Morphological aspects and its influence in the ecological role of two simpatric species (Lagodon rhomboides and Archosargus rhomboidalis) in Terminos lagoon, Mexico

2021 ◽  
Vol 3 (1) ◽  
pp. 41-54
Author(s):  
Karla Gabriela Feria Alvarado ◽  
Reyna Francisca Reyna Francisca ◽  
Yassir Eden Torres Rojas ◽  
Rodolfo del Río Rodríguez

In Terminos Lagoon the Sparidae family is represented mainly by Lagodon rhomboides (Lr) and Archosargus rhomboidalis (Ar), both reported with herbivorous habits, however, the record of carnivorous or omnivorous habits in other regions raises questions about the correct classification of the ecological role they play and the influences that morphological aspects may have (e.g. oral difference and intestine length). The objective was to analyze the trophic role (amplitude, overlap and trophic level) through the stomach content and its possible relationship with the morphological aspects of L. rhomboides. and A. rhomboidalis during three climatic seasons (30 individuals per species per season). As results, 180 individuals were analyzed with an average total length of 14.0 ± 2.5 (cm) for both species. According to the Index Importance Geometric (IGI), Thalassia testudinum was the main item of L. rhomboides (IGI= 86.3) and A. rhomboidalis (IGI= 63.3), however, the secondary items for A. rhombiodalis (Brachidontes (Hormomya) exustus= 5.70) and L. rhomboides (Parvilucina (Parvilucina) multilineata= 16.80) were different. The trophic breadth (“Bi”) indicated that L. rhomboides. and A. rhomboidalis are specialists (BiLr= 0.02 and BiAr= 0.01). At the intraspecific level, there is high similarity (ANOSIM) in the diet of both Sparids between seasons (RLr= 0.03 and RAr= 0.05), however, at the interspecific level, low similarity was observed (Rg= 0.15), which was reflected in the NT of both Sparids (NTLr= 2.22 and NTAr= 3.71). The average buccal area was smaller in L. rhomboides (12.90 mm) compared to A. rhomboidalis (13.07 mm). Based on the intestinal index, L. rhomboides is classified. (Ii= 2.20) as herbivore, and A. rhomboidalis (Ii= 0.71) as carnivore. In conclusion, both species presented differences in trophic roles, probably related to specific morphological aspects. This information is relevant to know the vulnerability of a species from simulation studies to different phenomena such as climate change. Keywords: Herbivore, Gulf of Mexico. Protected Natural Area, ANOSIM and Coastal Lagoons.

2021 ◽  
Vol 3 (1) ◽  
pp. 55-76
Author(s):  
Bertha Nayeli Irola Sansores ◽  
Yassir Edén Torres Rojas ◽  
Alfonso Cuevas Jiménez

Terminos Lagoon is classified as a Flora and Fauna Protection Area due to the high biodiversity it registers, however, given its size, it makes total protection difficult. The objective of this study was to detect possible specific areas of conservation within the lagoon, for which an analysis of the spatiotemporal behavior of biodiversity was carried out (based on geostatistics) and thereby establish key regions of laguna de Terminos for their protection and recovery. Monthly samplings (2016-2017) were carried out by trawling with a shrimp net in 17 stations classified in 4 regions during dry (February-May), rain (June-September) and wind/winter (October-January). The organisms were identified up to the species level and the indices of abundance, richness and diversity were applied to carry out the interpolation and generation of maps. 17,950 organisms (382.9 kg) were collected and 103 species were identified. According to the interpolation of minimum curvature, at the temporal level, the rainy season was the one that presented the highest values in terms of diversity and richness, while at the spatial level, region 1 (adjacent area of Boca Atasta and Palizada river) it was the most representative during the three climatic seasons for both indices. In terms of abundance, region 2 was the one characterized by presenting the highest values. In conclusion, regions 1 and 2 represent areas of great ecological importance for the balance of biodiversity, which is why they are key areas that should be protected in Terminos Lagoon. This information would contribute significantly to knowing the state of the habitat, since it provides us with knowledge of the biological conditions of the ecosystem. Keywords: Coastal lagoons, onterpolation, Protected Natural Area, Gulf of Mexico, diversity, richness.


2007 ◽  
pp. 80-92
Author(s):  
A. Kireev

The paper studies the problem of raiders activity on the market for corporate control. This activity is considered as a product of coercive entrepreneurship evolution. Their similarities and sharp distinctions are shown. The article presents the classification of raiders activity, discribes its basic characteristics and tendencies, defines the role of government in the process of its transformation.


