22 research outputs found

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

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    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

    Constant Connectivity and Boundary Management Behaviors: The role of Human agency

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    The surge of remote and hybrid work in the post-pandemic era reinforced the blurred boundaries between work and non-work responsibilities. Thus, how people manage the boundaries between work and non-work domains has become more complicated. This study advances the previous studies on constant connectivity by focusing on how employees’ perception of constant connectivity might actualize their boundary management behaviors. Additionally, we concentrated on contextual factors, including IT/internet policies, informal social norms, and work flexibility, to investigate how these factors could influence employees’ perception of constant connectivity. This paper reports a two-phase study. In the first phase, we used sentiment analysis to rank 38 internet use policies of Australian universities for grading their strictness toward ICT/internet use. Next, building on the first phase, we interviewed 28 academics. We identified three perceptions of constant connectivity, including constant connectivity as a resource, a challenge, and a duality. We also found five distinct boundary management behaviors connected to three different perceptions

    Nutritional enhancement of total lipid, n-3 and n-6 fatty acids in Artemia urmiana nauplii by enriching with ICES/30/4

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    Artemia urmiana nauplii were enriched with three different concentrations (100, 200 and 300 ppm) of commercial emulsion, ICES/30/4 during two periods (12 and 24 h) to evaluate the enhancement of its Highly Unsaturated Fatty Acids (HUFAs). This source was selected because of its high concentration of the longest chain HUFA's in the n-3 and n-6 series. When 24-h-old Artemia nauplii were enriched with 100 ppm concentration of ICES30/4 during 12 h enriching period, the docosahexanoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA) contents of the nauplii increased to 0.77, 1.22 and 0.34 and when enriched with 300 ppm during 24 h increased to 5.99, 4.97 and 0.73 mg g(-1) dry weight, respectively. DHA, EPA and ARA in control nauplii were 0.00, 0.82 and 0.61 mg g(-1) dryweight, respectively. Total lipid increased from 16.79% in control group to 20.87% in the treatment ICES30/4 24-300. The results suggest that high amount of emulsion and prolong the enriching period are effective in enriching Artemia nauplii in both DHA and EPA increasingly (p < 0.05) but in other fatty acids, there are differences only among period treatments (p < 0.05) and concentration are not any increasing effective. There are only differences among concentration treatments in total lipid p < 0.05) and enriching period do not show any differences

    A comparative study of proximate composition of Artemia urmiana enriched with different sources and levels of HUFA

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    The nutritional quality of commercially available Artemia strains is relatively poor in Eicosapentaenoic acid (EPA), Arachidonic acid (ARA) and especially Docosahexaenoic acid (DHA). Hence, it is essential and common practice to enrich this live prey with emulsions of special oils. One commercial ICES30/4 (Belgium), Linseed oil as a vegetable oil, Cod liver oil and Sturgeon ovary oil as two animal oils with EPA amounts in these oils were 6.29, 0.03, 11.39, 7.55 and the DHA amounts were 20.90, 0.00, 7.64, 2.76 respectively with three concentrations (100, 200 and 300ppm) during two enrichment periods (12 and 24h) were tested in order to improve the HUFA content, the DHA/EPA ratio and ARA content of Artemia urmiana nauplii. The results showed that Artemia enriched with different levels of vegetable oil and enrichment periods was poor in relation to either HUFA content or DHA/EPA ratio but the fish oils and emulsion resulted in HUFA incorporation. Sturgeon ovary oil caused the poorest DHA/EPA ratio enrichment (0.40 in 300ppm-24h) but the commercial emulsion (ICES30/4) was found as the best for DHA/EPA ratio enrichment (1.20 in 300 ppm- 24h). Cod liver oil (0.53 in 100ppm-24h) can be a good internal source substitute for improving the DHA/EPA ratio enrichment compared to ICES30/4 due to price and availability. As a result, HUFA content was increased with enrichment level 200ppm during 24h. Also, all oil sources improved lipid and protein percentages in A. urmiana nauplii

