History of Value-at-Risk: 1922-1998

value-at-risk history

An introduction to Elinor Glyn : her life and legacy

This special issue of Women: A Cultural Review re-evaluates an author who was once a household name, beloved by readers of romance, and whose films were distributed widely in Europe and the Americas. Elinor Glyn (1864–1943) was a British author of romantic fiction who went to Hollywood and became famous for her movies. She was a celebrity figure of the 1920s, and wrote constantly in Hearst's press. She wrote racy stories which were turned into films—most famously, Three Weeks (1924) and It (1927). These were viewed by the judiciary as scandalous, but by others—Hollywood and the Spanish Catholic Church—as acceptably conservative. Glyn has become a peripheral figure in histories of this period, marginalized in accounts of the youth-centred ‘flapper era’. Decades on, the idea of the ‘It Girl’ continues to have great pertinence in the post-feminist discourses of the twenty-first century. The 1910s and 1920s saw the development of intermodal networks between print, sound and screen cultures. This introduction to Glyn's life and legacy reviews the cross-disciplinary debate sparked by renewed interest in Glyn by film scholars and literary and feminist historians, and offers a range of views of Glyn's cultural and historical significance and areas for future research

Deception in context: coding nonverbal cues, situational variables and risk of detection

There are many situations in which deception may arise and understanding the behaviors associated with it are compounded by various contexts in which it may occur. This paper sets out a coding protocol for identifying cues to deception and reports on three studies, in which deception was studied in different contexts. The contexts involved manipulating risks (i.e., probability) of being detected and reconnaissance, both of which are related to terrorist activities. Two of the studies examined the impact of changing the risks of deception detection, whilst the third investigated increased cognitive demand of duplex deception tasks including reconnaissance and deception. In all three studies, cues to deception were analyzed in relation to observable body movements and subjective impressions given by participants. In general, the results indicate a pattern of hand movement reduction by deceivers, and suggest the notion that raising the risk of detection influences deceivers? behaviors. Participants in the higher risk condition displayed increased negative affect (found in deceivers) and tension (found in both deceivers and truth-tellers) than those in lower risk conditions

Root anatomical traits contribute to deeper rooting of maize under compacted field conditions

© The Author(s) 2020. To better understand the role of root anatomy in regulating plant adaptation to soil mechanical impedance, 12 maize lines were evaluated in two soils with and without compaction treatments under field conditions. Penetrometer resistance was 1–2 MPa greater in the surface 30 cm of the compacted plots at a water content of 17–20% (v/v). Root thickening in response to compaction varied among genotypes and was negatively associated with rooting depth at one field site under non-compacted plots. Thickening was not associated with rooting depth on compacted plots. Genotypic variation in root anatomy was related to rooting depth. Deeper-rooting plants were associated with reduced cortical cell file number in combination with greater mid cortical cell area for node 3 roots. For node 4, roots with increased aerenchyma were deeper roots. A greater influence of anatomy on rooting depth was observed for the thinner root classes. We found no evidence that root thickening is related to deeper rooting in compacted soil; however, anatomical traits are important, especially for thinner root classes

Is the even distribution of insecticide-treated cattle essential for tsetse control? Modelling the impact of baits in heterogeneous environments

CITATION: Torr, S. J. & Vale, G. A. 2011. Is the even distribution of insecticide-treated cattle essential for tsetse control? Modelling the impact of baits in heterogeneous environments. PLoS Neglected Tropical Diseases, 5(10): e1360, doi:10.1371/journal.pntd.0001360.The original publication is available at http://journals.plos.org/plosntdsBackground Eliminating Rhodesian sleeping sickness, the zoonotic form of Human African Trypanosomiasis, can be achieved only through interventions against the vectors, species of tsetse (Glossina). The use of insecticide-treated cattle is the most cost-effective method of controlling tsetse but its impact might be compromised by the patchy distribution of livestock. A deterministic simulation model was used to analyse the effects of spatial heterogeneities in habitat and baits (insecticide-treated cattle and targets) on the distribution and abundance of tsetse. Methodology/Principal Findings The simulated area comprised an operational block extending 32 km from an area of good habitat from which tsetse might invade. Within the operational block, habitat comprised good areas mixed with poor ones where survival probabilities and population densities were lower. In good habitat, the natural daily mortalities of adults averaged 6.14% for males and 3.07% for females; the population grew 8.4× in a year following a 90% reduction in densities of adults and pupae, but expired when the population density of males was reduced to <0.1/km2; daily movement of adults averaged 249 m for males and 367 m for females. Baits were placed throughout the operational area, or patchily to simulate uneven distributions of cattle and targets. Gaps of 2–3 km between baits were inconsequential provided the average imposed mortality per km2 across the entire operational area was maintained. Leaving gaps 5–7 km wide inside an area where baits killed 10% per day delayed effective control by 4–11 years. Corrective measures that put a few baits within the gaps were more effective than deploying extra baits on the edges. Conclusions/Significance The uneven distribution of cattle within settled areas is unlikely to compromise the impact of insecticide-treated cattle on tsetse. However, where areas of >3 km wide are cattle-free then insecticide-treated targets should be deployed to compensate for the lack of cattle.http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0001360Publisher's versio

