4,270 research outputs found
Reconstructing Cenozoic vegetation from proxy data and models – A NECLIME synthesis (Editorial)
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<i>Aporosa</i> Blume from the paleoequatorial rainforest of Bikaner, India: Its evolution and diversification in deep time
The Gondwanan origin, northward migration and subsequent collision with Asia means that the Indian subcontinent is of particular interest regarding the origin and dispersal of numerous plants and animal species. With this in mind, we describe a fossil leaf of Aporosa Blume (Phyllanthaceae) from the Paleogene of the Indian subcontinent and discuss its evolution and diversification with respect to the moving Indian plate and its connection with Southeast Asia since the early Cenozoic. At present, Aporosa Blume is confined to Southeast Asia with a few species in India and New Guinea. It is represented by six endemic species growing in the evergreen forests of India and Sri Lanka, including Aporosa acuminata Thwaites, which is morphologically close to the here described fossil from Bikaner, Rajasthan, India. From the age of the fossil and the distribution of its modern comparable form, it is assumed that Aporosa originated on the Indian subcontinent and then was distributed to Southeast Asia, supporting the ‘Out of India’ hypothesis. Diversification of the genus might have taken place either in the Paleogene or Neogene. Our fossil leaf material also indicates the existence of palaeoequatorial (< 10° N) tropical rain forests in western India during the Paleogene in contrast to dry and desertic climate occurring today
Occurrence of <i>Shorea</i> Roxburgh ex C. F. Gaertner (Dipterocarpaceae) in the Neogene Siwalik forests of eastern Himalaya and its biogeography during the Cenozoic of Southeast Asia
We report the occurrence of two leaf impressions and one leaf compression along with one winged fruit and two fruiting calyx lobes, resembling those of Shorea Roxburgh ex C. F. Gaertner, in the lower Siwalik (Dafla Formation, middle to upper Miocene), middle Siwalik (Subansiri Formation, Pliocene) and upper Siwalik (Kimin Formation, upper Pliocene to lower Pleistocene) sediments exposed in Arunachal Pradesh, eastern Himalaya. We determine their taxonomic positions based on morphological comparison with similar extant and fossil specimens and discuss their phytogeographic and paleoclimatic implications in terms of the distribution and habitat of fossil and modern populations. The Miocene winged fruit is recognized as Shorea pinjoliensis Khan, R.A. Spicer et Bera, sp. nov. while the Pliocene and Plio-Pleistocene fruiting calyx lobes are recognized as Shorea bhalukpongensis Khan, R.A. Spicer et Bera, sp. nov. and Shorea chandernagarensis Khan, R.A. Spicer et Bera, sp. nov. respectively. Based on leaf architecture the Miocene, Pliocene and Plio-Pleistocene leaves are recognized as Shorea mioobtusa Khan, R.A. Spicer et Bera, sp. nov., Shorea pliotumbuggaia Khan, R.A. Spicer et Bera, sp. nov. and Shorea nepalensis Konomatsu et Awasthi respectively. The discovery of members of Shorea indicates that they had arrived in a tropical, warm and humid eastern Himalaya by the Mio-Pleistocene. Present and earlier records of Shorea suggest that this genus was a common forest element during Neogene (Miocene time) as well as in the Siwalik forests including Arunachal sub-Himalaya. In this paper, we also review in detail the biogeographic history and suggest possible migration routes of the genus
First occurrence of mastixioid (Cornaceae) fossil in India and its biogeographic implications
Mastixioids in the family Cornaceae, are presently native only in limited areas of Asia, they have rich fossil fruit record in Cenozoic sediments of Europe and North America, but unfortunately none have been reported from Cenozoic sediments of India and Asia until now. Here, we report the occurrence of leaf remains (both impression and compression) along with carbonised fruits, resembling morphologically and anatomically those of the extant endemic species Mastixia arborea C.B. Clarke. Our materials were recovered from the middle Miocene to early Pleistocene Siwalik sediments exposed around West Kameng and Papumpare districts in Arunachal Pradesh, eastern Himalaya. These new fossil materials confirm the existence of Mastixia in the Miocene-Pleistocene Siwalik forests in India. At present the modern analogue does not grow in the eastern Himalaya and is endemic to the tropical evergreen forests of the Western Ghats, situated at the same palaeolatitude as the fossil locality. Extinction from the entire eastern Himalaya and probable movement of this taxon to the Western Ghats is likely due to climate change in the area, related to the Himalayan Orogeny during Miocene–Pleistocene times. The disappearance of Mastixia from this area may be related to the gradual intensification of rainfall seasonality since the late Miocene. The recovery of this species and our earlier-described evergreen taxa from the same Siwalik time (Mio-Pleistocene), suggest the existence of tropical, warm and humid climatic conditions during the period of deposition. The leaf and fruit remains are here described as new species, namely Mastixia asiatica Khan, Bera M et Bera S, sp. nov. and Mastixia siwalika Khan, Bera M et Bera S, sp. nov. respectively. This report documents the first fossil record of Mastixia leaf remains using both macro and micromorphological characters. We also review the historical phytogeography, and highlight the phytogeographic implication of, the mastixioids
Elasto-plastic impact of hemispherical shell impacting on hard rigid sphere
An analysis of plastic stress waves for cylindrical metallic projectile in impact is extended to an analysis of a hemispherical shell suffereing plastic deformation during the process of impact. It is assumed that the hemispherical shell with a prescribed launch velocity impinges a fixed rigid sphere of diameter equal to the internal diameter of the shell. The dynamic biaxial state of stress present in the shell during deformation is investigated. The analysis is valuable for studying the state of stress during large plastic deformation of a hemispherical shell
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Guilty Lives: The Failed Search for Authenticity in Contemporary Society
This paper argues that guilt is central to the contemporary fixation with personal authenticity. Building on Basterra’s (2004) analysis of guilt and the tragic form, I argue the search for authenticity represents an act of agency, a struggle against external social determination. This struggle is embodied in a whole series of minor ‘authenticity rituals’ that we become passionately attached to. These rituals provoke compulsive self-monitoring within the subject. Instead of freeing ourselves from control, the search for authenticity actually deepens it in unexpected ways
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Shooting the shit: The role of bullshit in organisations
This article argues that a great deal of both 'talk' and 'text' in organisational settings is, ultimately, bullshit. By 'bullshit' I mean the type of organisational speech and text that is produced with scant regard for the truth and is used to willfully mislead and to pursue the interests of the bullshitter. Bullshit is particularly prevalent in immaterial roles that lack a clear sense of social purpose. In these contexts, employees try to occupy themselves by engaging in bullshit. They do this by circulating discourses which are strategically ambiguous, over-packed with information and deliberately fleeting in nature. In order to construct these discourses, they frequently turn to examples set by the management fashion industry. When bullshit begins to take hold of an organisation, it can have surprisingly positive effects. It can create a positive image for the company and can help to increase self-confidence and build legitimacy. However, this often comes with some distinctly darker consequences: primary tasks are crowded out, valued occupational identities are compromised and stakeholder trust is undermined. Ultimately, bullshit leaves us with organisations that may be appealing on the surface but are distinctly brittle
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Extutions: The Other Side of Institutions
Institutions are structured around an extitutional core that always escapes them. Extitutions are figures which have an ambiguous, destabilised and sometimes threatening quality. The central problem that institutional workers face is dealing with and ultimately capturing these extitutions. I look at two ways that institutions have sought to deal with extitutions – through attempts to discipline them or through more recent attempts to control them. I suggest that the generalised crisis of institutions may involve this passage from disciplining extitutions to controlling them
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