482 research outputs found

    Mutual interaction of salinity and dietary protein level on growth, survival and body composition of narrow clawed cray fish (Astacus leptodactylus)

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    In this study Astacus leptodactylus were tested for 8 week with three practical diets containing three crude protein (30, 35 and 40%) and isoenergetic level (370kcal/100 g) in fresh water and brackish water of Caspian Sea. In this test, 6 treatments were used with three replicates in 18 fiberglass tank (110 liter). Each tank had 5 narrow clawed Cray fish (mean (±SD) individual weight=17±2.3g) and totally 90 clawed Cray fish were stocking. Result indicates mean weight of Cray fish in fresh water and brackish water were 14.82 and 12.73, respectively, that were significantly different. The highest survival occurred in interaction between protein (30%) and salinity (0) (95.55%) and lowest survival occurred in protein 40 – salinity (12) that were significantly different. The highest specific growth rate (SGR), weight gain (WG), Protein Efficiency Ratio (PER), Net Protein Utilization (NPU) and lowest Feed Conversion Ratio (FCR), demonstrated that dietary (protein 30% and fresh water) which had no significantly differences. Result of this study showed that the highest protein of body composition were in practical diet containing 30% protein and 0 salinity (freshwater) that were significantly different with other treatment

    An investigation on feeding habits of northern pike of Anzali Lagoon

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    Northern pike (Esox lucius L.) as a major game fish can be valuable in the management of water resources. In the present study, a total of 152 pikes from four areas: Abkenar (24%), Sorkhankool (10%), Siakeshim (54%) and Sheyjan (12%) were sampled. Female fishes were 75.6% of the samples and males were only 24.4%. Northern pike showed relatively fast growth and fishes above two years of age were mature and reached an average length of 32 cm. Feeding intensity and growth co-efficient in this species were correlated. Growth was highest in the lower age groups and with an increase in age and size, the feeding intensity and growth co-efficient of this have decreased. Northern pike in different ages feeds on different species of fish found in Anzali Lagoon. The most important of these fish species are Carassius auratus, Hemiculter leucisculus, Rhodeus sericeus amarus and larvae of Chalcalburnus chalcoides. In the 0+ age group pike mainly feeds on zooplanktonic Mysids. The results of the present study showed that Northern Pike is not restricting populations of commercial fish species of Anzali lagoon, but on the contrary it plays an important role in biological control of reproduction and propagation of non-commercial species like C. auratus and H. leucisculus

    Core promoter short tandem repeats as evolutionary switch codes for primate speciation

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    Alteration in gene expression levels underlies many of the phenotypic differences across species. Because of their highly mutable nature, proximity to the +1 transcription start site (TSS), and the emerging evidence of functional impact on gene expression, core promoter short tandem repeats (STRs) may be considered an ideal source of variation across species. In a genome-scale analysis of the entire Homo sapiens protein-coding genes, we have previously identified core promoters with at least one STR of ≥6-repeats, with possible selective advantage in this species. In the current study, we performed reverse analysis of the entire Homo sapiens orthologous genes in mouse in the Ensembl database, in order to identify conserved STRs that have shrunk as an evolutionary advantage to humans. Two protocols were used to minimize ascertainment bias. Firstly, two species sharing a more recent ancestor with Homo sapiens (i.e. Pan troglodytes and Gorilla gorilla gorilla) were also included in the study. Secondly, four non-primate species encompassing the major orders across Mammals, including Scandentia, Laurasiatheria, Afrotheria, and Xenarthra were analyzed as out-groups. We introduce STR evolutionary events specifically identical in primates (i.e. Homo sapiens, Pan troglodytes, and Gorilla gorilla gorilla) vs. non-primate out-groups. The average frequency of the identically shared STR motifs across those primates ranged between 0.00005 and 0.06. The identified genes are involved in important evolutionary and developmental processes, such as normal craniofacial development (TFAP2B), regulation of cell shape (PALMD), learning and long-term memory (RGS14), nervous system development (GFRA2), embryonic limb morphogenesis (PBX2), and forebrain development (APAF1). We provide evidence of core promoter STRs as evolutionary switch codes for primate speciation, and the first instance of identity-by-descent for those motifs at the interspecies level. © 2014 Wiley Periodicals, Inc