Cenozoic evolution of the eastern Black Sea: a test of depth-dependent stretching models

Subsidence analysis of the eastern Black Sea basin suggests that the stratigraphy of this deep, extensional basin can be explained by a predominantly pure-shear stretching history. A strain-rate inversion method that assumes pure-shear extension obtains good fits between observed and predicted stratigraphy. A relatively pure-shear strain distribution is also obtained when a strain-rate inversion algorithm is applied that allows extension to vary with depth without assuming its existence or form. The timing of opening of the eastern Black Sea, which occupied a back-arc position during the closure of the Tethys Ocean, has also been a subject of intense debate; competing theories called for basin opening during the Jurassic, Cretaceous or Paleocene/Eocene. Our work suggests that extension likely continued into the early Cenozoic, in agreement with stratigraphic relationships onshore and with estimates for the timing of arc magmatism. Further basin deepening also appears to have occurred in the last 20 myr. This anomalous subsidence event is focused in the northern part of the basin and reaches its peak at 15–10 Ma. We suggest that this comparatively localized shortening is associated with the northward movement of the Arabian plate. We also explore the effects of paleowater depth and elastic thickness on the results. These parameters are controversial, particularly for deep-water basins and margins, but their estimation is a necessary step in any analysis of the tectonic subsidence record stored in stratigraphy. <br/

Energy loss rates of two-dimensional hole gases in inverted Si/Si0.8Ge0.2 heterostructures

We have investigated the energy loss rate of hot holes as a function of carrier temperature TC in p-type inverted modulation-doped (MD) Si/SiGe heterostructures over the carrier sheet density range (3.5–13)×1011 cm–2, at lattice temperatures of 0.34 and 1.8 K. It is found that the energy loss rate (ELR) depends significantly upon the carrier sheet density, n2D. Such an n2D dependence of ELR has not been observed previously in p-type SiGe MD structures. The extracted effective mass decreases as n2D increases, which is in agreement with recent measurements on a gated inverted sample. It is shown that the energy relaxation of the two-dimensional hole gases is dominated by unscreened acoustic phonon scattering and a deformation potential of 3.0±0.4 eV is deduced

An independent evaluation of the modernization of NHS endoscopy services in England: data poverty and no improvement

Rationale, aims and objectives The Modernising Endoscopy Services (MES) programme introduced a focussed modernization drive and data collection regime to English NHS endoscopy services. We independently evaluated the MES programme by comparing routinely collected, service-related endoscopy data from sites that participated in the MES programme and sites that did not. Methods A random selection of 10 endoscopy units who had participated in the MES programme (intervention sites) were compared with a random selection of 10 endoscopy units who redesigned their services independently (control sites). Data on demand, numbers waiting, activity and cancellations were collected for eight time points between January 2003 and April 2006. Data were aggregated into intervention and control groups for statistical analysis using a two-way analysis of variance. Activity data were validated using an equivalent Hospital Episode Statistics dataset. Results Data were not routinely collected by 11 of 19 endoscopy units. Trust-held datasets were subsequently included to address problems with data availability. The accuracy of the Activity data was successfully validated. Statistical analysis of the data showed that neither the intervention group nor the control group were able to significantly improve their services over time. There was also no significant difference between the intervention group and the control group in the improvement of their endoscopy services at any point time. Conclusions Based on the data collected, the intervention programme did not significantly improve NHS endoscopy services in England over and above what could have been achieved independently with only the intention to redesign

Parallel distractor rejection as a binding mechanism in search

The relatively common experimental visual search task of finding a red X amongst red O’s and green X’s (conjunction search) presents the visual system with a binding problem. Illusory conjunctions (ICs) of features across objects must be avoided and only features present in the same object bound together. Correct binding into unique objects by the visual system may be promoted, and ICs minimized, by inhibiting the locations of distractors possessing non-target features (e.g., Treisman and Sato, 1990). Such parallel rejection of interfering distractors leaves the target as the only item competing for selection; thus solving the binding problem. In the present article we explore the theoretical and empirical basis of this process of active distractor inhibition in search. Specific experiments that provide strong evidence for a process of active distractor inhibition in search are highlighted. In the final part of the article we consider how distractor inhibition, as defined here, may be realized at a neurophysiological level (Treisman and Sato, 1990)