    Proximate composition and fatty acids profiles of Artemia cysts and nauplii from different geographical regions of Iran

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    Artemia has been widely used in aquaculture as a suitable live food. The presence of highly unsaturated fatty acids is a key factor that determines the nutritional value and marketing of Artemia for shrimp, marine larvae, sturgeon and ornamental fish industries. To determine the variation in nutritional content in cysts, decapsulated cysts and nauplii of Artemia from three different biotopes of Iran, were tested for their protein, lipid, energy, and fatty acid profiles, particularly essential fatty acids. The cysts collected from Urmia, Maharlou and Meighan lakes, were rinsed, processed, decapsulated, hatched and then analyzed for proximate and fatty acid composition using standard methods. Statistical comparisons of the results revealed significant differences not only in proximate composition but also in fatty acid contents (p<0.05). The highest mean (±SD) level of protein (60.5±3.3%), lipid (18.60±1.1%) and energy contents (5448.3±10.4 Kcal/kg) were observed in Instar I nauplii hatched from Urmia Lake cysts, Instar I nauplii hatched from Maharlou Lake cyst and Instar I nauplii hatched from Urmia Lake decapsulated cyst, respectively. The highest content of DHA (0.78 mg/g DW) was observed in nauplii of cysts from Urmia Lake whereas it was around zero in other samples. The highest level of EPA (24.24 mg/g DW) was measured in nauplii from Maharlou Lake decapsulated cysts and the lowest (0.24 mg/g DW) was observed in Urmia lake cysts. The results revealed that the nauplii from decapsulated cysts of Maharlou Lake Artemia contained significantly higher levels of EPA and n-3 HUFA compared to others. Therefore, it is recommended to use it in aquatic larviculture

    Laboratory culture of Artemia urmiana using Isfahan province drainages

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    Esfahan province is located in center of Iran at 51° 31 ' E and 33° 29 ' N with area near 15745 Km^2 that consists of 9 percent of the country. According to cilianinof scale it enjoys an arid climate. The mean annual precipitation is equal to 135 mm. Average annual temperature is 16.8°C and mean annual evaporation is 2435 mm in Gavkhoni catchment's area. It has several drainages channels such as north and south rodashtain, segzi drainage, main drainage of water supply organization channel, fender drainage, main drainage, Marchi class II drainage and other drainage channels. Their waterdebi volume is equal to 900l/s. Also, their water can not use for agriculture, drinking and industrial purposes due to high salinity. This study was concluded to optimal use of these water resources aiming at possibilities of culture and propagation of Artemia from Urmia Lake. In this study, physicochemical factors analysis of water, the climate profile, and fauna and flora of the region were identified and determined. In rodashtain region drainages, 2 sites in varzaneh and Sian drainages from gavkhoni wetland limitation were chosen and studied. Water samples in 50-100 liter volumes were taken from their run off waters with 3 replicates. Artemia cysts were hatched under standard laboratory condition according to Lavens and Sorgeloos, 1996). Cyst hatching was carried out in 1.5 liter conical zooks 2 g of Artemia cyst per one liter of drainage water was added to each treatment together with one evidence. Hatching percentage and hatching efficiency were determined. Hatching percentage and hatching efficiency after 76 hours were equal to 55±10 percent and 92000±1200 Nauplii/g cyst in the evidence with tap water and 27±5 % and 31000±1000 in varzaneh drainage water and 13±5 % and 11000±1000 in Sian drainage waters, respectively. Then, all hatched nauplii were cultured in 3 aquarium containing each 100 liters together with one evidence with 3 replicates containing 50 liters in each aquarium in laboratory. Nauplii were fed using a suspension with rice bran, Dunaliella and Naunochlorepsis with density of 2 ×10^ 6 cell/ml. The growth of Artemia Nauplii was slow at the first week of culture and then continued with suitable norm and lower mortality until maturation. The mean size of Nauplii length reached to 9 mm after 2 weeks. Their fecundity was 50 cyst per female. The drainage waters of studied sites can be used as a suitable water source at semi- industrial Artemia production pilot in the region

