Groups having complete bipartite divisor graphs for their conjugacy class sizes

Given a finite group G, the bipartite divisor graph for its conjugacy class sizes is the bipartite graph with bipartition consisting of the set of conjugacy class sizes of G-Z (where Z denotes the centre of G) and the set of prime numbers that divide these conjugacy class sizes, and with {p,n} being an edge if gcd(p,n)\neq 1. In this paper we construct infinitely many groups whose bipartite divisor graph for their conjugacy class sizes is the complete bipartite graph K_{2,5}, giving a solution to a question of Taeri.Comment: 5 page

Social Media in Practice: How Configurations of Affordances Change Business Practices

This paper aims to explain how configurations of affordances of social media and mobile technologies change and shape business practices. The study draws upon the concept of affordances and the more recent perspectives around it that emphasises the practice lens. The concept of affordances has been used to explain the entanglement of the social and the material. However, the recent theoretical works around the concept suggest that the study of affordances should go beyond the affordances of a particular technology in a specific situated context. In this regard, this paper focuses on the configurations of affordances based on a framework proposed by Lindberg and Lyytinen (2013). The findings based on ethnographic and netographic observations, in this stage of the research, suggest that the ‘organisation domain’ plays an important role in how the ‘infrastructure domain’ puts into practice as the community of businesses shape their social media practices

Nutritional value of Chabahar Bay (Oman Sea) Sargassum lentifollium before and after monsoon season

The proximate composition of brown seaweed Sargassum lentifollium was investigated in this study along with analysis of some physicochemical parameters of Chabahar Bay water. The relationship between the nutritive components of this species and environmental parameters was established. Crude protein content varied from 8.05±1.15% of dry weight to 12.29±1.10%, carbohydrate from 31.11±2.03% to 25.11±2.13%, humidity from 15.21±1.00% to 19.22±1.11% with differences significantly before and after monsoon seasons, respectively while ash content varied from 26.11±2.43% to 24.11±1.40%, total fat from 2.11±0.43 % to 1.80±0.40% , total fiber from 10.34±2.21% to 11.84±0.33% and astaxantin content (ppm) from 104.11±1.00 to 97.20±1.18 before and after monsoon season respectively without any significant differences(P>0.05). Regarding to physicochemical parameters of sea water, the result showed there are differences between salinity, dissolved oxygen, water temperature, nitrate, phosphate, chlorophyll a and c before and after monsoon season significantly while there are not in pH, silicate and chlorophyll b. Statistical analysis computed among the environmental and biochemical parameters suggested the potential role played by the abiotic parameters on biosynthetic pathways of seaweed

Affordance Theory in Social Media Research: Systematic Review and Synthesis of the Literature

Social media technologies continue transforming various dimensions of social and organisational life through possibilities they present for goal-oriented actions of diverse users/ user groups. The notion of affordances that explains these possibilities has witnessed popularity among IS scholars to study these technologies. However, since the concept itself has been under ongoing development, its use in studying social media technologies has been focused on identifying technical affordances, perception and actualisations of these affordances, or the social and organisational implications of such affordances. In this research-in-progress paper, we present our attempt to systematically review and synthesise the literature to examine the effects of social media affordances. In addition, we aim to systematically review the existing literature to explore how the concept of affordance has been employed in social media research, to uncover the effects of social media affordances and present a comprehensive framework of these affordances effects and identify areas for future research

Integrated culture of white leg shrimp (Litopenaeus vannamei) with different densities of Nile tilapia (Oreochromis niloticus) in recirculation system

Recirculation water system in shrimp culture with objective of decline waste materials of culture media and decreasing the disease is one of strategy which helping the shrimp production. In this investigation, effects of different densities of Nile tilapia (Oreochromis niloticus) culture with white leg shrimp (Litopenaeus vannamei ) on growth, nutrients conversion rate (nitrogen and phosphor) of shrimp biomass and production economy in recirculation system were studied. Economical efficiency obtained according to final harvested biomass (shrimp and tilapia), the price and other costs for each treatment. Experiments were done in tanks with 6 treatments including: Culture shrimp with exchanged water (T1), culture shrimp with recirculated water system (T2) and integrated culture of shrimp with different densities of tilapia (T3- 0.01, T4- 0.025, T5- 0.05 and T6- 0.075 shrimp- tilapia ratio). The density of shrimp in all treatments was constant about 40/m2. Shrimps were fed with commercial food pellet for 8 weeks. Tilapia was not fed during 7 weeks of experiment. Growth rate and total production of shrimp in T2 compared to that of T5 and T6 and results showed significant differences. No significant differences were detected with other treatments. Growth rate in T3 significantly increased compared to other treatments. Nitrogen conversion rate of biomass (tilapia and shrimp) in all treatments except T1 statistically demonstrated an increasing rate as the tilapia-shrimp ratio was increased. Phosphor conversion ratio of biomass (tilapia and shrimp) showed an increment in T3, T4, T5 and T6 and was significantly different with T1 and T2. Production economy in T2 followed by T4 was significantly increased compared with other treatments. The lowest economical efficiency obtained in T5 and T6 and the highest found in T2. The results of present study suggest that in integrated culture system (tilapia-shrimp), increasing tilapia densities may have a direct significance effect on phosphor conversion rate improvement and an inverse effect on nitrogen conversion and shrimp growth rates. Regarding to studied parameters, decreasing the tilapia- shrimp ratio (0.01 and 0.025) increased nitrogen conversion rate with no decrease in shrimp growth rate

