نتایج جستجو برای: تصاویر aster

تعداد نتایج: 17887  

2017
John F. Bruno Tatyana A. Rand Nancy C. Emery Mark D. Bertness

Intra- and interspecific interactions can be broken down into facilitative and competitive components. The net interaction between two organisms is simply the sum of these counteracting elements. Disentangling the positive and negative components of species interactions is a critical step in advancing our understanding of how the interaction between organisms shift along physical and biotic gra...

2007

Regional scale geological maps are still not available for many remote parts of the Earth. All geological maps contain two fundamental pieces of information: a) lithological data: a list of the various rock types present, and b) structural data: geometrical information that describes the spatial relationships of the various rock units. For the purposes of regional scale geological mapping the s...

2016
Daniel J. Eck Charles J. Geyer

Precise estimation of expected Darwinian fitness is a central component of life history analysis. Our methods provide precise estimation by incorporating general envelope methodology into the aster modeling framework. This level of precision provided from out methods allow researchers to draw stronger conclusions about the driving forces of Darwinian fitness from their life history analyses tha...

2004
E. H. Mendoza N. C. Silva José dos Campos

The objective of this study is to show the applicability of the genetic synthesis of the unsupervised artificial neural network ART2 (Adaptive Resonance Theory) in the classification of ASTER image for land use/land cover mapping. The area under study is located in northern Mato Grosso State, Brazil, and is characterized by a strong human occupation process, which caused intensive changes at th...

2015
Guo-Jin Zhang Hai-Hua Hu Cai-Fei Zhang Xiao-Juan Tian Hui Peng Tian-Gang Gao Tzen-Yuh Chiang

Aster tianmenshanensis G. J. Zhang & T. G. Gao, a new species of Asteraceae from southern China is described and illustrated based on evidence from morphology, micromorphology and molecular phylogeny. The new species is superficially similar to Aster salwinensis Onno in having rosettes of spatulate leaves and a solitary, terminal capitulum, but it differs by its glabrous leaf margins, unequal d...

Journal: :The Journal of Cell Biology 1985
T E Schroeder D E Battaglia

"Spiral asters" composed of swirls of subcortical microtubules were recently described in fertilized eggs of the sea urchin Strongylocentrotus purpuratus. In our study, these structures did not occur at culture temperatures below 16 degrees C. When the culture temperature was elevated, however, "spiral asters" routinely appeared during a susceptible period before mitotic prophase when the sperm...

Journal: :Development 1992
M M Schroeder D L Gard

Anti-tubulin antibodies and confocal immunofluorescence microscopy were used to examine the organization and regulation of cytoplasmic and cortical microtubules during the first cell cycle of fertilized Xenopus eggs. Appearance of microtubules in the egg cortex temporally coincided with the outgrowth of the sperm aster. Microtubules of the sperm aster first reached the animal cortex at 0.25, (t...

ژورنال: مدیریت بیابان 2017

گرد و غبار یکی از مخاطرات طبیعی است که عمدتاً در مناطق خشک و نیمه‌خشک جهان رخ می‌دهد و به همین دلیل یکی از معضلات اصلی کشور ایران نیز به شمار می‌رود. در این مقاله، به شناسایی کانون‌های بالفعل تولید گرد و غبار در استان البرز با استفاده از تصاویر ماهواره‌ای و مدل‌سازی عددی پیش بینی‌ جریان هوا پرداخته شده است. داده‌های ماهواره‌ای سنجنده OLI لندست 8 (2013 تا 2015) و داده مدل رقومی ارتفاعی سنجنده AST...

2010
Kenneth E. Frost Russell L. Groves Randy Van Haren

Problem Defined: Each year, Wisconsin growers produce carrots on an average of 4200 acres grossing over $6 million dollars in revenues (USDA-NASS, 2007 annual bulletin). Unfortunately, carrot fields are threatened annually by the occurrence of aster yellows phytoplasma (AYp), which is obligately transmitted by the aster leafhopper (Macrosteles quadrilineatus Forbes). Current control practices s...

Journal: :Current Biology 2006
Maria D. Koffa Claudia M. Casanova Rachel Santarella Thomas Köcher Matthias Wilm Iain W. Mattaj

BACKGROUND GTP-loaded Ran induces the assembly of microtubules into aster-like and spindle-like structures in Xenopus egg extract. The microtubule-associated protein (MAP), TPX2, can mediate Ran's role in aster formation, but factors responsible for the transition from aster-like to spindle-like structures have not been described. RESULTS Here we identify a complex that is required for the co...

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