نتایج جستجو برای: گاوماهی شنی neogobius fluviatilis pallasi
تعداد نتایج: 2466 فیلتر نتایج به سال:
The tendency of many species to abandon migration remains a poorly understood aspect of evolutionary biology that may play an important role in promoting species radiation by both allopatric and sympatric mechanisms. Anadromy inherently offers an opportunity for the colonization of freshwater environments, and the shift from an anadromous to a wholly freshwater life history has occurred in many...
زمینه و هدف: به دلیل سمیت عناصر مس و روی، حذف این فلزات با استفاده از روش های کم هزینه و در عین حال موثر امری ضروری است. این آزمایش به منظور بررسی تاثیر فیلتر تند شنی تک لایه ثقلی بر کارایی حذف فلزات سنگین روی و مس در محیط آبی با حضور غلظت های متفاوت فسفات اانجام گردید.روش بررسی: این مطالعه یک فیلتر تند شنی تک لایه ثقلی با محیط شن سیلیسی را به کار برده است. آزمایش ها برای تمامی حالات غلظت های 2...
Non-indigenous species (NIS) can impact marine biodiversity and ecosystem structure and function. Once introduced into a new region, secondary dispersal is limited by the physiology of the organism in relation to the ambient environment and by complex interactions between a suite of ecological factors such as presence of predators, competitors, and parasites. Early prediction of dispersal poten...
Invasion biology research has identified two juxtaposing behavioural traits, aggressiveness and sociality, that may both increase the success of species invasions. Highly aggressive invaders can out-compete native species for resources, while social gregarious invaders can tolerate high conspecific density. In order to tease apart the effects of aggressive versus social tendencies on the succes...
پایان نامه حاضر ابتدا به تعریف بهسازی و لزوم آن و انواع روشهای بهسازی خاک بصورت اجمالی می پردازد. آنگاه روش ستون شنی بعنوان یکی از روشهای رایج بهسازی خاک تشریح وکاربردها، مزایا و محدودیتهای این روش توضیح داده می شود. نیز چگونگی طراحی و انواع محتمل نحوه خرابی ستون شنی براساس آیین نامه تهیه شده توسط موسسه آزاد راههای آمریکا (fhwa) توضیح داده می شود. با مطالعه موردی استفاده از این روش در پروژه مو...
Pacific herring Clupea pallasi immunoglobulin is an IgM-like molecule comprised of heavy and light chains with molecular weights of 79 and 25 to 27 kD, respectively. Purified immunoglobulin was used to generate highly specific polyclonal antibodies for development of a sandwich ELISA. The ELISA was used to quantify total plasma IgM in 602 Pacific herring captured in Prince William Sound and Sit...
Simultaneous trawling at surface and at depth at one location off the Columbia River, Oregon, in June 2000 identified the depth distribution of juvenile salmonids and associated fishes. Juvenile salmon off the Columbia River were distributed primarily near the surface, within the upper 12 m. Highest densities of subyearling chinook salmon (Oncorhynchus tshawytscha) off the Columbia River were a...
The widespread occurrence and accumulation of plastic waste in the environment have become a growing global concern over the past decade. Although some marine organisms have been shown to ingest plastic, few studies have investigated the ecological effects of plastic waste on animals. Here we show that exposure to environmentally relevant concentrations of microplastic polystyrene particles (90...
The New World tyrant-flycatcher (Tyrannidae) Attila rufus (Vieillot, 1819) is commonly known as grey-hooded attila or 'capitão-de-saíra' in Brazil (Sick 1997; CBRO 2014). This species has a wide distribution and their population trends appear to be stable; therefore, it is least concern according to IUCN (2015) criteria.
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