Conclusion

2019 ◽  
pp. 187-200
Author(s):  
Brent M. S. Campney

The conclusion synthesizes the book’s themes. Substantively, it summarizes racist violence and its temporal and spatial adaptations, exclusion and the growth of sundown towns, Jim Crow restrictions and their expansion, and police and their appropriation of mob violence. It reviews the black response through armed resistance, legal, journalistic, and organizational challenges, and concentration of population in cities. It assesses the role of modernity in facilitating these changes. In terms of methodology, the conclusion highlights a more nuanced assessment of targeted violence against black families. In historiographic terms, it suggests that the fear of interracial sex in the Midwest pre-dated that in the South, that the concentration of blacks motivated more racist violence than did the origin of the white settlers, and that situational suicides by blacks faced with imminent death require more critical interrogation.

2010 ◽  
Vol 27 (1-2) ◽  
pp. 81-90
Author(s):  
Krishna Poudel

Mountains have distinct geography and are dynamic in nature compared to the plains. 'Verticality' and 'variation' are two fundamental specificities of the mountain geography. They possess distinct temporal and spatial characteristics in a unique socio-cultural setting. There is an ever increasing need for spatial and temporal data for planning and management activities; and Geo Information (GI) Science (including Geographic Information and Earth Observation Systems). This is being recognized more and more as a common platform for integrating spatial data with social, economic and environmental data and information from different sources. This paper investigates the applicability and challenges of GISscience in the context of mountain geography with ample evidences and observations from the mountain specific publications, empirical research findings and reports. The contextual explanation of mountain geography, mountain specific problems, scientific concerns about the mountain geography, advances in GIScience, the role of GIScience for sustainable development, challenges on application of GIScience in the contexts of mountains are the points of discussion. Finally, conclusion has been made with some specific action oriented recommendations.


Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1497-1505 ◽  
Author(s):  
A.H. Wikramanayake ◽  
B.P. Brandhorst ◽  
W.H. Klein

During early embryogenesis, the highly regulative sea urchin embryo relies extensively on cell-cell interactions for cellular specification. Here, the role of cellular interactions in the temporal and spatial expression of markers for oral and aboral ectoderm in Strongylocentrotus purpuratus and Lytechinus pictus was investigated. When pairs of mesomeres or animal caps, which are fated to give rise to ectoderm, were isolated and cultured they developed into ciliated embryoids that were morphologically polarized. In animal explants from S. purpuratus, the aboral ectoderm-specific Spec1 gene was activated at the same time as in control embryos and at relatively high levels. The Spec1 protein was restricted to the squamous epithelial cells in the embryoids suggesting that an oral-aboral axis formed and aboral ectoderm differentiation occurred correctly. However, the Ecto V protein, a marker for oral ectoderm differentiation, was detected throughout the embryoid and no stomodeum or ciliary band formed. These results indicated that animal explants from S. purpuratus were autonomous in their ability to form an oral-aboral axis and to differentiate aboral ectoderm, but other aspects of ectoderm differentiation require interaction with vegetal blastomeres. In contrast to S. purpuratus, aboral ectoderm-specific genes were not expressed in animal explants from L. pictus even though the resulting embryoids were morphologically very similar to those of S. purpuratus. Recombination of the explants with vegetal blastomeres or exposure to the vegetalizing agent LiCl restored activity of aboral ectoderm-specific genes, suggesting the requirement of a vegetal induction for differentiation of aboral ectoderm cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Archaea ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Elisabeth W. Vissers ◽  
Flavio S. Anselmetti ◽  
Paul L. E. Bodelier ◽  
Gerard Muyzer ◽  
Christa Schleper ◽  
...  

Despite their crucial role in the nitrogen cycle, freshwater ecosystems are relatively rarely studied for active ammonia oxidizers (AO). This study of Lake Lucerne determined the abundance of bothamoAgenes and gene transcripts of ammonia-oxidizing archaea (AOA) and bacteria (AOB) over a period of 16 months, shedding more light on the role of both AO in a deep, alpine lake environment. At the surface, at 42 m water depth, and in the water layer immediately above the sediment, AOA generally outnumbered AOB. However, in the surface water during summer stratification, when both AO were low in abundance, AOB were more numerous than AOA. Temporal distribution patterns of AOA and AOB were comparable. Higher abundances ofamoAgene transcripts were observed at the onset and end of summer stratification. In summer, archaealamoAgenes and transcripts correlated negatively with temperature and conductivity. Concentrations of ammonium and oxygen did not vary enough to explain theamoAgene and transcript dynamics. The observed herbivorous zooplankton may have caused a hidden flux of mineralized ammonium and a change in abundance of genes and transcripts. At the surface, AO might have been repressed during summer stratification due to nutrient limitation caused by active phytoplankton.


