1,720,962 research outputs found
Improving aesthetic and diversity of bermudagrass lawn in its dormancy period
No full textAmong warm season grasses, Cynodon dactylon (L.) Pers, commonly called bermudagrass, is one of the species that better tolerates drought stress and is the most widely employed for turf in Italy.When temperatures drop below 0 °C, bermudagrass plants enter dormancy and eventually leaves turn brown. In spring, exit from dormancy occurs when soil temperatures persist for several days with an average above 10 °C. The management of an ornamental turf during dormancy could include the use of other herbaceous species able to enhance aesthetic quality, although no study has so far been carried out on the potential for combined planting of warm season grasses, wildflowers and/or bulbous species. The present study was carried out to (a) evaluate the possibility of integrating into the dormant Cynodon dactylon x C. Transvaalensis cv. Tifway 419 lawn some plants able to enhance the ornamental aspect and biodiversity, (b) attempt to identify the best species, (c) observe phenomena of competition, and (d) define the protocol for cultivation of a lawn composed of hybrid bermudagrass, bulbous, annual and perennial herbaceous plant species.The experiment was carried out on a mature (over 5 years-old) sward of hybrid bermudagrass on which eight bulbous species (geophytes) were planted and eight species of native forbs (wildflowers) were sown. Forbs that could coexist after two years with bermudagrass were B. perennis and G. molle. Concerning the bulbous species C. pulchellus, M. neglectum, G. nivalis and N. minor were suitable to be planted in a Bermuda grass. The presence of these species on a dormant bermudagrass turf improved the aesthetical quality and the diversity of the vegetation; as the studied species are able to attract pollinating insects therefore, support a habitat. Further studies will be required to test the most suitable forbs as a mix in combination with bulbous species
Turfgrass spectral reflectance: simulating satellite monitoring of spectral signatures of main C3 and C4 species
No full textIn recent years, within the European Union several legislative, monitoring and
coordinating actions have been undertaken to encourage sustainable use of resources,
reduction in the use of chemicals and improvement of the urban environment. In this
respect, two concepts that are strictly related to most of the aspects above are: ‘‘precision
agriculture’’ and ‘‘precision conservation’’ and more specifically ‘‘precision turfgrass
management.’’ Optical sensing has become a crucial part of precision turfgrass management
and spectral reflectance in particular has been an active area of research for many
years. However, while turfgrass status evaluation by proximity-sensed spectral reflectance
appears to be an established and reliable practice, much more could be achieved in terms of
monitoring of large turfgrass areas through remote sensing, and in particular through
satellite imagery. This paper reports the results of a trial attempting to evaluate the spectral
signatures of several turfgrass species and cultivars, for future use in turfgrass satellite
monitoring. Our experimental study focused on 20 turfgrass species/varieties including
perennial ryegrasses, tall fescues, kentucky bluegrasses, bermudagrass ecotypes, seeded
commercial bermudagrasses, vegetatively propagated bermudagrasses, Zoysia japonica
and non-japonica zoysiagrasses. Various biological and agronomical parameters were
studied and turfgrass spectral reflectance for all entries was gathered. Vegetation indices
were calculated by simulating the available wavelengths deriving from World View 2
satellite imagery. Results showed that within the same species selected vegetation indices
are often able to discriminate between different varieties that have been established and
maintained with identical agronomical practice
Monitoring turfgrass species and cultivars by spectral reflectance
Full text linkLike all modern agriculture sectors, turfgrass productionand management is headed towards cost reduction, resourceoptimization and reduction of the environmentalimpact. In recent years the development of newtechnologies has provided new tools for monitoringagricultural crops. In particular, the combined adoptionof geographic information systems, global positioningsystems, multispectral lenses on board satellitesand cartographic techniques allow a large scalemanagement of agricultural resources. This paper reportsthe results of a trial attempting to evaluate thespectral signatures of several turfgrass species\cultivars,for future use in satellite monitoring. This experimentalstudy focused on 20 turfgrass species\cultivars,including perennial ryegrasses, tall fescues, kentuckybluegrasses, bermudagrasses (ecotypes, seededand vegetatively propagated cultivars) and zoysiagrasses.Various agronomical and biological parameterswere studied (quality, colour, dry matter, chlorophyll,carotenoids, nitrogen content) and turfgrass spectralreflectance for all entries was gathered. Results showedthat, within the same species, selected vegetation indicesare often able to discriminate between differentcultivars that have been established and maintainedwith identical agronomical practices. Evaluation ofthe spectral reflectance of plants using field spectroradiometryprovides the possibility to identify differentspecies\ cultivars, especially through the use of hyperspectralproximity and remote sensing
SPROUTING AND PLANT REGENERATION CAPABILITY IN SALINE CONDITIONS OF SEASHORE PASPALUM, MANILAGRASS, AND HYBRID BERMUDAGRASS STOLONS
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Warm-season turfgrass species generate sports surfaces with different playability
Full text linkSynthetic sports surfaces are increasingly subject to standardization of athlete-surface and ball-surface interactions (playability parameters). Such standardizations have led to an increase in the level of the engineering and predictability of these surfaces, and as such may be beneficial also for natural turf. In warm and temperate climates, many natural turf sports surfaces are established with warm-season (C4) turfgrass species due to their suitability to the environment in such areas. This study was aimed at evaluating the Féderation Internationale de Football Association (FIFA)-standard playing characteristics of different sports turf surfaces obtained from three commonly used C4 turfgrass species: 1) ‘Tifway 419’ hybrid bermudagrass (Cynodon dactylon var. dactylon × C. transvaalensis), 2) ‘Zeon’ manilagrass (Zoysia matrella), and 3) ‘Salam’ seashore paspalum (Paspalum vaginatum) for factors concerning leaf tissue (silica, lignin, water content) and canopy structure (shoot density, leaf architecture, stolon density, etc.). Results showed that surfaces of different C4 turfgrass species generate different playability parameters, with seashore paspalum being a harder faster surface, manilagrass being a softer slower surface, and hybrid bermudagrass showing intermediate characteristics. These playing quality results were associated with certain specific canopy biometrical/morphological parameters such as shoot density, horizontal stem density (HSD), leaf section, and, to a lesser extent, to certain plant tissue compounds (lignin, silica)
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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