1,721,035 research outputs found
A new coffee species from South-West Cameroon, the principal hotspot of diversity for Coffea L. (Coffeeae, Ixoroideae, Rubiaceae) in Africa
No full textStoffelen, Piet, Anthony, François, Janssens, Steven, Noirot, Michel (2021): A new coffee species from South-West Cameroon, the principal hotspot of diversity for Coffea L. (Coffeeae, Ixoroideae, Rubiaceae) in Africa. Adansonia (3) 43 (26): 277-285, DOI: 10.5252/adansonia2021v43a2
FIG. 1 in A new coffee species from South-West Cameroon, the principal hotspot of diversity for Coffea L. (Coffeeae, Ixoroideae, Rubiaceae) in Africa
No full textFIG. 1. — Phylogram based on combined trnLF, accD-psa1 and ITS data. Numbers on branches represent Bayesian Posterior Probabilities and Maximum Likelihood Bootstrap Support, respectively. An asterisk indicates a lack of support.Published as part of Stoffelen, Piet, Anthony, François, Janssens, Steven & Noirot, Michel, 2021, A new coffee species from South-West Cameroon, the principal hotspot of diversity for Coffea L. (Coffeeae, Ixoroideae, Rubiaceae) in Africa, pp. 277-285 in Adansonia (3) 43 (26) on page 280, DOI: 10.5252/adansonia2021v43a26, http://zenodo.org/record/581710
FIG. 2. — C. rizetiana Stoff. & M in A new coffee species from South-West Cameroon, the principal hotspot of diversity for Coffea L. (Coffeeae, Ixoroideae, Rubiaceae) in Africa
No full textFIG. 2. — C. rizetiana Stoff. & M.Noirot, sp. nov.: A, habit; B, node with flowers and petioles; C, detail of flower; D, fruit; E, transection of the fruit with two seeds. Vouchers deposited in BR: A-C, Stoffelen 2045; C, D, Noirot EC66, 30.X.2012 (liquid preserved collection). Scale bars: A, 3 cm; B, 2 cm; C-E, 1 cm.Published as part of Stoffelen, Piet, Anthony, François, Janssens, Steven & Noirot, Michel, 2021, A new coffee species from South-West Cameroon, the principal hotspot of diversity for Coffea L. (Coffeeae, Ixoroideae, Rubiaceae) in Africa, pp. 277-285 in Adansonia (3) 43 (26) on page 282, DOI: 10.5252/adansonia2021v43a26, http://zenodo.org/record/581710
Identifying coffee: development of a low-cost and robust barcoding assay for wild African Coffea species
No full textWith an estimated consumption of more than two billion cups a day, coffee is one of the most popular beverages in the world. Nearly all coffee is produced from the seeds of two species: Coffea arabica (Arabica coffee) and Coffea canephora (Robusta coffee). Both Arabica and Robusta coffee production is threatened by climate fluctuations and disease outbreaks, reducing yields and ravaging coffee plantations. To overcome these challenges, the potential of other wild Coffea species for the improvement of existing coffee varieties or for the development of new varieties has been studied. The Coffea genus consists of circa 130 described species that are mainly found in sub-Saharan Africa and Madagascar. Coffea species on the African continent are more closely related to Arabica and Robusta coffee. Nevertheless, the identification of African Coffea species at species level based on morphological traits can be challenging as several species seem to have overlapping trait characteristics. In this study, we developed a molecular barcoding assay consisting of eight nuclear markers between ca. 200 and 800 base pairs long that can be sequenced using Sanger sequencing. Marker regions were selected based on the output of publicly available genotyping-by-sequencing data, ensuring that each Coffea species included in this dataset had a unique allele for at least two out of eight markers. The resulting barcoding assay is a cost-efficient and accessible tool for the molecular identification of wild African Coffea species, facilitating their conservation and their application for the improvement of coffee cultivation
Identifying coffee: development of a low-cost and robust barcoding assay for wild African Coffea species
No full textWith an estimated consumption of more than two billion cups a day, coffee is one of the most popular beverages in the world. Nearly all coffee is produced from the seeds of two species: Coffea arabica (Arabica coffee) and Coffea canephora (Robusta coffee). Both Arabica and Robusta coffee production is threatened by climate fluctuations and disease outbreaks, reducing yields and ravaging coffee plantations. To overcome these challenges, the potential of other wild Coffea species for the improvement of existing coffee varieties or for the development of new varieties has been studied. The Coffea genus consists of circa 130 described species that are mainly found in sub-Saharan Africa and Madagascar. Coffea species on the African continent are more closely related to Arabica and Robusta coffee. Nevertheless, the identification of African Coffea species at species level based on morphological traits can be challenging as several species seem to have overlapping trait characteristics. In this study, we developed a molecular barcoding assay consisting of eight nuclear markers between ca. 200 and 800 base pairs long that can be sequenced using Sanger sequencing. Marker regions were selected based on the output of publicly available genotyping-by-sequencing data, ensuring that each Coffea species included in this dataset had a unique allele for at least two out of eight markers. The resulting barcoding assay is a cost-efficient and accessible tool for the molecular identification of wild African Coffea species, facilitating their conservation and their application for the improvement of coffee cultivation
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
Phylogenetic, ecological and sensory characterization of Coffea dactylifera, a wild coffee from the Democratic Republic of Congo
No full textBackground and Aims Coffee is one of the world's most valuable crops and supports the livelihoods of millions, yet it is increasingly threatened by climate change. Diversifying currently cultivated varieties is crucial for the sector's long-term sustainability. Wild coffee species may carry traits critical for climate resilience but remain largely unexplored. This study provides a first multidisciplinary assessment of Coffea dactylifera, a wild species endemic to the Democratic Republic of Congo (DRC), by comparing its phylogeny, climate niche, morphology and sensory profile with those of the wild relatives of Arabica (C. arabica) and Robusta (C. canephora) coffee.Methods We sampled wild C. dactylifera from the DRC and gathered occurrence data. A consensus phylogenetic tree was constructed using ASTRAL-III, based on DArTseq polymorphic genetic markers, and including data from 22 species. Climate niche modelling used filtered occurrence data and bioclimatic variables. Twelve morphological traits were assessed, encompassing leaf morphology, bean characteristics and plant architectural traits. The sensory quality of coffee beans was evaluated using the Fine Robusta Standards and Protocols.Key Results Coffea dactylifera was identified as a sister species to C. anthonyi, as part of the Coffea eugenioides group. It is adapted to high annual temperatures and low climate seasonality, typical of the lowland forests in Central Africa, where it grows sympatrically with C. canephora. In terms of morphology, it displays a more compact growth form and leaf characteristics that distinguish it from sympatric C. canephora individuals. Sensory evaluation revealed an average score of 78.75 points marked by the 'brown sugar' descriptor, intense sweet aftertaste and syrupy mouthfeel.Conclusions C. dactylifera may contribute to climate-resilient coffee breeding. Its genetic proximity to cultivated species, climate niche, compact growth form and promising sensory profile highlight its relevance for conservation and potential use in breeding.Research Foundation-Flanders; research mandate [FWO:1173725N]; SBBOA
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