نتایج جستجو برای: low and high fish
تعداد نتایج: 17216273 فیلتر نتایج به سال:
With the increasing use of water resources, increasing population, urbanization, identification and conservation of aquatic ecosystems have received much attention. To this end, researchers consider the use of remote sensing techniques and GIS to be appropriate and efficient. In this study, habitat susceptibility of fish to the Choghakhor wetland in the central plateau of Iran was investigated....
Determining the optimal culture density is necessary to improve fish performance and profitability. A total of 1350 rainbow trout with an average initial weight of 30±1.5 g were obtained. Then, the fish were randomly distributed in 12 fiberglass tanks and reared at densities of 15, 30, 45 and 60 kg/m3 for 60 days. The final weight, weight gain, and protein efficiency ratio were significantly hi...
The northern tuna stocks in the Pacific have specific characteristics: long-term large variability of the total biomass, sparse stock-recruitment relationship, and no obvious indication of recruitment overfishing even though the spawning stock biomass sometime fell into in a very low level. In contrast, southern stocks in the Pacific have one way decreasing trends in shorter exploitation histor...
in this study, three stations of the north persian gulf were analyzed in order to determinethe effect of trophic levels on the concentration of harmful pahs in fish and sediment. in all cases,similar distributions were observed in which benzo(a)pyrene largely predominated andbenzo(b)fluoranthene and pyrene were the second major compounds in fish tissues. the predominantcomponents of pahs in sed...
according to research, academic self-concept and academic achievement are mutually interdependent. in the present study, the aim was to determine the relationship between the academic self-concept and the academic achievement of students in english as a foreign language and general subjects. the participants were 320 students studying in 4th grade of high school in three cities of noor, nowshah...
saluk mount is selected for devonian biostratigraphy. this area located at southwest of bojnurd. in this study three sections are selected and two sections, chahar-borj and tabar sections with a thickness of 650 m, which consist mainly of calcareous sediments was studied in detailed but third section, qelli section, with a thickness of about 450m which consist mainly of sandstone and evaporates...
teachers’ beliefs greatly influence their performance in the classroom, their choice of instructional strategies, their way of controlling the class, their dealing with the students, and their general goals and objectives. one of these beliefs is teachers’ sense of efficacy which is viewed as an important construct and has shown to be positively correlated with students’ achievement (ross, 1992...
چکیده: پژوهش حاضر به بررسی تطبیقی اعتماد اجتماعی در بین دبیران زن و مرد مقطع راهنمایی شهر ایلام می پردازد. امروزه در جوامع شاهد گسترش ارتباطات هستیم و با توجه به این که دامنه کنش های اجتماعی از حد روابط با آشنایان و دوستان فراتر رفته و به تعامل با کنشگران غربیه و نا آشنا گسترش یافته است، لزوم وجود اعتماد، بیش از پیش احساس می شود. اما با توجه به نقش دبیران در نهادهای آموزشی، در انتقال ارزش ها و...
in this work, a novel and fast method for direct analysis of volatile compounds (davc) of medicinal plants has been developed by holding a filament from different parts of a plant in the gc injection port. the extraction and analysis of volatile components of a small amount of plant were carried out in one-step without any sample preparation. after optimization of temperature, extraction time a...
Since the consumption is the main target of production and desired items of manufactures must be in the same direction with consumer demands through seller, evaluation of purchase and sale trends have specially importance. Therefore, this study was conducted in 1393 in order to evaluate the purchase and sale trend in the fish market of Guilan province’s in Bandar Anzali, Astara, and Kiashahr po...
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