468 research outputs found
The Government of India under Lord Chelmsford, 1916-1921, with special reference to the policies adopted towards constitutional change and political agitation in British India.
This thesis examines the established view of Chelmsford's administration in the light of documentary evidence only recently available. It questions such assumptions as that policy originated in London, that the Government of Inaia were hostile to Chang's, and that Chelmsford was without influence. It is arranged as an analysis of policy, describing Chelmsford's method and its application to politics and reform. The conclusion is that underlying policy there was a coherent idea, formulated in India from the Government's enunciation of the goal of Indian self-government within the Empire. The Government, it is found, had decided they must begin to resolve the contradictions between bureaucracy and Indian advancement, and give positive expression to their acceptance of the goal. Thus, it is shown, the Government worked with collective responsibility in consultation with local governments, legislators and public - as befitted their changing role. They attacked racial discrimination, internal and international, as inappropriate to the Indians' future status. In spite of the dangers of popular activism, they evolved a tactic of non-interference with national politicians, partly because of an admission that Indian aspirations, if not methods, were basically legitimate. They repressed political 'crime' and disorders, but saw them as exceptional and as counterproductive to Indian progress; and, though the repressive habit persisted in the 'Rowlatt' Act, the 1919 atrocities were a local aberration repudiated by Chelmsford. Finally, the Government presided over constitutional reforms in which they tried for the first time to prepare for a future transfer of power. The thesis recognises different influences on policy, limitations to Chelmsford's vision, the obscurity of his personal contribution, and the exceptional unpopularity of his rule. Failures are not disputed, but positive achievements are also presented for scrutiny. It is suggested that they encompassed a fundamental commitment to the future
Coherent Mixing of Singlet and Triplet States in Acrolein and Ketene: A Computational Strategy for Simulating the Electron–Nuclear Dynamics of Intersystem Crossing
We present a theoretical study of intersystem crossing (ISC) in acrolein and ketene with the Ehrenfest method that can describe a superposition of singlet and triplet states. Our simulations illustrate a new mechanistic effect of ISC, namely, that a superposition of singlets and triplets yields nonadiabatic dynamics characteristic of that superposition rather than the constituent state potential energy surfaces. This effect is particularly significant in ketene, where mixing of singlet and triplet states along the approach to a singlet/singlet conical intersection occurs, with the spin–orbit coupling (SOC) remaining small throughout. In both cases, the effects require many recrossings of the singlet/triplet state crossing seam, consistent with the textbook treatment of ISC
How electronic superpositions drive nuclear motion following the creation of a localized hole in the glycine radical cation
In this work we have studied the nuclear and electron dynamics in the glycine cation starting from localized hole states, using the Quantum Ehrenfest (QuEh) method. The nuclear dynamics is controlled both by the initial gradient and by the instantaneous gradient that results from the oscillatory electron dynamics (charge migration). We have used the Fourier transform (FT) of the spin densities to identify the normal modes of the electron dynamics. We observe an isomorphic relationship between the electron dynamics normal modes (ED-NM) and the nuclear dynamics, seen in the vibrational normal modes (Vib-NM). The FT spectra obtained this way show bands that are characteristic of the energy differences between the adiabatic hole states. These bands contain individual peaks that are in one-to-one correspondence with atom pair (+ •) ↔(• +) resonances (APR), which in turn stimulate nuclear motion involving the atom pair. With such understanding we anticipate 'designer' coherent superpositions that can drive nuclear motion in a particular direction
Ecological Drivers of Song Evolution in Birds: Disentangling the Effects of Habitat and Morphology
Environmental differences influence the evolutionary divergence of mating signals through selection acting either directly on signal transmission (“sensory drive”) or because morphological adaptation to different foraging niches causes divergence in “magic traits” associated with signal production, thus indirectly driving signal evolution. Sensory drive and magic traits both contribute to variation in signal structure, yet we have limited understanding of the relative role of these direct and indirect processes during signal evolution. Using phylogenetic analyses across 276 species of ovenbirds (Aves: Furnariidae), we compared the extent to which song evolution was related to the direct influence of habitat characteristics and the indirect effect of body size and beak size, two potential magic traits in birds. We find that indirect ecological selection, via diversification in putative magic traits, explains variation in temporal, spectral, and performance features of song. Body size influences song frequency, whereas beak size limits temporal and performance components of song. In comparison, direct ecological selection has weaker and more limited effects on song structure. Our results illustrate the importance of considering multiple deterministic processes in the evolution of mating signals
Using quantum dynamics simulations to follow the competition between charge migration and charge transfer in polyatomic molecules
