122,525 research outputs found
The Stanley-Reisner ideals of polygons as set-theoretic complete intersections
No full textWe show that the Stanley–Reisner ideal of the one-dimensional simplicial complex whose diagram is an n-gon is always a set-theoretic complete intersection in any positive characteristic
Arithmetical ranks of Stanley-Reisner ideals of simplicial complexes with a cone
No full textWhen a cone is added to a simplicial complex Δ over one of its faces, we investigate the relation between the arithmetical ranks of the Stanley–Reisner ideals of the original simplicial complex and the new simplicial complex Δ′. In particular, we show that the arithmetical rank of the Stanley–Reisner ideal of Δ′ equals the projective dimension of the Stanley–Reisner ring of Δ′ if the corresponding equality holds for Δ
Electron transfer characteristics of 2′-deoxy-2′-fluoro-arabinonucleic acid, a nucleic acid with enhanced chemical stability
No full textThe non-biological nucleic acid 2′-deoxy-2′-fluoro-arabinonucleic acid (2′F-ANA) may be of use because of its higher chemical stability than DNA in terms of resistance to hydrolysis and nuclease degradation. In order to investigate the charge transfer characteristics of 2′F-ANA, of relevance to applications in nucleic acid-based biosensors and chip technologies, we compare the electronic couplings for hole transfer between stacked nucleobase pairs in DNA and 2′F-ANA by carrying out density functional theory (DFT) calculations on geometries taken from molecular dynamics simulations. We find similar averages and distribution widths of the base-pair couplings in the two systems. On the basis of this result, 2′F-ANA is expected to have charge transfer properties similar to those of DNA, while offering the advantage of enhanced chemical stability. As such, 2′F-ANA may serve as a possible alternative to DNA for use in a broad range of nanobiotechnological applications. Furthermore, we show that the (experimentally observed) enhanced chemical stability resulting from the backbone modifications does not cause reduced fluctuations of the base-pair electronic couplings around the values found for "ideal" B-DNA (with standard step parameter values). Our study also supports the use of a DFT implementation, with the M11 functional, of the wave function overlap method to compute effective electronic couplings in nucleic acid systems
Identifying realistic recovery targets and conservation actions for tigers in a human dominated landscape using spatially-explicit densities of wild prey and their determinants
No full textAim
Setting realistic population targets and identifying actions for site and landscape-level recovery plans are critical for achieving the global target of doubling wild tiger numbers by 2022. Here, we estimate the spatially explicit densities of wild ungulate prey across a gradient of disturbances in two disjunct tiger habitat blocks (THBs) covering 5212 km2, to evaluate landscape-wide conditions for tigers and identify opportunities and specific actions for recovery.
Location
Western Terai Arc Landscape, India.
Methods
Data generated from 96 line transects in 15 systematically selected geographical cells (166.5 km2) were used to estimate spatially explicit densities of six wild ungulate prey species at a fine scale (1 km2). Employing distance-based density surface models, we derived species-specific estimates within three major forest land management categories (inviolate protected areas (PA), PAs with settlements and multiple-use forests). By scaling estimated prey densities using an established relationship, we predicted the carrying capacity for tigers within each THB.
Results
Species-specific responses of the six wild ungulates to natural-habitat and anthropogenic covariates indicated the need for targeted prey recovery strategies. Inviolate PAs supported the highest prey densities compared with PAs with settlements and multiple-use forests, and specifically benefited the principal tiger prey species (chital Axis axis and sambar Rusa unicolor). The estimated mean prey density of 35.16 (±5.67) individuals per km2 can potentially support 82 (62–106) and 299 (225–377) tigers across THB I and THB II, which currently support 2 (2–7) and 225 (199–256) tigers, respectively. This suggests a potential c. 68% increase in population size given existing prey abundances. Finally, while THB I represents a potential tiger recovery site given adequate prey, PAs where resettlement of pastoralists is underway represent potential prey recovery sites in THB II.
Main conclusions
This systematic approach of setting realistic population targets and prioritizing spatially explicit recovery strategies should aid in developing effective landscape conservation plans towards achieving global tiger conservation targets
Small forests, big ambitions and a hard reality - Community Forestry in Nepal
No full textCommunity forestry in Nepal is intended to reduce poverty by sustainable management of forests. Timber is one of the most high-value forest products, especially in the case of Sal (Shorea robusta) forests in the Terai region of Nepal. Despite having several advantages, including high value forests on fertile land, connection with transportation networks, and being close to regional markets, community forests in the Terai region produce little or no timber from their Sal forests. This research looks at what is affecting the production of Sal timber from community forests. Three aspects of community forest user groups (CFUG) are examined using institutional economics, transaction cost economics and micro-economics. First, the scale of CFUG operations is examined in terms of their ability to profitably carry out logging and organise market sales. Second, the capacity of CFUGs to carry out logging in terms of internal physical and human resources, and property rights is examined. Finally, barriers to vertical integration with the market in terms of contracting and cooperation with other CFUGs are investigated. To answer these questions, data was collected from 85 CFUGs and interviews were carried out with 39 key respondents from CFUGs, government agencies, and private firms. The results show that the size of the forest was not an issue for harvesting and marketing logs. However, the organisational capacity of CFUGs was found to be weak because of a lack of financial resources, limited property rights over timber, control over decisions by the District Forest Office, policy constraints, and corruption. In terms of vertical integration, a lack of legal rights to enter into contracts, a high degree of uncertainty about policy and property rights, small and irregular amounts timber harvest, and the interpretation of CFUG rules by the District Forest Office were found to be barriers for the formation of long-term contracts between CFUGs and private firms, and of cooperative developments between CFUGs.Community forest user group, institutional economics, transaction cost economics, cooperatives, contractual arrangement, Nepal, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Land Economics/Use,
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A note on the Diophantine equation
No full textLet be an odd prime such that , where are positive integers and . We show that the Diophantine equation has only the positive integer solution under some conditions. The proof is based on elementary methods and a result concerning the Diophantine equation due to Ljunggren. We also verify that when with , the Diophantine equation has only the positive integer solution .
DOI:
10.1017/S000497271300098
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
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