1,720,976 research outputs found
Critical temperatures and aerobic metabolism in post-larvae of Pacific white shrimp Litopenaeus vannamei (Boone, 1931)
No full textIncreasing water temperature because of climate change decreases the oxygen concentration while increasing the oxygen requirement of species in aquatic environments. Temperature is one of the most important environmental factors affecting the physiological functions of organisms, especially poikilothermic animals, such as shrimp at all levels. In intensive shrimp culture, it is of great importance to know the tolerable temperature range of cultured species and their metabolism since this affects the physiological condition. In this study, critical temperatures (CTM: CTmin and CTmax) of Pacific white shrimp, Litopenaeus vannamei, post-larvae (PL), were determined at different acclimation temperatures of 15, 20, 25, and 30 °C. Lower and upper incipient lethal temperatures (ILT: LILT and UILT) were also calculated for the PL. The thermal windows of the PL were developed using the CTM and ILT values. The standard metabolic rate (SMR) of the PL was determined based on the oxygen consumption rate (OCR) at the different acclimation temperatures mentioned above. The acclimation temperature had a subsequent effect on the thermal tolerance and SMR of the PL (P < 0.01). The PLs of Pacific white shrimp have high thermal tolerance and can survive at extreme temperatures (CTmin and CTmax: 8.2–43.8 °C) with their large dynamic and static thermal window areas of 1128 and 931 °C2, respectively. The optimal temperature range for Pacific white shrimp PLs is the 25–30 °C range, where a decrease in SMR is determined with increasing temperature. The result of this study reveals that a range of 25–30 °C is optimal for effective PL culture of Pacific white shrim
Acute toxicity of ammonia in Meagre (Argyrosomus regius Asso, 1801) at different temperatures
No full text0000-0002-9615-5554; 0000-0003-4916-7090WOS: 000385621700021Argyrosomus regius (3.0 +/- 0.9 g) were exposed to different concentrations of ammonia in a series of acute toxicity tests by the static renewal method at three temperature levels (18, 22 and 26 degrees C) at a pH of 8.2. Low temperature clearly increased the tolerance of the fish to total ammonia nitrogen (TAN) and unionized ammonia (NH3) (P < 0.05). While the 96-h LC50 values of TAN were 19.79, 10.39 and 5.06 mg L-1, the 96-h LC50 of NH3 were 1.00, 0.70 and 0.44 mg L-1 at 18, 22 and 26 degrees C respectively. The safe levels of NH3 for A. regius was estimated to be 0.10, 0.07 and 0.04 mg L-1 at 18, 22 and 26 degrees C respectively (P < 0.05). This study clearly indicates that A. regius is more sensitive to ammonia than other marine fish species cultured on the Mediterranean and Eastern Atlantic coasts.Mugla Sitki Kocman UniversityMugla Sitki Kocman University [2015/010]This study was approved by the local ethics committee for animal experiments of Adnan Menderes University (Approval number: 64583101/2014/062). The authors thank Kilic Holding and their employees, in particular Adalet Ucal, Cengiz Onder and Huseyin Serdar. This study was financed with funding from the Scientific Research Projects of Mugla Sitki Kocman University (Project No: 2015/010)
Effect of Temperature on Acute Toxicity of Nitrite to Meagre, Argyrosomus regius (Asso, 1801)
No full textWOS: 000362435500010Meagre, Argyrosomus regius, is a candidate marine fish species for aquaculture diversification, presenting a high economic value in the Mediterranean. Tolerance of juvenile meagre to nitrite (NO2-N) was determined relating to temperature. Fish (3.2 +/- 0.6g and 5.4 +/- 0.9cm) were exposed to different NO2-N concentrations in a series of acute toxicity tests by the static renewal method at three temperatures (18, 22, and 26C) at a pH of 8.0. Low temperature clearly increased tolerance to NO2-N (P<0.05). The 96-h median lethal concentration (LC50) values of NO2-N were 177.63, 139.55, and 49.61mg/L, at 18, 22, and 26C, respectively. The safe levels of NO2-N for juvenile meagre were estimated to be 17.7, 13.9, and 4.9mg/L at 18, 22, and 26C, respectively (P<0.05). This study indicates A. regius is more sensitive to nitrite than other marine fish species cultured in the Mediterranean.Scientific Research Projects of Mugla Sitki Kocman UniversityMugla Sitki Kocman University [2015/010]The authors would like to give thanks to the Kilic Holding Facility and its employees, especially Adalet Ucal, Cengiz Onder and Huseyin Serdar. This study was approved by the local ethics committee for animal experiments of Adnan Menderes University (Approval number: 64583101/2014/062) and financed with funding from the Scientific Research Projects of Mugla Sitki Kocman University (Project No: 2015/010)
Thermal acclimation capacity and standard metabolism of the Pacific white shrimp Litopenaeus vannamei (Boone, 1931) at different temperature and salinity combinations
No full textIn aquatic environments, rising temperatures reduce the oxygen content of the water while increasing the oxygen demand of organisms. In intensive shrimp culture, it is of great importance to know the thermal tolerance of cultured species and their oxygen consumption since this affects the physiological condition. In this study, the thermal tolerance of Litopenaeus vannamei was determined by dynamic and static thermal methodologies at different acclimation temperatures (15, 20, 25, and 30 °C) and salinities (10, 20, and 30 ppt). The oxygen consumption rate (OCR) was also measured to determine the standard metabolic rate (SMR) of shrimp. Acclimation temperature significantly affected the thermal tolerance and SMR of Litopenaeus vannamei (P 0.01). Litopenaeus vannamei is a species that has high thermal tolerance and can survive at extreme temperatures (CTmin-CTmax: 7.2-41.9 °C) with its large dynamic (988, 992, and 1004 °C2) and static thermal polygon areas (748, 778 and 777 °C2) developed at the above temperature and salinity combinations and resistance zone (1001, 81 and 82 °C2). The optimal temperature range of Litopenaeus vannamei is the 25-30 °C range, where a decrease in standard metabolism is determined with increasing temperature. Given the SMR and optimal temperature range, the results of this study indicate that Litopenaeus vannamei should be cultured at 25-30 °C for effective production
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
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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