Recent work, particularly by Cederbaum and co-workers, has identified the phenomenon of charge migration, whereby charge flow occurs over a static molecular framework after the creation of an electronic wavepacket. In a real molecule, this charge migration competes with charge transfer, whereby the nuclear motion also results in the re-distribution of charge. To study this competition, quantum dynamics simulations need to be performed. To break the exponential scaling of standard grid-based algorithms, approximate methods need to be developed that are efficient yet able to follow the coupled electronic-nuclear motion of these systems. Using a simple model Hamiltonian based on the ionisation of the allene molecule, the performance of different methods based on Gaussian Wavepackets is demonstrated
Lineage diversification and morphological evolution in a large-scale continental radiation: The neotropical ovenbirds and woodcreepers (aves: furnariidae)
Patterns of diversification in species-rich clades provide insight into the processes that generate biological diversity. We tested different models of lineage and phenotypic diversification in an exceptional continental radiation, the ovenbird family Furnariidae, using the most complete species-level phylogenetic hypothesis produced to date for a major avian clade (97% of 293 species). We found that the Furnariidae exhibit nearly constant rates of lineage accumulation but show evidence of constrained morphological evolution. This pattern of sustained high rates of speciation despite limitations on phenotypic evolution contrasts with the results of most previous studies of evolutionary radiations, which have found a pattern of decelerating diversity-dependent lineage accumulation coupled with decelerating or constrained phenotypic evolution. Our results suggest that lineage accumulation in tropical continental radiations may not be as limited by ecological opportunities as in temperate or island radiations. More studies examining patterns of both lineage and phenotypic diversification are needed to understand the often complex tempo and mode of evolutionary radiations on continents. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution
Assembling places and persons: a tenth-century Viking boat burial from Swordle Bay on the Ardnamurchan peninsula, western Scotland
A rare, intact Viking boat burial in western Scotland contained a rich assemblage of grave goods, providing clues to the identity and origins of both the interred individual and the people who gathered to create the site. The burial evokes the mundane and the exotic, past and present, as well as local, national and international identities. Isotopic analysis of the teeth hints at a possible Scandinavian origin for the deceased, while Scottish, Irish and Scandinavian connections are attested by the grave goods. Weapons indicate a warrior of high status; other objects imply connections to daily life, cooking and work, farming and food production. The burial site is itself rich in symbolic associations, being close to a Neolithic burial cairn, the stones of which may have been incorporated into the grave
Systematics, biogeography, and diversification of Scytalopus tapaculos (Rhinocryptidae), an enigmatic radiation of Neotropical montane birds
Copyright © American Ornithological Society 2020. All rights reserved. For permissions, e-mail: [email protected]. We studied the phylogeny, biogeography, and diversification of suboscine passerines in the genus Scytalopus (Rhinocryptidae), a widespread, species-rich, and taxonomically challenging group of Neotropical birds. We analyzed nuclear (exons, regions flanking ultraconserved elements) and mitochondrial (ND2) DNA sequence data for a taxonomically and geographically comprehensive sample of specimens collected from Costa Rica to Patagonia and Brazil. We found that Scytalopus is a monophyletic group sister to Eugralla and consists of 3 main clades roughly distributed in (1) the Southern Andes, (2) eastern Brazil, and (3) the Tropical Andes and Central America. The clades from the Southern Andes and eastern Brazil are sister to each other. Despite their confusing uniformity in plumage coloration, body shape, and overall appearance, rates of species accumulation through time in Scytalopus since the origin of the clade in the Late Miocene are unusually high compared with those of other birds, suggesting rapid non-adaptive diversification in the group. We attribute this to their limited dispersal abilities making them speciation-prone and their occurrence in a complex landscape with numerous barriers promoting allopatric differentiation. Divergence times among species and downturns in species accumulation rates in recent times suggest that most speciation events in Scytalopus predate climatic oscillations of the Pleistocene. Our analyses identified various cases of strong genetic structure within species and lack of monophyly of taxa, flagging populations which likely merit additional study to clarify their taxonomic status. In particular, detailed analyses of species limits are due in S. parvirostris, S. latrans, S. speluncae, the S. atratus complex, and the Southern Andes clade
Remotely-Sensing Chemical Diversity and Function of Native Plants Across Sagebrush-Steppe Landscapes
Plant chemical diversity provides ecosystem services by supporting wildlife diversity and offering sources for novel medicines. Current mapping of phytochemicals can be expensive, time-intensive and provides only a snapshot of available diversity. To overcome this, I will use handheld and airborne instruments collecting near infrared spectra and hyperspectral imagery to remotely sense chemical diversity within plants and ecosystems. I hypothesize that greater plant chemical diversity will be correlated with greater habitat use by wildlife and greater bioactivity of plant extracts. This research provides a powerful tool to map chemical diversity, target wildlife conservation and direct the discovery of novel medicines
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