications is proposed. Analytical analysis is carried out for the curved rail tracks. We show that the transmitter divergence angle, the transmit power and the size of the concentration lens need to increase for the curved section of the rail track compared to the straight track. We derive the analytical expression for the received power level based on the link geometry for the case of the curved track In the worst case scenario when the curvature radius is 120 m, the transmit power at the optical base station (BS) needs to increase by over 2 dB when the concentration lens radius is increased by 5 times. Analyses also show that the received power along the track increases with the curvature radius for the same transmit power and receiver optics illustrating the effect due to link geometry. Additionally, the signal-to-noise ratio (SNR) and the bit error rate (BER) performance of the system for the curved track with different curvature radii is analysed at data rates of 10 Mbps and 100 Mbps for an additive white Gaussian noise (AWGN) channel showing a good agreement between the theoretical and the simulated BER. Finally, effect of scintillations on the G2T-FSO link performance is discussed

    Crown and regeneration responses to silviculture systems in Pine and Sal forests: preliminary results from silviculture trials in Mid-hills Nepal

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    Silviculture trial plots were established in Kavre and Lamjung districts by the EnLiFT Project (Enhancing livelihoods and food security through improved agroforestry and community forestry in Nepal) to examine stand response to selected silviculture systems – uniform shelterwood, selection system, and negative thinning and as a showcase to forest users for these silviculture systems. This paper analyses the extent of canopy gaps on these trial plots after one-year of application of silviculture treatments and regeneration development. Using crown photographs, crown cover was estimated and compared between silviculture systems. The analysis showed that rigid silviculture systems like shelterwood and selection systems created canopy gap larger than negative thinning in Pine plantations and the rate of natural regeneration was directly related with the canopy gap. However, in Shorea robusta-Castanopsis- Schima (Sal-Katus-Chilaune) forest, negative thinning created canopy gap larger than selection system due to removal of 4-D trees, majority of trees were Schima wallichii (Chilaune),which typically have large spreading crown. Although, it may be too early to conclude the relationship between regeneration development and canopy gap from the trial plots, it became clear that silviculture operations have significant role in promoting higher regeneration. Selection and shelterwood systems are better than current silviculture regime represented by negative thinning in this study.E. Cedamon, G. Paudel, M. Basyal, I. Nuberg and N. Paude

    Implementation of Anaerobic Soil Disinfestation in Florida Tomato Production

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    Anaerobic soil disinfestation (ASD) is a relatively new technique that appears to be a promising tool for soilborne pest management and crop production improvement. This new 5-page publication of the UF/IFAS Horticultural Sciences Department is intended to introduce ASD for Florida vegetable growers. Written by Bodh R. Paudel, Francesco Di Gioia, Qiang Zhu, Xin Zhao, Monica Ozores-Hampton, Marilyn E. Swisher, Kaylene Sattanno, Jason C. Hong, and Erin N. Rosskopf. https://edis.ifas.ufl.edu/hs134

    Self-archiving practice and the influence of publisher policies in the social sciences

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    Authors in different disciplines exhibit very different behaviours on the so-called ‘green’ road to open access, i.e. self-archiving. This study looks at the self-archiving behaviour of authors publishing in leading journals in six social science disciplines. It tests the hypothesis that authors are self-archiving according to the norms of their respective disciplines rather than following self-archiving policies of publishers, and that, as a result, they are self-archiving significant numbers of publisher PDF versions. It finds significant levels of self-archiving, as well as significant self-archiving of the publisher PDF version, in all the disciplines investigated. Publishers’ self-archiving policies have no influence on author self-archiving practice

    Author Co-Citation Analysis (ACA): a powerful tool for representing implicit knowledge of scholar knowledge workers

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    In the last decade, knowledge has emerged as one of the most important and valuable organizational assets. Gradually this importance caused to emergence of new discipline entitled ―knowledge management‖. However one of the major challenges of knowledge management is conversion implicit or tacit knowledge to explicit knowledge. Thus Making knowledge visible so that it can be better accessed, discussed, valued or generally managed is a long-standing objective in knowledge management. Accordingly in this paper author co- citation analysis (ACA) will be proposed as an efficient technique of knowledge visualization in academia (Scholar knowledge workers)

    Analytical study of contents of LANL physics and cross-listed e-print archives, 1994-2002

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    The frontiers of physics and cross-listed e-print archives posted during the years 1994-2002 at http://www.arxiv.org/archives/physics web service of Los Alamos National Laboratory (LANL) are explored from 7770 submissions. E-print archives posted to top most six physics-cross-listed research categories besides physics (5390) are: Condensed matter (754), Quantum physics (279), Astrophysics (222), Chemical physics (129), High energy physics - Phenomenology (118), and High energy physics-Theory (100). Prominent contributors are B.G. Sidharth (India), V.V. Flambaum (Australia), Antonina N. Fedorova (Russia), and Michael G. Zeitlin (Russia). Most preferred journals for rechannelising e-print archives are Physical Review Letters, Physical Review A, Physical Review E, Nuclear Instruments and Methods A, and Journal of Chemical Physics

    Canopy gaps and regeneration development in Pine and Sal Forests Silviculture Demonstration Plots in Midhills Nepal

