Occupying about 14 % of the world's surface, the Southern Ocean plays a fundamental role in ocean and atmosphere circulation, carbon cycling and Antarctic ice-sheet dynamics. Unfortunately, high ...interannual variability and a dearth of instrumental observations before the 1950s limits our understanding of how marine–atmosphere–ice domains interact on multi-decadal timescales and the impact of anthropogenic forcing. Here we integrate climate-sensitive tree growth with ocean and atmospheric observations on southwest Pacific subantarctic islands that lie at the boundary of polar and subtropical climates (52–54° S). Our annually resolved temperature reconstruction captures regional change since the 1870s and demonstrates a significant increase in variability from the 1940s, a phenomenon predating the observational record. Climate reanalysis and modelling show a parallel change in tropical Pacific sea surface temperatures that generate an atmospheric Rossby wave train which propagates across a large part of the Southern Hemisphere during the austral spring and summer. Our results suggest that modern observed high interannual variability was established across the mid-twentieth century, and that the influence of contemporary equatorial Pacific temperatures may now be a permanent feature across the mid- to high latitudes.
The New Zealand subantarctic islands of Auckland and Campbell,
situated between the subtropical front and the Antarctic Convergence in the
Pacific sector of the Southern Ocean, provide valuable ...terrestrial records
from a globally important climatic region. Whilst the islands show clear
evidence of past glaciation, the timing and mechanisms behind Pleistocene
environmental and climate changes remain uncertain. Here we present a
multidisciplinary study of the islands – including marine and terrestrial
geomorphological surveys, extensive analyses of sedimentary sequences, a
comprehensive dating programme, and glacier flow line modelling – to
investigate multiple phases of glaciation across the islands. We find
evidence that the Auckland Islands hosted a small ice cap
384 000 ± 26 000 years ago (384±26 ka), most likely during
Marine Isotope Stage 10, a period when the subtropical front was reportedly
north of its present-day latitude by several degrees, and consistent with
hemispheric-wide glacial expansion. Flow line modelling constrained by field
evidence suggests a more restricted glacial period prior to the LGM that
formed substantial valley glaciers on the Campbell and Auckland Islands around
72–62 ka. Despite previous interpretations that suggest the maximum glacial
extent occurred in the form of valley glaciation at the Last Glacial Maximum
(LGM; ∼21 ka), our combined approach suggests minimal LGM
glaciation across the New Zealand subantarctic islands and that no glaciers
were present during the Antarctic Cold Reversal (ACR; ∼15–13 ka).
Instead, modelling implies that despite a regional mean annual air
temperature depression of ∼5 ∘C during the LGM, a combination
of high seasonality and low precipitation left the islands incapable of
sustaining significant glaciation. We suggest that northwards expansion of
winter sea ice during the LGM and subsequent ACR led to precipitation
starvation across the middle to high latitudes of the Southern Ocean, resulting
in restricted glaciation of the subantarctic islands.
The advent of new imaging techniques is broadening our understanding of the major psychiatric illnesses. The increased knowledge of brain function will have consequences for the expert medical ...witness who has to give evidence in court. Both the insanity defence and the defence of automatism depend on disorders of the mind. Psychiatry is now able in many cases to produce evidence that these are consequent upon disorders of the brain. In presenting evidence in court there is an apparent conflict between 'brain words' and 'mind words'.
Minor episodes of aggressive behavior are relatively common in some populations of patients with epilepsy. However, they are probably no more common than in populations who are socially disadvantaged ...or who have brain damage. The confusion that commonly follows seizures can lead to apparently aggressive behavior. Rarely, the seizure itself may lead to directed aggression; very rarely does it lead to murderous attacks. Although post-ictal psychotic aggression is usually not severe, when it is driven by prominent delusions and hallucinations, it can result in self-destructive acts or serious violence. Clearly, however, it is quite unfair to globally classify epileptics as aggressive, and the time has come to abandon this stereotype.
Temporal stability of the relationship between a potential proxy climate record and the climate record itself is the foundation of palaeoproxy reconstructions of past climate variability. ...Dendroclimatologists have spent considerable effort exploring the issue of temporal instability of temperature records at high-latitude and −altitude Northern Hemisphere sites. Much of this work has focused on the Divergence Problem in which the modern ends of tree-ring chronologies exhibit pronounced departures from the climate-proxy relationships of preceding decades. However, there has been little scrutiny of how different methods might influence determinations of temporal instability at either the local scale or across broader spatial domains. Here we use four sets of Southern Hemisphere (SH) chronologies and three sets of synthetic data with known interventions to compare four methodologies that have been widely used to assess the temporal stability of relationships between tree-ring series and climate. Our analyses demonstrate that a determination of temporal instability may be partially dependent on method used to examine data, that some methods are more sensitive to standardisation choice than others, and that all methods are better at detecting high- rather than low-frequency instability. In all cases, the relatively modest strength of the relationships between the selected SH ring-width chronologies and temperature is likely to be an issue, especially if changes in trends are of interest. We recommend that robust assessment of temporal instability between tree-ring chronologies and observational climate data should use a range of methods and that unstable temporal relationships across space be carefully considered in the context of large climate field reconstructions.