    Evaluation of different dietary protein and energy levels on growth performance and body composition of narrow clawed crayfish (Astacus leptodactylus)

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    Nine practical diets containing increasing percentages of crude protein (CP) and energy (30%, 35%, 40% and 300kcal/100g, 370kcal/100g and 450kcal/100g) were fed to narrow clawed crayfish (mean individual weight=17±2.3 g) during an 8 week feeding trial. Weight Gain, Feed conversion ratio (FCR), Protein Efficiency Ratio (PER), Net Protein Utilization (NPU), Daily Food Consumption (DFC) and body composition of tail-muscle meat of narrow clawed crayfish were determined. At the conclusion of the experiment, comparing the growth parameters in response to interaction between protein and energy levels demonstrated that dietary number 2 (30/370) resulted in higher WG, NPU, PER, and the lowest FCR whereas dietary number 3 (30:450) showed higher SGR and DFC. Comparison of the body composition results indicates the greatest amount of protein absorption in diet number 2 (30/370). Results from this study indicate that narrow clawed crayfish can be fed a practical diet containing 30% protein and 370 Kcal/100gr. Reducing CP levels in narrow clawed crayfish diets may help reduce operating costs and thereby increase producers’ profits

    Sustainable high strength steel flush end plate beam-tocolumn composite joints with deconstructable bolted shear connectors

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    The design of engineering structures for deconstructability can reduce the energy and cost required for their demolition and the disposal of their construction waste, and it also enhances the sustainability of a building by allowing for easy dismantling and the reuse or recycling of structural components and construction materials at the end of the service life of the building. In addition, using high performance materials such as High Strength Steel (HSS) can improve the sustainability of a structure by providing for higher design stresses and accordingly reducing the self-weight of the structure. This paper describes the results of four full-scale beam-to-column deconstructable composite joints with HSS S690 flush end plates. The structural behaviour of the new system in conjunction with application of post-installed friction-grip bolted shear connectors for developing deconstructable composite floors is investigated. The test results show that the proposed composite beam-tocolumn joints can provide the required strength and ductility according to EC3 and EC4 specifications, and that the system can be easily deconstructed at the end of the service life of the structure as a proof of concept

    Identification and Prioritization of Energy Consumption Optimization Strategies in the Building Industry Using the Hybrid SWARA-BIM Model

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    Energy consumption in buildings has become one of the most critical problems in all countries and principles of sustainability suggest that a satisfactory solution must be found to reduce energy consumption. This study aims to identify and prioritize energy consumption optimization strategies in buildings. Data collection consists of gather-ing primary data from the existing literature and secondary data from interviews, questionnaires, and simulations through building information modeling (BIM) tools. Twenty-nine strategies were identified and categorized into five groups according to their nature and ranked using one of the multiple criteria decision-making (MCDM) methods called the step-wise weight assessment ratio analysis (SWARA). A case study building in Shiraz, Iran, was simulated using BIM software, and the energy saving potential of the highest ranked strategies were obtained. According to the results, significant contributors to the energy consumption optimization were “Using renewable energy resources,” “Using efficient insulation,” and “Using suitable materials,” providing 100%, 35%, and 23% efficacy, respectively. The results obtained from this study can inform the building industry’s key stakeholders regarding the best strategies to apply in order to reduce energy consumption and improve sustainability in the construction industry

