1,721,051 research outputs found
Sex Determination in Reptiles: A Review
No full textReptile biodiversity is rapidly declining, with over 11,733 recognized species across 1226 genera being documented, many of which are endangered. Captive breeding programs play a crucial role in conservation; however, effective management requires accurate sex determination, especially due to the fact that many reptile species exhibit minimal or no sexual dimorphism. When present, sexual dimorphism manifests as differences such as size, coloration, and morphological features influenced by evolutionary pressures and hormones. Various sex determination techniques are employed due to the lack of external sexual characteristics in many species. These methods include probing, hydrostatic eversion, popping, ultrasound, CT, radiography, contrast radiography, endoscopy, and genotypic sex determination. Accurate sex determination is crucial for the success of captive breeding programs and the conservation of reptile species. Advanced imaging and molecular methods offer promising non-invasive alternatives but may not be universally accessible or effective. An understanding of the unique reproductive anatomy and the use of appropriate sexing techniques are fundamental to establishing breeding groups, preventing aggressive behaviours among groups, and ensuring the long-term survival of endangered reptile populations
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
.: Comparative study about the use of Oxytocin chlorohydrate administered intravenous or intramuscolar for induction of eggs depositino in non obstructive eggs retention in captive breed turtles
No full textIs the household microwave recommended to obtain antioxidant-rich extracts from Lycium barbarum leaves?
No full textNowadays, much interest is devoted to the extraction of plant materials, considering also their waste and by-products, to obtain antioxidant-rich products. The effect of household microwave-assisted extraction (MAE) on the phenolic content and antioxidant activity of Lycium barbarum leaf extracts was investigated. An experimental design approach was adopted considering solid/liquid ratio (1, 3, and 5 g of leaves in 150 mL water), irradiation time (1, 3, and 5 min), and microwave power (300, 400, and 500 W) as independent variables. These three factors and their interactions were studied to evaluate the effect of MAE conditions on the responses of total phenolic content, antioxidant activity, and chlorogenic acid content. The results showed that the analytical parameters were positively influenced by the solid/liquid ratio and time. On the contrary, microwave power was inversely correlated with the investigated responses. This research revealed that microwave extraction conditions should be carefully monitored to obtain bioactive-rich aqueous extracts with high antioxidant activity. A comparison with household traditional methods showed an unexpected lower phenolic content and antioxidant activity for MAE extract in respect to the decoction and infusion. In fact, it was found that L. barbarum leaf infusion had the best functional properties, regarding the investigated characteristics. The outcome of this study has implications for raising awareness that household preparation conditions strongly affect the health properties of herbal extracts
Enantioseparations by high-performance liquid chromatography based on chiral ligand exchange
No full textAlthough the first application of chiral ligand-exchange chromatography (CLEC) in HPLC dates back to late 1960s, this enantioselective strategy still represents the elective choice for the direct analysis of compounds endowed with chelating moieties. As a specific feature of the CLEC mechanism, the interaction between the chiral selector and the enantiomer does not take place in direct contact. Indeed, it is mediated by a central metal ion that, acting as a Lewis acid, simultaneously coordinates the two species, selector and analyte, through the activation of dative bonds. As a consequence, two diastereomeric mixed ternary complexes are generated in the column, ultimately leading to the stereoisomeric discrimination. CLEC applications can be carried out both with the chiral selector included in the mobile phase (chiral mobile phase, CMP), or as a part of the stationary phase. In the latter case, the chiral selector can be either covalently immobilized onto a solid support (bonded CSP, B-CSP) or physically adsorbed onto a conventional packing material, coated chiral stationary phase (C-CSP). In this chapter, a selection of CLEC applications with CMP- and C-CSP-based chiral systems is presented
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
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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