Author(s):  
Petar Halachev ◽  
Victoria Radeva ◽  
Albena Nikiforova ◽  
Miglena Veneva

This report is dedicated to the role of the web site as an important tool for presenting business on the Internet. Classification of site types has been made in terms of their application in the business and the types of structures in their construction. The Models of the Life Cycle for designing business websites are analyzed and are outlined their strengths and weaknesses. The stages in the design, construction, commissioning, and maintenance of a business website are distinguished and the activities and requirements of each stage are specified.


2017 ◽  
Vol 19 (1) ◽  
pp. 5-24 ◽  
Author(s):  
E. I. Shnyukova ◽  
E. K. Zolotareva
Keyword(s):  

Author(s):  
Robert Hasegawa

Musicians have long framed their creative activity within constraints, whether imposed externally or consciously chosen. As noted by Leonard Meyer, any style can be viewed as an ensemble of constraints, requiring the features of the artwork to conform with accepted norms. Such received stylistic constraints may be complemented by additional, voluntary limitations: for example, using only a limited palette of pitches or sounds, setting rules to govern repetition or transformation, controlling the formal layout and proportions of the work, or limiting the variety of operations involved in its creation. This chapter proposes a fourfold classification of the limits most often encountered in music creation into material (absolute and relative), formal, style/genre, and process constraints. The role of constraints as a spur and guide to musical creativity is explored in the domains of composition, improvisation, performance, and even listening, with examples drawn from contemporary composers including György Ligeti, George Aperghis, and James Tenney. Such musical constraints are comparable to self-imposed limitations in other art forms, from film (the Dogme 95 Manifesto) and visual art (Robert Morris’s Blind Time Drawings) to the writings of authors associated with the Oulipo (Ouvroir de littérature potentielle) such as Georges Perec and Raymond Queneau.


Author(s):  
Victor L. Shabanov ◽  
Marianna Ya Vasilchenko ◽  
Elena A. Derunova ◽  
Andrey P. Potapov

The aim of the work is to find relevant indicators for assessing the relationship between investments in fixed assets in agriculture, gross output of the industry, and agricultural exports using tools for modeling the impact of innovation and investment development on increasing production and export potential in the context of the formation of an export-oriented agricultural economy. The modeling methodology and the proposed estimating and forecasting tools for diagnosing and monitoring the state of sectoral and regional innovative agricultural systems are used to analyze the relationship between investments in fixed assets in agriculture, gross output of the industry, and agricultural exports based on the construction of the classification of Russian regions by factors that aggregate these features to diagnose incongruence problems and to improve institutional management in regional innovative export-oriented agrosystems. Based on the results of the factor analysis application, an underestimated role of indicators of investment in agriculture, the intensity and efficiency of agricultural production, were established. Based on the results of the cluster analysis, the established five groups of regions were identified, with significant differences in the level of investment in agriculture, the volume of production of the main types of agricultural products, and the export and exported food. The research results are of practical value for use in improving institutional management when planning reforms and transformations of regional innovative agrosystems.


2021 ◽  
Vol 4 (2) ◽  
pp. e000196
Author(s):  
Yue Wu ◽  
Xiaosi Jin ◽  
Yuhao Zhang ◽  
Jing Zheng ◽  
Rulai Yang

Congenital heart disease (CHD) is the most common of congenital cardiovascular malformations associated with birth defects, and it results in significant morbidity and mortality worldwide. The classification of CHD is still elusive owing to the complex pathogenesis of CHD. Advances in molecular medicine have revealed the genetic basis of some heart anomalies. Genes associated with CHD might be modulated by various epigenetic factors. Thus, the genetic and epigenetic factors are gradually accepted as important triggers in the pathogenesis of CHD. However, few literatures have comprehensively elaborated the genetic and epigenetic mechanisms of CHD. This review focuses on the etiology of CHD from genetics and epigenetics to discuss the role of these factors in the development of CHD. The interactions between genetic and epigenetic in the pathogenesis of CHD are also elaborated. Chromosome abnormalities and gene mutations in genetics, and DNA methylations, histone modifications and on-coding RNAs in epigenetics are summarized in detail. We hope the summative knowledge of these etiologies may be useful for improved diagnosis and further elucidation of CHD so that morbidity and mortality of children with CHD can be reduced in the near future.


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