    Performance of bolted connections in deconstructable composite frames

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    The design of engineering structures for deconstructability can reduce the energy and cost required for their demolition and the disposal of their construction waste, and it also enhances the sustainability of a building by allowing for easy dismantling and the reuse or recycling of structural components and construction materials at the end of the service life of the building. In addition, using high performance materials such as High Strength Steel (HSS) can improve the sustainability of a structure by providing for higher design stresses and accordingly reducing the self-weight of the structure. This paper describes the results of four full-scale beam-to-column deconstructable composite joints with HSS S690 flush end plates. The structural behaviour of the new system in conjunction with application of post-installed friction-grip bolted shear connectors for developing deconstructable composite floors is investigated. The test results show that the proposed composite beam-tocolumn joints can provide the required strength and ductility according to EC3 and EC4 specifications, and that the system can be easily deconstructed at the end of the service life of the structure as a proof of concept

    Establishment of Space Syntax to Read Urban Road Network; the Case of Sari, Iran

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    Cities have permanent changes as a living organism, where the transformation required in designing a solution for structural and social demands achieving safe and healthy human contacts. Some scholars divide city sustainable development toward two main views, as the building's set are connected by a space, on the other hand human social actions are linked by urban network interaction. The aim of this paper is to study on urban road network by the establishment of space syntax logic, this issue is divided into two main parts, as a first part, the study on already existing and the second part is bringing the new suggestions to a more qualified urban road network. Sari city of Iran is selected for this Case Study

    Quantifying reputation loss of pipeline operator from various stakeholders perspectives, part 1: prioritization

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    Quantifying reputation loss (RL) due to pipeline damage is commonly generalized based on the owner's definition. This one-way perspective of portraying RL is unfair and unrealistic and consequently miscalculates the impact assessment of pipeline damage; hence, inaccurate risk prediction. It is crucial to develop a model to quantify qualitative RL to avoid unpredicted risk. Thus, this article provides a framework for a procedure to calculate RL by utilizing the factors identified in a previous study. In this paper (Part 1), the prioritization of factors based on the stakeholders' perspectives is presented. The factors were grouped into stakeholder-influenced categories and prioritized by a fuzzy analytic hierarchy process based on the feedback gained from the stakeholders, i.e., investors, customers, employees and the public. The result shows that factor D3, “Accident severity”, was ranked highest by all stakeholders. The priority vector for each factor obtained was assigned as a weight of the factor. The pipeline owner's reputation loss model (RLM) is developed by applying the obtained priority vectors in the subsequent paper (Part 2). The developed model was verified by experts as a comprehensive, clear, objective, practical and moderately reliable model. The model was applied to a case study and eventually produced a lower risk value when compared with the currently used model. It is proven that RL factors can be quantitatively measured and can simultaneously improve pipeline damage impact assessment. Thus, a risk-based inspection schedule can be managed comprehensively

    The performance of a cable-stayed bridge pylon under close-range blast loads

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    Recent bridge collapses have raised an awareness of, and a concern for, the safety and robustness of bridges subjected to blast loading scenarios. The incident pressure generated by the explosion can cause severe structural damage and a loss of critical structural members, resulting in partial collapse of the bridge. Previously, most relevant research effort has been devoted to understanding the response of buildings under blast loading and to develop guidelines to increase the resistance of such structures, while relatively little research attention has been focused on bridge structures. Recent advancements in numerical methods have enabled the viable and cost-effective simulation of complicated blast scenarios, and hence these methods provide a useful reference for safeguarding design and assessment of critical infrastructure. To reduce the computational costs, previous studies on long span bridges under blast loads typically take advantage of sub-structuring techniques, in which only part of the structure is modelled. However, such oversimplifications can lead to erroneous results. Accordingly, this study is an attempt to simulate the dynamic response of an entire cable-stayed bridge subjected to blast loading based on best practice techniques obtained from the literature. The response of a steel bridge, designed according to the minimum requirements of the Australian Standard AS5100, is investigated when subjected to blast loads ranging from small to large explosions at different positions above the deck using numerical simulations. In addition, the potential effects of blast loads on different structural components (i.e. the deck and pylons) are discussed and possible blast mitigation strategies such as the application of FRP and optimization of the geometry of the pylons are investigated
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