Gametophytic development and fertilization in Macrocystis integrifolia

1968 ◽  
Vol 46 (6) ◽  
pp. 777-782 ◽  
Author(s):  
Kathleen Cole
Keyword(s):  
Cytological Investigation ◽  
Nuclear Activity ◽  
Male Nucleus ◽  
Sperm Penetration ◽  
Macrocystis Integrifolia ◽  
Developmental Characteristics ◽  
Nuclear Cytology ◽  
Peripheral Cytoplasm

A cytological investigation of gametophytic development and fertilization was conducted on cultured gametophytes of Macrocystis integrifolia. Most developmental characteristics are similar to those previously reported for other members of the order Laminariales, although some modifications were noted in the production of antheridia and spermatozoids. One of the most significant contributions of this study concerned the nuclear cytology of the egg during fertilization. There appear to be two fertilization phases: sperm penetration and nuclear activity within the egg. After penetration of the egg by one spermatozoid, the male nucleus remains in the peripheral cytoplasm while the egg nucleus undergoes mitosis, producing two daughter nuclei, one of which degenerates. The male nucleus then enters prophase and migrates to the remaining female nucleus, which is also in prophase. Karyogamy occurs while both nuclei are in prophase.

Qualitative study on “hydropic degeneration” of The hepatocytes in viral hepatitis

1990 ◽  
Vol 48 (3) ◽  
pp. 568-569
Author(s):  
Le Meizhao ◽  
Ye Ming ◽  
Song Xiaoming ◽  
Xu Jiazhang
Keyword(s):  
Qualitative Study ◽  
Viral Hepatitis ◽  
Chronic Active Hepatitis ◽  
Microscopic Observation ◽  
Hydropic Degeneration ◽  
Light Microscopic Observation ◽  
Biopsy Specimens ◽  
Endoplasm Reticulum ◽  
Mixed Fluid ◽  
Peripheral Cytoplasm

“Hydropic degeneration” of the hepatocytes are often found in biopsy of the liver of some kinds of viral hepatitis. Light microscopic observation, compareted with the normal hepatocytes, they are enlarged, sometimes to a marked degree when the term “balloning” degeneration is used. Their cytoplasm rarefied, and show some clearness in the peripheral cytoplasm, so, it causes a hydropic appearance, the cytoplasm around the nuclei is granulated. Up to the present, many studies belive that main ultrastructural chenges of hydropic degeneration of the hepatocytes are results of the RER cristae dilatation with degranulation and disappearance of glycogen granules.The specimens of this study are fixed with the mixed fluid of the osmium acidpotassium of ferricyanide, Epon-812 embed. We have observed 21 cases of biopsy specimens with chronic severe hepatitis and severe chronic active hepatitis, and found that the clear fields in the cytoplasm actually are a accumulating place of massive glycogen. The granules around the nuclei are converging mitochondria, endoplasm reticulum and other organelles.

Developmental characteristics of visual cognitive function during childhood according to exploratory eye movements

2009 ◽  
Vol 31 (10) ◽  
pp. 750-757 ◽  
Author(s):  
Chiyomi Egami ◽  
Kiichiro Morita ◽  
Takashi Ohya ◽  
Youhei Ishii ◽  
Yushiro Yamashita ◽  
...  
Keyword(s):  
Eye Movements ◽  
Cognitive Function ◽  
Developmental Characteristics ◽  
Visual Cognitive

THE NUCLEAR ACTIVITY OF LESIONS OF THE CERVIX

1969 ◽  
Vol 2 (13) ◽  
pp. 635-639
Author(s):  
G. Thoms ◽  
E. J. Groot
Keyword(s):  
Nuclear Activity

Testing the link between mergers and AGN in the Arp 245 system

2020 ◽  
Vol 15 (S359) ◽  
pp. 192-194
Author(s):  
Elismar Lösch ◽  
Daniel Ruschel-Dutra
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Spherical Surface ◽  
Galaxy Mergers ◽  
Nuclear Activity ◽  
Upper Limit ◽  
Spherical Surfaces ◽  
Galactic Centers ◽  
Merger Event ◽  
Major Merger

AbstractGalaxy mergers are known to drive an inflow of gas towards galactic centers, potentia- lly leading to both star formation and nuclear activity. In this work we aim to study how a major merger event in the ARP 245 system is linked with the triggering of an active galactic nucleus (AGN) in the NGC galaxy 2992. We employed three galaxy collision numerical simulations and calculated the inflow of gas through four different concentric spherical surfaces around the galactic centers, estimating an upper limit for the luminosity of an AGN being fed the amount of gas crossing the innermost spherical surface. We found that these simulations predict reasonable gas inflow rates when compared with the observed AGN luminosity in NGC 2992.

Inspirational Teachers’ Model: A Constructivist Grounded Theory Study in Gifted Education

2021 ◽  
pp. 016235322110235
Author(s):  
Claudia A. Cornejo-Araya ◽  
Leonie Kronborg
Keyword(s):  
Grounded Theory ◽  
Constructivist Grounded Theory ◽  
Future Research ◽  
Theory Approach ◽  
Positive Attitudes ◽  
Safe Learning Environment ◽  
Contextual Determinants ◽  
Developmental Characteristics ◽  
Highly Able ◽  
Grounded Theory Approach

Adopting a constructivist grounded theory approach, 91 students from Years 9 to 11, in gifted educational programs from three schools in Melbourne, nominated their inspiring teachers. Eleven teachers, who received the highest number of nominations, were invited to an interview and an observation of their teaching. The emerged theoretical construct was identified as “Opening new possibilities: Inspiring teachers of gifted and highly able students,” which is further explained through three main categories: Being a knowledgeable and passionate teacher, creating an academically safe learning environment, and teaching beyond and above the regular curriculum. In addition, the theoretical process was explained through three phases: Expanding knowledge and understanding, Fostering positive attitudes, and Encouraging students to take action. Contextual determinants were considered to analyze and report the findings: students’ developmental characteristics, school culture, curriculum, and gifted educational provisions. Findings are discussed in the light of existing literature, as well as study limitations and ideas for future research.

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