327 research outputs found
Thermal variability induces sex-specific morphometric changes in zebrafish (Danio rerio)
In nature, organisms are exposed to variable environmental conditions that impact their performance and fitness. Despite the ubiquity of environmental variability, substantial knowledge gaps in our understanding of organismal responses to nonconstant thermal regimes remain. In the present study, using zebrafish (Danio rerio) as a model organism, we applied geometric morphometric methods to examine how challenging but ecologically realistic diel thermal fluctuations experienced during different life stages influence adult body shape, size, and condition. Zebrafish were exposed to either thermal fluctuations (22–32°C) or a static optimal temperature (27°C) sharing the same thermal mean during an early period spanning embryonic and larval ontogeny (days 0–30), a later period spanning juvenile and adult ontogeny (days 31–210), or a combination of both. We found that body shape, size, and condition were affected by thermal variability, but these plasticity-mediated changes were dependent on the timing of ontogenetic exposure. Notably, after experiencing fluctuating temperatures during early ontogeny, females displayed a deeper abdomen while males displayed an elongated caudal peduncle region. Moreover, males displayed beneficial acclimation of body condition under lifelong fluctuating temperature exposure, whereas females did not. The present study, using ecologically realistic thermal regimes, provides insight into the timing of environmental experiences that generate phenotypic variation in zebrafish.publishedVersio
Electrical transport studies of quench condensed Bi films at the initial stage of film growth: Structural transition and the possible formation of electron droplets
The electrical transport properties of amorphous Bi films prepared by
sequential quench deposition have been studied in situ. A
superconductor-insulator (S-I) transition was observed as the film was made
increasingly thicker, consistent with previous studies. Unexpected behavior was
found at the initial stage of film growth, a regime not explored in detail
prior to the present work. As the temperature was lowered, a positive
temperature coefficient of resistance (dR/dT > 0) emerged, with the resistance
reaching a minimum before the dR/dT became negative again. This behavior was
accompanied by a non-linear and asymmetric I-V characteristic. As the film
became thicker, conventional variable-range hopping (VRH) was recovered. We
attribute the observed crossover in the electrical transport properties to an
amorphous to granular structural transition. The positive dR/dT found in the
amorphous phase of Bi formed at the initial stage of film growth was
qualitatively explained by the formation of metallic droplets within the
electron glass.Comment: 7 pages, 6 figure
'To live and die [for] Dixie': Irish civilians and the Confederate States of America
Around 20,000 Irishmen served in the Confederate army in the Civil War. As a result, they left behind, in various Southern towns and cities, large numbers of friends, family, and community leaders. As with native-born Confederates, Irish civilian support was crucial to Irish participation in the Confederate military effort. Also, Irish civilians served in various supporting roles: in factories and hospitals, on railroads and diplomatic missions, and as boosters for the cause. They also, however, suffered in bombardments, sieges, and the blockade. Usually poorer than their native neighbours, they could not afford to become 'refugees' and move away from the centres of conflict. This essay, based on research from manuscript collections, contemporary newspapers, British Consular records, and Federal military records, will examine the role of Irish civilians in the Confederacy, and assess the role this activity had on their integration into Southern communities. It will also look at Irish civilians in the defeat of the Confederacy, particularly when they came under Union occupation. Initial research shows that Irish civilians were not as upset as other whites in the South about Union victory. They welcomed a return to normalcy, and often 'collaborated' with Union authorities. Also, Irish desertion rates in the Confederate army were particularly high, and I will attempt to gauge whether Irish civilians played a role in this. All of the research in this paper will thus be put in the context of the Drew Gilpin Faust/Gary Gallagher debate on the influence of the Confederate homefront on military performance. By studying the Irish civilian experience one can assess how strong the Confederate national experiment was. Was it a nation without a nationalism
Fertility, Living Arrangements, Care and Mobility
There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century – demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed
The New Urban Revival in the United States
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68657/2/10.1080_00420989320081901.pd
Immigration and Internal Migration 'Flight' from US Metropolitan Areas: Toward a New Demographic Balkanisation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68704/2/10.1080_00420989550012861.pd
Astronomical Distance Determination in the Space Age: Secondary Distance Indicators
The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)
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