2021 ◽  
Vol 9 ◽  
Author(s):  
Kyle D. Kittelberger ◽  
Solomon V. Hendrix ◽  
Çağan Hakkı Şekercioğlu

Due to the increasing popularity of websites specializing in nature documentation, there has been a surge in the number of people enthusiastic about observing and documenting nature over the past 2 decades. These citizen scientists are recording biodiversity on unprecedented temporal and spatial scales, rendering data of tremendous value to the scientific community. In this study, we investigate the role of citizen science in increasing knowledge of global biodiversity through the examination of notable contributions to the understanding of the insect suborder Auchenorrhyncha, also known as true hoppers, in North America. We have compiled a comprehensive summary of citizen science contributions—published and unpublished—to the understanding of hopper diversity, finding over fifty previously unpublished country and state records as well as dozens of undescribed and potentially undescribed species. We compare citizen science contributions to those published in the literature as well as specimen records in collections in the United States and Canada, illuminating the fact that the copious data afforded by citizen science contributions are underutilized. We also introduce the website Hoppers of North Carolina, a revolutionary new benchmark for tracking hopper diversity, disseminating knowledge from the literature, and incorporating citizen science. Finally, we provide a series of recommendations for both the entomological community and citizen science platforms on how best to approach, utilize, and increase the quality of sightings from the general public.


2021 ◽  
Author(s):  
Qianqian Zhang ◽  
E Lizhu ◽  
Weixing Dai ◽  
Mingliang Xu ◽  
Jianrong Ye

AbstractPlant growth and development face constant threat from various environmental stresses. Transcription factors (TFs) are crucial for maintaining balance between plant growth and defense. Trihelix TFs display multifaceted functions in plant growth, development, and responses to various biotic and abiotic stresses. Here, we explore the role of a trihelix TF, ZmGT-3b, in regulating the growth–defense tradeoff in maize (Zea mays). ZmGT-3b is primed for instant response to Fusarium graminearum challenge by implementing a rapid and significant reduction of its expression to suppress seedling growth and enhance disease resistance. ZmGT-3b knockdown led to diminished growth, but improved disease resistance and drought tolerance in maize seedlings. In ZmGT-3b knockdown seedlings, the chlorophyll content and net photosynthetic rate were strongly reduced, whereas the contents of major cell wall components, such as lignin, were synchronically increased. Correspondingly, ZmGT-3b knockdown specifically downregulated photosynthesis-related genes, especially ZmHY5 (encoding a conserved central regulator of seedling development and light responses), but synchronically upregulated genes associated with secondary metabolite biosynthesis and defense-related functions. ZmGT-3b knockdown induced defense-related transcriptional reprogramming and increased biosynthesis of lignin without immune activation. These data suggest that ZmGT-3b is a regulator of plant growth–defense tradeoff that coordinates metabolism during growth-to-defense transitions by optimizing the temporal and spatial expression of photosynthesis- and defense-related genes.One-sentence summaryZmGT-3b regulates photosynthesis activity and synchronically suppresses defense response.


2012 ◽  
Vol 573-574 ◽  
pp. 213-217
Author(s):  
Gui Lan Zhang

Purification effects of riparian wetland in a natural state on pollutants are unstable and are always influenced by hydrology, climate, and extent of wetlands development. For this reason, study of the role of the purification function of riparian wetland in a natural state is ongoing. In this study, with the Kouma section of the Yellow River wetlands as the study area, using the field experiment method and the 15N enriched technique, the agricultural non-point nitrogen pollution control function of Phragmites communis Trin in riparian wetlands was studied. Artificial runoff events enabled the collection of a temporal and spatial array of samples within the wetland so that the plume of runoff water moving through the wetland could be traced and its attenuation determined.


1973 ◽  
Vol 3 (1) ◽  
pp. 6-11
Author(s):  
Clement Tsehloane Keto

People of African descent in America occupy a singular position in relation to the race problems faced by Blacks in South Africa. Many Afro-Americans have had firsthand experience with the practice of race discrimination either in its blatant Jim Crow manifestations or in its more covert institutional forms. This common experience with race discrimination in South Africa and the United States makes it possible, for example, to correlate W.E.B. Dubois' description of the warring “double consciousness” of the black American made in 1903 with the expressions of frustration written by Albert Luthuli in 1962. This commonality also establishes a basis from which a meaningful assessment can be made regarding the historical role of black Americans in the race issue of South Africa.


2020 ◽  
Vol ahead-of-print (0) ◽  
pp. 1-21
Author(s):  
Madeleine Kirstein ◽  
Mathias Schaefer ◽  
Tanja Schnittfinke ◽  
Stefan Greiving ◽  
Rouven Küsters

In order to reveal the present and future flooding impacts on residential and mixed-use areas, a parallel modelling approach (PMA) was carried out. With the use of geo-information systems (GIS), temporal and spatial impacts can be quantified and visualised, while the results of the proposed method justify adequate regional planning strategies for the Ruhr, Germany. As an information system which is regularly updated within a cooperation process between the municipalities concerned, the so called ruhrFISְ of the Ruhr Regional Association (RVR) seems to be a promising approach to improve the evidence basis for adaptation actions.


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