    Improvement of black tilapia (Oreochromis niloticus) diets with replacement of low-cost, native materials

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    Fish meal production has been fixed in the world because of a limitation in fish stocks. On the other hand, demand of fish meal is growing daily and consequent the cost, too. Therefore, attention to the other protein sources is nessesary. Some plant protein sources, especially oilseeds, have valuable potentials for replacing fish meal because of relative high production in the world and Iran and low cost. According to existing information and availability, cottonseed meal and canola meal were selected as oilseeds; and Azolla was considered whether to be controlled in north provinces of Iran as weed. Growth indices (WG and SGR), food (FCR) and protein efficiency (PER and PCE) of fingerling Nile tilapia Oreochromis niloticus were evaluated in 3 synchronous examinations with 12 treatments and 36 replications. Groups of control, canola meal (at rates of 25, 50, 75 and 100%), cottonseed meal (at rates of 15, 25, 35 and 45%), as the replacements of expensive protein sources (fish meal and soybean meal), and azolla (at rates of 13, 21 and 29% of diet) were studied. Growth indices, total food intake and protein intake of control group were higher than all diets contained plant protein sources. They decreased with plant protein increasing in every grous, separagely (p0.05) between control and canola meal (at rates of 25 and 50%), cottonseed meal (at rates of 15, 25 and 35%) and azolla (at rates of 13 and 21%). All plant protein ingredients were unpalatable, and consequent total food intake, protein consumption and growth decreased. It will be expected that Canola meal and cottonseed meal replace expensive protein sources at the rates of 50 and 35% respectively, and azolla use at the rate of 21% in diets If the problem in palatability solves

    Effect of nutritive microalgae on growth and survival rates, nutrition value and reproduction performance of Artemia urmiana

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    Artemia is the most widespread live food used in the production of different stages in many aquaculture organisms. It is a non-selective filter feeding organism. Generally, microalgae are the most favorable feeds for Artemia, particularly when the algal species have suitable size, digestibility and nutrient values. This study was performed to compare the efficiency of three microalgae namely Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chlorella sp., Cheatocerus sp., Spirolina sp. and Isochrices sp. on the growth, survival and reproduction efficacy in Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to the standard method. Live microalgae were cultured using the Walne and F/2 Guillard's culture mediums. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. Length growth of A. urmiana was measured by Motic SMZ- 168 stereomicroscope equipped by Motic MLC- 150c apparatus and related software in three-day intervals. To determine reproduction efficiency characteristics such as cysts and nauplious production, intervals between two successive reproductions, first reproduction time and the date of female Artemia were analyzed. Statistics analysis was performed by one-way variance (ANOVA) and Duncan test in SPSS 18 software. The results indicated a significant difference (p < 0.01) among three microalgae in terms of length growth, survival rates and reproduction characteristics in A.urmiana. On the other hand, there was a direct relationship between Artemia length growth and reproductive characteristics. In general, this study showed that survival rate, length growth and reproductive characteristics of A.urmiana fed by Dunaliella tertiolecta were significantly higher than A.urmiana fed by other microalgae.Therefore, it seems that Artemia culture in salt water with Dunaliella as natural flora is a suitable choice

    Manufacture of artificial diet to feeding of western white shrimp (Litopenaeus vannamei) in larval stages and in comparison with import diet

