نتایج جستجو برای: food structure

تعداد نتایج: 1816144  

M.A. Mohammadifar, N. Mollakhalili Meybodi,

Extracellular polymeric substances are defined as high molecular weight compounds secreted by the microorganisms in the surrounding area. Since these extracellular substances are mainly polysaccharide, they are named exopolysaccharide. Microbial exopolysaccharides composed of sugar residue have growing interest as a new class of microbial products which can be used in food, pharmaceutical, and ...

2011
Marta Coll Allison Schmidt Tamara Romanuk Heike K. Lotze

Seagrass beds provide important habitat for a wide range of marine species but are threatened by multiple human impacts in coastal waters. Although seagrass communities have been well-studied in the field, a quantification of their food-web structure and functioning, and how these change across space and human impacts has been lacking. Motivated by extensive field surveys and literature informa...

Journal: :Ecology letters 2008
Neil Rooney Kevin S McCann John C Moore

Ecologists have long searched for structures and processes that impart stability in nature. In particular, food web ecology has held promise in tackling this issue. Empirical patterns in food webs have consistently shown that the distributions of species and interactions in nature are more likely to be stable than randomly constructed systems with the same number of species and interactions. Fo...

2012
Benjamin Baiser Nicholas J. Gotelli Hannah L. Buckley Thomas E. Miller Aaron M. Ellison

Aim The network structure of food webs plays an important role in the maintenance of diversity and ecosystem functioning in ecological communities. Previous research has found that ecosystem size, resource availability, assembly history and biotic interactions can potentially drive food web structure. However, the relative influence of climatic variables that drive broad-scale biogeographic pat...

Journal: :تحقیقات مالی 0
محمد حسین ستایش استادیار گروه حسابداری دانشگاه شیراز، ایران فرهاد کاشانی پور کارشناس ارشد حسابداری، دانشگاه شیراز، ایران

the aim of this research is the investigation the relationship between the capital structure and institutional ownership mid to the other effective factors on this relation in tehran stock exchange. the others factors include the percentage of stock dividend, profitability, business risk, assets structure, liquidity, growth, and company size. the statistical population of the research is 117 li...

Journal: :PLoS Biology 2006
Nicholas J Gotelli Aaron M Ellison

Plant and animal population sizes inevitably change following habitat loss, but the mechanisms underlying these changes are poorly understood. We experimentally altered habitat volume and eliminated top trophic levels of the food web of invertebrates that inhabit rain-filled leaves of the carnivorous pitcher plant Sarracenia purpurea. Path models that incorporated food-web structure better pred...

2009
Mary I. O'Connor Michael F. Piehler Dina M. Leech Andrea Anton John F. Bruno

Climate change disrupts ecological systems in many ways. Many documented responses depend on species' life histories, contributing to the view that climate change effects are important but difficult to characterize generally. However, systematic variation in metabolic effects of temperature across trophic levels suggests that warming may lead to predictable shifts in food web structure and prod...

2015
Abigail Z. Jacobs Jennifer A. Dunne Cristopher Moore Aaron Clauset

Food webs represent the set of consumer-resource interactions among a set of species that co-occur in a habitat, but most food web studies have omitted parasites and their interactions. Recent studies have provided conflicting evidence on whether including parasites changes food web structure, with some suggesting that parasitic interactions are structurally distinct from those among free-livin...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی امیرکبیر(پلی تکنیک تهران) - دانشکده مهندسی شیمی 1386

در کار اخیر با استفاده از روش رویه پاسخ و روش آماری مکعب مرکزی رابطه ریاضی چند جمله ای درجه دو بین درجه جانشینی اکتنیل سوکسنیک انیدرید روی نشاسته ذرت و شرایط واکنش با توجه به سه فاکتور قابل کنترل دما، زمان، و ph بدست آمده است. همچنین ساختار شیمیایی نشاسته سوکسنیله توسط طیف سنجی ft-ir ررسی شده و برای مشاهده ساختار سطحی مولکول نشاسته سوکسنیله تصاویر میکروسکوپ الکترونی گرفته شده است. پایداری ام...

Journal: :thrita 0
mohammad rezaei department of food safety and hygiene, school of public health, tehran university of medical sciences (tums), tehran, ir iran fatemeh safar abadi department of veterinary, arak university of applied sciences, arak, ir iran zahra sharifi department of veterinary, arak university of applied sciences, arak, ir iran fereshteh karimi department of food safety and hygiene, school of public health, tehran university of medical sciences (tums), tehran, ir iran mahmood alimohammadi department of environmental health engineering, school of public health, tehran university of medical sciences (tums), tehran, ir iran; department of environmental health engineering, school of public health, tehran university of medical sciences (tums), tehran, ir iran. tel: +98-2188954911, fax: +98-2188950188 ruh allah susan abadi department of veterinary, arak university of applied sciences, arak, ir iran

conclusions considering the high level of artificial colors found in the samples of this study, preventive measures are essential. results the results showed that several products did not meet the standards. fifty-six out of the 70 (80%) samples examined in the study, namely sunset yellow (60%), tartrazine (57.1%), quinoline yellow (44.28%), azorubine (28.57%), ponceau 4r (8.57%) and allura red...

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