Regulation of development in the fully grown mouse oocyte: chromosome-mediated temporal and spatial differentiation of the cytoplasm and plasma membrane

Development ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 213-238
Author(s):  
Jonathan Van Blerkom ◽  
Hobart Bell

The relationship between nuclear maturation and the differentiation of the cytoplasm and plasma membrane during resumption of arrested meiosis was investigated by culture of GV- and MII-stagemouse oocytes in the presence and absence of nocodazole. Culture in the presence of nocodazole was associated with dispersal of MI and MII chromosomes throughout the subplasmalemmal cytoplasm. A progression of cortical (thickening of actin filaments) and plasma membrane changes (denudation of microvilli, reduction in cell surface glycoproteins, formation of chromosome-containing evaginations) that normally occurs in proximity to chromosomes associated with intact MI or MII spindles tookplace only in those regions of the cortical cytoplasm containing the dispersed subplasmalemmal chromosomes. The dispersion and migration of the chromosomes occurred in an apparently random fashion. Fluorescent probe analysis of normal and treated oocytes indicated a stage-specific association between the spatial distribution of chromosomes and mitochondria. Transfer of individual bivalent chromosomes to untreated oocytes at different stages of maturation and to cytoplasts derived from oocytes anucleated prior to GVB demonstrated (1) the necessity of chromosomes for cytoplasmic and plasma membrane differentiation, and (2) that the capacity of the cytoplasm and plasma membrane to differentiate in response to the presence of a chromosome is acquired prior to GVB.

1990 ◽  
Vol 33 (3) ◽  
pp. 476-487 ◽  
Author(s):  
Dale Evan Metz ◽  
Vincent J. Samar ◽  
Nicholas Schiavetti ◽  
Ronald W. Sitler

Regression and principal components analyses were employed to study the relationship between 28 segmental and suprasegmental acoustic parameters of speech production and measures of speech intelligibility for 40 severely to profoundly hearing-impaired persons in an effort to extend the findings of Metz, Samar, Schiavetti, Sitler, and Whitehead (1985). The principal components analysis derived six factors that accounted for 59% of the variance in the original 28 parameters. Consistent with the findings of Metz et al., a subsequent regression analysis using these six factors as predictor variables revealed two factors with strong predictive relationships to speech intelligibility. One factor primarily reflected segmental production processes related to the temporal and spatial differentiation of phonemes, whereas the other primarily reflected suprasegmental production processes associated with contrastive stress. However, the predictive capability of the present factor structure was somewhat reduced relative to the findings of Metz et al. (1985). Data presented indicate that the populations sampled in the two studies may have differed on one or more dimensions of subject characteristics. Considered collectively, the present findings and the findings of Metz et al. support the tractability of employing selected acoustic variables for the estimation of speech intelligibility.


2018 ◽  
Vol 15 (3) ◽  
pp. 389-398
Author(s):  
Ruchi Singh

Rural economies in developing countries are often characterized by credit constraints. Although few attempts have been made to understand the trends and patterns of male out-migration from Uttar Pradesh (UP), there is dearth of literature on the linkage between credit accessibility and male migration in rural Uttar Pradesh. The present study tries to fill this gap. The objective of this study is to assess the role of credit accessibility in determining rural male migration. A primary survey of 370 households was conducted in six villages of Jaunpur district in Uttar Pradesh. Simple statistical tools and a binary logistic regression model were used for analyzing the data. The result of the empirical analysis shows that various sources of credit and accessibility to them play a very important role in male migration in rural Uttar Pradesh. The study also found that the relationship between credit constraints and migration varies across various social groups in UP.


2012 ◽  
Vol 5 (1) ◽  
pp. 39-49
Author(s):  
Tzu-Hui Chen

This narrative aims to explore the meaning and lived experiences of marriage that a unique immigrant population—“foreign brides” in Taiwan—possesses. This convergence narrative illustrates the dynamics and complexity of mail-order marriage and women's perseverance in a cross-cultural context. The relationship between marriage, race, and migration is analyzed. This narrative is comprised of and intertwined by two story lines. One is the story of two “foreign brides” in Taiwan. The other is my story about my cross-cultural relationship. All the dialogues are generated by 25 interviews of “foreign brides” in Taiwan and my personal experience.


The environment has always been a central concept for archaeologists and, although it has been conceived in many ways, its role in archaeological explanation has fluctuated from a mere backdrop to human action, to a primary factor in the understanding of society and social change. Archaeology also has a unique position as its base of interest places it temporally between geological and ethnographic timescales, spatially between global and local dimensions, and epistemologically between empirical studies of environmental change and more heuristic studies of cultural practice. Drawing on data from across the globe at a variety of temporal and spatial scales, this volume resituates the way in which archaeologists use and apply the concept of the environment. Each chapter critically explores the potential for archaeological data and practice to contribute to modern environmental issues, including problems of climate change and environmental degradation. Overall the volume covers four basic themes: archaeological approaches to the way in which both scientists and locals conceive of the relationship between humans and their environment, applied environmental archaeology, the archaeology of disaster, and new interdisciplinary directions.The volume will be of interest to students and established archaeologists, as well as practitioners from a range of applied disciplines.