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    For the accomplish of project, nine treatments with three replicate in each treatment, used as follows. Control treatment: Feeding with natural foods (Chaetoceros sp and artemia nauplii) Treatment 1: Feeding with combination of inner artificial diet and natural foods. Treatment 2: Feeding with combination of imported artificial diet and natural foods. Treatment 3: feeding from zoea 1 to mysis 1 with chaetoceros sp and from mysis 1 to pl15 with inner artificial diet. Treatment 4: feeding from zoea 1 to mysis 1 with chaetoceros sp and from mysis 1 to pl15 with imported artificial diet. Treatment 5: feeding from zoea 1 to pl15 with project artificial diet. Treatment 6: feeding from zoea 1 to pl15 with imported artificial diet. Treatment 7: Feeding in zoeal stages with chaetoceros sp and from mysis 1 to pl15 with chaetoceros sp+artemia nauplii+ imported artificial diet. Treatment 8: Feeding in zoeal stages with chaetoceros sp and from mysis 1 to pl15 with chaetoceros sp+artemia nauplii+ project artificial diet. Larvae stocked at a density of 100 nauplii/ L-1 (1000 nauplii in each tank each tank), at the beginning of culture period The results showed that, in treatments 1, 2, 7 and 8 from zoea 1 to pl15, growth indexes were suitable and noticible, and in most treatment better than control treatment. Survival percent, in pl15 in treatment 1, 2, 7 and 8 was more than control treatment, and differention between treatment 1, 2 and 8 in comparision with control treatment was statictically significant (p0.05). But thereafter, significantly decresed. In treatments 3 and 4 from zoea 1 to late mysis 3 stage, survival percent in comparision with other treatments were suitable, and thereafter, significantly decreased, and with statictically significant with other treatments (p0.05), but in treatment 8, was more than other treatments. The mean of final length between treatments 1, 2, 6, 7, 8 and in comparision with control treatment, were not statistically significant (p>0.05). But in treatment 2, more than control treatment, and in other treatments less than control treatment

    Study of possibilities of replacement of fish meal by poultry by product in formulated diet of Huso huso

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    To regard to dramatic decreasing of pelagic fish and depending on fish meal for sturgeon Feeding a project with title on "Study of possibility of replacement of fish meal by poultry by product in formulated diet of Huso huso" in two faz (fingerling) and (Growth out) were carried out. In first faz, proximate composition of fish meal, poultry by product and diet ingredient were determined , thereafter Six test diets (contain 45% protein and 19 Mj kg^-1 energy) were prepared based on anchovy fish meal and poultry by-product substituted at levels of 20% (PBM_20), 40% (PBM_40), 60% (PBM_60), 80% (PBM_80) and 100% (PBM_100), respectively. Huso huso Fingerlings (28.42±0.17gr ± SD) were stocked in 18 fiberglass tanks and fed to satiation to eight week. Result indicated the highest final weight (FW), Weight gain (WG), Specific growth rate (SGR) and Protein efficiency ratio (PER) were belonged to control diet (350.52 ±21.86_gr),(1133.00 ±74.84%),(3.74±0.092 %per day) and (1.58 ±0.017) respectively. But No significant difference was detected between FM, PBM_20, PBM_40 and PBM_60 (P>0.05), Also, there were not significant difference in treatments for Feed efficiency Ratio between (PBM_0), (PBM_20), (PBM_40), (PBM_60) (PBM_80) respectively (P0.05).The best feed efficiency ratio belonged to fish fed PBM_40 that no significant differences with (PBM_20), (PBM_60) and (PBM_80) (P>0.05).a significant decrease of body lipid observed by increasing of supplementation of poultry by product in diets that lowest body lipid (6.6±0.16) were stabilized in (PBM_80) (P0.05). also hepatosomatc index were significantly increase by increasing of poultry by product in diets respectively that highest were observed in fish fed PBM100 (4.2±0.63) (P<0.05).Result of this investigation indicated that poultry by product had high potential for replacing of fish meal in fingerling and growth out Huso huso diet. Therefore suggested a investigation design for research about the effect of poultry by product on growth rate, body composition and immune system of Huso huso at long period for introduce a new replacer product Instead Of fish meal in sturgeon aquaculture industry
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