Effects Of Artemia Urmiana Enrichment In Larviculture Of Persian Sturgeon (Acipenser Persicus) Effects Of Artemia Urmiana Enrichment In Larviculture Of Persian Sturgeon (Acipenser Persicus)

The main objective of this study was to improve the Persian Sturgeon, Acipenser persicus survival when they released into the Caspian Sea through the enrichment of its larval food, Artemia urmiana. A series of experiments was conducted to evaluate effect several enrichment methods on the chemical composition of A. urmiana nauplii, larval growth, survival and salinity tolerance of the Persian sturgeon larvae. In the first series of 3 factorial experiment, the effects of oil sources, oil concentration and enrichment periods on the nutritive value of A. urmiana nauplii and growth rate, survival percentage, chemical composition and salinity tolerance of sturgeon larvae fed enriched Artemia and unenriched (as control) were evaluated. The results showed Total n-3 highly unsaturated fatty acid contents, DHA/EPA and ω3/ω6 ratios in Artemia nauplii and sturgeon larvae were significantly increased (P0.05). When the sturgeon larvae were exposed to salinity test, those fed with HUFA enriched Artemia showed tolerance only up to 6 ppt. In the second series of 3 factorial experiment, the effects of oil sources each with 300 ppm concentration, ascorbyl palmitate levels and enrichment periods on the nutritive value of A. urmiana nauplii and growth rate, survival percentage, chemical composition and salinity tolerance of sturgeon larvae fed enriched Artemia and unenriched (as control) were evaluated. The results showed vitamin C contents were increased in both Artemia and fish larvae significantly (P0.05). Survival rates and chemical compositions were significantly improved (P<0.05) in fish larvae fed Artemia enriched HUFA oil supplemented with AP. The ICES30/4 was the best oil source for improving the chemical composition including fatty acids in the larvae when it was supplemented with vitamin C. Lower levels of vitamin C (less than 30%) and longer enrichment period (24 h) were more effective (P<0.05) in improving the chemical composition of sturgeon fish larvae. When the sturgeon larvae were exposed to salinity test, those fed with HUFA +AP enriched Artemia demonstrated high tolerance (≥ 90% survival) up to 12 ppt for 120h. Although the enrichment of Artemia urmiana with 300 ppm ICES30/4 and 30% vitamin C gave the best salinity tolerance at 12ppt (100±0.00 % survival), the enrichment with 300 ppm sturgeon ovary oil and 10% vitamin C was economically affective in increasing the salinity tolerance of Persian sturgeon larvae (95±2.00 % survival)

‘Affordance’ - what does this mean? (4)

The growing use of the concept of an affordance raises questions about its meaning and has led to much debate. This exploratory evaluation of usage reveals divergent meanings, exposes tensions and explains why there is confusion about the concept. The notion of an affordance focuses attention upon possible action, raising the issue of how affordances give rise to action. The discussion reveals latency in the nature of affordances, that they do not exist in isolation, can be designed into artefacts and have social, temporal and spatial dimensions for their actualization. An affordance is a necessary condition for its enactment, but sufficiency arises with the situatedness of enactment. Moreover, an affordance, which is actualized through its enactment, is thus performative. It is concluded that the term affordance should be used with caution and with more precision and rigour, as its everyday use is fraught with vagueness saying little about the complex dynamics that underpins affordance as a concept

ADOPTING A ‘SEARCH’ LENS IN EXPLORATION OF HOW ORGANISATIONS TRANSFORM DIGITALLY

As new forms of digital technologies continue to proliferate, Information Systems (IS) scholars argue that we are witnessing a paradigmatic shift in the nature of technologies and their potential in profoundly changing organisations and ways of working. Such technological shifts have also given rise to consumerisation of IT and thus creating more endowed consumers with changing expectations and practices. The black-boxed nature of digital platforms and their algorithms have imposed challenges for scholars to understand these changes. In this paper, we draw on the notion of ‘search’ and its use in the organisation and management literature to propose a new analytical approach in studying digital transformations. Unlike the existing use of search in enhancing organisational performance or introducing new products, we use search as an approach that organisations renew their offerings, processes and practices in redefining their value proposition. Through different reconfigurations of material enactments, search becomes the underlying logic of organising and the centralised control shifts to a de-centralised autonomy, which facilitates the ongoing adaptations of practices as organisations transform digitally

AFFORDANCE THEORY IN SOCIAL MEDIA RESEARCH: SYSTEMATIC REVIEW AND SYNTHESIS OF THE LITERATURE

Social media technologies continue transforming various dimensions of social and organisational life through possibilities they present for goal-oriented actions of diverse users/ user groups. The notion of affordances that explains these possibilities has witnessed popularity among IS scholars to study these technologies. However, since the concept itself has been under ongoing development, its use in studying social media technologies has been focused on identifying technical affordances, perception and actualisations of these affordances, or the social and organisational implications of such affordances. In this research-in-progress paper, we present our attempt to systematically review and synthesise the literature to examine the effects of social media affordances. In addition, we aim to systematically review the existing literature to explore how the concept of affordance has been employed in social media research, to uncover the effects of social media affordances and present a comprehensive framework of these affordances effects and identify areas for future research