Information ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 153
Author(s):  
Penglong Li ◽  
Zuoqin Shi ◽  
Yi Ding ◽  
Ling Zhao ◽  
Zezhong Ma ◽  
...  

Museum cultural relics represent a special material cultural heritage, and modern interpretations of them are needed in current society. Based on the catalogue data of cultural relics published by the State Administration of Cultural Heritage, this paper analyzes the continuity and intermittentness of cultural relics in time series by using the method of continuity judgment of cultural relics, analyzes the aggregation and migration of cultural relics in space by using the method of spatial analysis, and then uses cosine similarity to explain the similarity distribution in space and time. The results show that the overall distribution of cultural relics exhibits the characteristics of class aggregation, dynasty aggregation and regional aggregation. From the perspective of a time scale, cultural relics have different “life cycles”, displaying continuity, intermittentness, and similarity. From the perspective of a spatial scale, the cultural relic distribution forms a small “cultural communication circle”, showing aggregation, migration, and similarity. The temporal and spatial distribution of cultural relics exhibited more similar characteristics among dynasties that were closer together than those that were far away.


Author(s):  
Sarah Gaby

The “legacy effect” of lynchings and other forms of racialized violence has shaped patterns of inequality in America. While past studies have been relatively similar in their design—relating basic counts of lynchings to various contemporary outcomes—I argue for and demonstrate a more nuanced approach. I show that if we think of racialized violence as more than just the act of lynching, and consider both the temporal and spatial proximity between historic events of racial violence and contemporary inequality, we can establish this relationship in a more fulsome way. In the case of this study, the relationship is drawn to housing segregation. I argue that expanding the conceptualization of racial violence is critical for both empirical inquiry and shaping community efforts around redress.


2001 ◽  
Vol 197 (6) ◽  
pp. 441-447 ◽  
Author(s):  
Seiji Shibuya ◽  
Yoshihiro Wakayama ◽  
Makoto Murahashi ◽  
Hiroko Kojima ◽  
Hiroaki Oniki ◽  
...  

1998 ◽  
Vol 55 (S1) ◽  
pp. 9-21 ◽  
Author(s):  
Carol L Folt ◽  
Keith H Nislow ◽  
Mary E Power

The Atlantic salmon (Salmo salar) is a model species for studying scale issues (i.e., the extent, duration, and resolution of a study or natural process) in ecology. Major shifts in behavior and habitat use over ontogeny, along with a relatively long life span and large dispersal and migration distances, make scale issues critical for effective conservation, management, and restoration of this species. The scale over which a process occurs must be linked to the research design and we illustrate this with a discussion of resource tracking by Atlantic salmon. Identifying scale inconsistencies (e.g., when a process is evident at one scale but not another) is shown to be an effective means by which some scale-dependent processes are understood. We review the literature to assess the temporal and spatial scales used in Atlantic salmon research and find most current studies appear to sacrifice spatial and temporal extent for increased resolution. Finally, we discuss research strategies for expanding the temporal and spatial scales in salmon research, such as conducting multiple scales studies to elucidate scale inconsistencies, identifying mechanisms, and using techniques and approaches to generalize across studies and over time and space.


2008 ◽  
Vol 47 (1) ◽  
pp. 71-97 ◽  
Author(s):  
Lygia Sigaud

The article examines a 30-year experience of collective ethnography in the sugarcane plantations of Brazil's Northeast. Over this period, the research group has worked in different temporal and spatial contexts, continually exchanging its findings. The author draws on her experience as part of the research group in order to focus on the conditions of entering the field, the seasonal variations and geographic displacements, the research group's morphology and the overall implications for anthropological knowledge. Debates over ethnography have neglected the relationship between the social conditions in which anthropologists carry out their work and what they are able to write about the social world. This article sets out to fill this gap.


1998 ◽  
Vol 55 (7) ◽  
pp. 1573-1582 ◽  
Author(s):  
Shelley E Arnott ◽  
John J Magnuson ◽  
Norman D Yan

Richness estimates are dependent on the spatial and temporal extent of the sampling programme and the method used to predict richness. We assessed crustacean zooplankton richness in eight Canadian Shield lakes at different temporal and spatial scales using three methods of estimation: cumulative, asymptotic, and Chao's index. Percent species detected increased with the number of spatial, intraannual, or interannual samples taken. Single samples detected 50% of the annual species pool and 33% of the total estimated species pool. This suggests that previous estimates of zooplankton richness, based on single samples in individual lakes, are too low. Our richness estimates for individual lakes approach the total number of zooplankton found in some regions of Canada, suggesting that each lake has most taxa at some time, the majority being very rare. Single-year richness estimates provided poor predictions of multiple-year richness. The relationship between richness and environmental variables was dependent on the method of estimation and the number of samples used. We conclude that richness should be treated as an "index" rather than an absolute and sampling efforts should be standardized. We recommend an asymptotic approach to estimate zooplankton richness because the number of samples taken influenced it less.


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