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    Silviculture demonstration plots were established in Kavre and Lamjung districts by the EnLiFT Project to examine stand response to selected silviculture system ~ uniform shelterwood, selection system, and negative thinning and as a showcase to forest users for these silviculture system. This paper analysis the extent of canopy gaps on these demo plots after silviculture treatments and regeneration development one-year after treatment. Using crown photographs, crown covers are estimated and compared between silviculture systems. The analysis have shown that rigid silviculture systems like shelterwood and selection system can create significant canopy gaps than negative thinning in pine plantations and that the rate of natural regeneration is directly related with the canopy gaps. In Sal-Katus-Chilaune forest however, negative thinning created canopy gaps larger than selection silviculture demo plots due to removal of 4-D trees, majority are Chilaune trees, which typically have large spreading crown. Although conclusion from the demo plots at this stage may be too early to make on regeneration growth and canopy gap relationship, it is clear that silviculture operations have significant role in promoting higher rate regeneration growth and that rigid silviculture operations like selection and shelterwood systems are better than current silviculture regime represented by negative thinning in this study.Edwin Cedamon, Govinda Paudel, Madan Basyal, Ian Nuberg and Naya Paude

    A systematic review and meta-analysis on the efficacy of vaccination against colibacillosis in broiler production.

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    Colibacillosis, a disease caused by Escherichia coli in broiler chickens has serious implications on food safety, security, and economic sustainability. Antibiotics are required for treating the disease, while vaccination and biosecurity are used for its prevention. This systematic review and meta-analysis, conducted under the COST Action CA18217-European Network for Optimization of Veterinary Antimicrobial Treatment (ENOVAT), aimed to assess the efficacy of E. coli vaccination in broiler production and provide evidence-based recommendations. A comprehensive search of bibliographic databases, including, PubMed, CAB Abstracts, Web of Science and Agricola, yielded 2,722 articles. Following a defined protocol, 39 studies were selected for data extraction. Most of the studies were experimental infection trials, with only three field studies identified, underscoring the need for more field-based research. The selected studies reported various types of vaccines, including killed (n = 5), subunit (n = 8), outer membrane vesicles/protein-based (n = 4), live/live-attenuated (n = 16), and CpG oligodeoxynucleotides (ODN) (n = 6) vaccines. The risk of bias assessment revealed that a significant proportion of studies reporting mortality (92.3%) or feed conversion ratio (94.8%) as outcomes, had "unclear" regarding bias. The meta-analysis, focused on live-attenuated and CpG ODN vaccines, demonstrated a significant trend favoring both vaccination types in reducing mortality. However, the review also highlighted the challenges in reproducing colibacillosis in experimental setups, due to considerable variation in challenge models involving different routes of infection, predisposing factors, and challenge doses. This highlights the need for standardizing the challenge model to facilitate comparisons between studies and ensure consistent evaluation of vaccine candidates. While progress has been made in the development of E. coli vaccines for broilers, further research is needed to address concerns such as limited heterologous protection, practicability for application, evaluation of efficacy in field conditions and adoption of novel approaches

    Dual Hierarchy for Gravitational n-body

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    The n-body problem is the simulation of pair-wise interactions between n objects. This problem appears in many forms, with the classic example being the modeling of gravitational forces between point masses, necessary for cosmological simulations. Many approximation approaches have been devised to reduce the complexity of this problem.t-SNE is a data visualization method that requires repeatedly solving a variant of the n-body problem. A recent paper (An Efficient Dual-Hierarchy t-SNE Minimization, van de Ruit et. al.) proposes a novel algorithm that outperforms other t-SNE minimization methods on medium-scale datasets. The report proves the viability of a dual-traversal method that uses an embedding tree to emit forces and an independent field tree to collect forces. Because the embedding tree is a Linear-BVH and the field tree is an orthtree built to a fixed depth, the overall algorithm has linear complexity.This thesis demonstrates how the dual-tree approach can be adapted for gravitational n-body simulations. Following this, it measures the performance against similar implementations of other algorithms and shows that while the adapted Dual Hierarchy approach is faster than Barnes-Hut, it is outperformed by the Fast Multipole Method on realistic large-scale cosmological datasets.https://github.com/JacksonCampolattaro/n-body Git repository containing an implementation of the adapted Dual Hierarchy algorithm for Gravitational n-body, as well as implementations of several other common algorithms compared against during benchmarking.Computer Engineerin

    Bibliographics for the 983 eprints in the live archives of E-LIS : trends and status report up to 7th July 2004, based on author-self-archiving metadata

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    The priority for ideas and philosophy related to "Network Theory" have been traced back and documented by Braun(2004),and credit goes to Karinthy(1929).The IT has empowered to realise it, as the most practical phenomena and it is no more a humour. The OAI (Open Archives Initiatives)and ACIS (Academic Contributor Information System)are progressive in the direction ,which may lead to realise the "Collective Genius" at global level. Focus of present study is on Author-Self-Archiving (A-S-A)Metadata of the 983 Eprints in the Live Archives of the E-LIS (EPrints of Library and Information Science),which were approved till 7th July 2004.The A-S-A Metadata was used for librametric analysis. Self-explanatory bibliographics are illustrated.The highlights include: Conference papers (34%); highest approval, June 2004 (28%); published archives (76%);not refereed (52%); not in public domain (60%); highest self-archiving-author (De Robbio, Antonella).The Nos. of EPrints having single JITA domain specifications were: Theoretical and general aspects of libraries and information(27); Information use and sociology of information(80);Users,literacy and reading(13);Libraries as physical collections(30);Publishing and legal issues(57);Management(13);Industry, profession and education(36);Information sources, supports, channels(113) ; Information treatment for information services, Information functions and techniques (101); Technical services libraries, archives and museums(25); Housing technologies(1); Information technology and library technology(92); and Inter-domainery (395) i.e. having specifications of two or more than two JITA classes
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