Based on longitudinal research, this paper examines radical technological innovation in the Benefits Agency, which was central to the redesign of business strategy and to intended shifts in the ...management of the work of computer users. However, unrealised assumptions about the functionality of the new computer system created a serious misalignment between IT design, strategic performance targets and the intended strategy for managing labour. This required a process of learning by computer users, their line managers and senior management, one that pivoted on the performance goals that were seen as achievable within the opportunities and constraints afforded by the change programme. A labour strategy emerged out of the progressive alignment between these goals and an appropriate pattern of practices for the management of computer users, one at variance with strategic intentions founded on a smooth integration of technical and work systems. Moreover, this multilateral organisational learning not only transacted the constraints that were imposed by the business strategy, but also powerfully influenced its development in turn. As such, its key constituent elements of technology, structure and strategic performance objectives did not simply establish the conditions for the formation of labour strategy, but were significantly affected by the learning about their deficiencies and the necessary changes in them which were at its heart. Consequently, rather than simply flowing from “higher order” decisions, labour management was integral to the shaping of the organisation's business strategy over time.
The aim of the study was to identify possible disturbances of sensorimotor gating and habituation of the eye blink startle response, in patients with non-epileptic seizures (NES). Prepulse inhibition ...(PPI) of the startle reflex, as an operational measure of sensorimotor gating and habituation was studied in 21 patients with NES and in 22 healthy control subjects. Six NES patients were taking antiepileptic drugs at the time of testing. PPI was significantly impaired in the NES group compared to the control group, with deficits being greater in unmedicated patients. There was a trend for medicated NES patients to show higher PPI than unmedicated patients, but this was not significant. Habituation was intact in both medicated and unmedicated NES patients. It is proposed that deficits of information processing related to sensorimotor gating in patients with NES may be associated with abnormalities within the limbic system–basal ganglia circuitry which has been shown to be the substrate of `gating' assessed by PPI. It was also found that NES patients had greater psychopathology than the control group when rated by the Traumatic Symptom Checklist (TSC-40). Overall, the anxiety subscale was the only element that was negatively correlated with PPI. It is suggested that anxiety may contribute to impairment of PPI in patients with NES.
•New 1700-year Athrotaxis selaginoides chronology from southeastern Australia.•Chronology most strongly corresponds to temperature.•A. selaginoides and nearby temperature-sensitive L. franklinii ...chronologies differ.•Physiological differences likely to be important in these differences.•Composition of chronologies possibly related to different fire patterns at sites.
Few Southern Hemisphere tree-ring chronologies exceed 1000 years in length. We present a ca. 1700 years of indexed values for the long-lived conifer Athrotaxis selaginoides at Cradle Mt in southeastern Australia and compare it with the only other published millennial-plus length tree-ring chronology for Australia: the nearby Mt Read Lagarostrobos franklinii. We use simple correlation function and pointer year analyses to compare the climate responses of the two species (temperature, precipitation and growing degree days). Both chronologies show accelerated growth at their modern ends, but this growth acceleration is not synchronous, beginning approximately a quarter of a century earlier at the Cradle Mt site. This discrepancy may highlight the relevance of chronology composition and/or physiological differences in the species. Although the seasonality of the climatic responses of the two species is similar, that of A. selaginoides is generally weaker than that of L. franklinii. Somewhat paradoxically, the only pointer years in common between the chronologies are 1898 and 1908 CE. The periods from 600 to 900CE and ∼1200–1450CE are conspicuous for their absence of positive pointer years while no negative pointer years occur for either site from ∼1200–1350CE. It is possible that differing patterns of pointer years can be partially explained by a peak in establishment from ∼1150–1850CE at the Mt Read L. franklinii site compared to continuous establishment at Cradle Mt. Although statistically significant and time-stable climate responses for the A. selaginoides chronology are too weak to base a single-chronology climate reconstruction on, the long chronology will likely make an important contribution to future multi-proxy temperature reconstructions for southeastern Australia.
The efficiency of noiseless coding may be improved by coding extensions of the source; for large extensions the efficiency is arbitrarily close to unity. The paper shows that the efficiency is not ...always improved just by coding the next extension. In some cases the code of a larger extension is markedly less efficient than its predecessor, although always within the theoretical limits of efficiency. The author shows how the phenomenon arises from changes to the Huffman coding tree as the source probabilities change and investigates it for binary and ternary codes.< >
In a pilot study, SPECT was used to explore differences in rCBF between a group of patients with schizophrenia-like psychoses of epilepsy (SLPE) and a matched group of epileptic controls. Five ...patients in each group were investigated and those with SLPE showed significant reductions in the index of rCBF in the left medial temporal region. These differences are being investigated further.
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