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BACKGROUND The association between travel time from the tertiary care centre and outcomes after aortic surgery is unknown. Our objective was to determine the effect of estimated travel time from tertiary care centre on outcomes in ascending aortic repair in Nova Scotia. METHODS AND RESULTS A retrospective analysis of all elective and emergent ascending thoracic aortic operations, performed either in isolation or in combination with other cardiac surgery procedures, from 2005 and 2015 was carried out. Clinical characteristics as well as in-hospital outcomes were recorded. Patient's residential geographical coordinates were used to calculate estimated driving time using geographic information system software (ArcMAP, ESRI). Socioeconomic deprivation quintiles were derived from the 2006 Census based on the patient's residential postal code. Long-term survival was identified through Vital Statistics database. Multivariable logistic regression was performed to determine the independent effect of estimated travel time ≥1 hour on in-hospital outcomes. Cox-proportional hazard modeling and Kaplan-Meier survival estimates were created to determine the independent effect of estimated travel time on long-term survival. A total of 476 patients underwent ascending thoracic aortic surgery from 2005 to 2015. Mean age was 59.1 (±13.3) years and 107 (22.5%) were female. Compared to patients at CONCLUSION Compared to patients who live in close proximity to the tertiary centre, patients at increased travel time experience equivalent in-hospital outcomes but decreased long-term survival following ascending aortic operations. Resource expansion to improve follow-up monitoring of patients who live remotely is needed.

Bioinformatics blossomed with research developments in molecular biology. But as the focus of research moves back up the physical scale to the biology of whole multicellular organisms, there are new integration challenges. Data integration is a perennial theme that will not be explored here. Rather, we outline a survey of the types of data generated in whole organisms, putting particular emphasis on complex image capture, management and analysis, bio-systems modelling techniques at this higher scale, and approaches to integrating models across these physical scales. This change in biological focus raises certain challenges, one of which may be the need to retrain bioinformaticians in sciences pertaining to whole plants and animals.

Ventilatory acclimatization to hypoxia is associated with an increase in ventilation under conditions of acute hyperoxia (V˙e hyperoxia) and an increase in acute hypoxic ventilatory response (AHVR). This study compares 48-h exposures to isocapnic hypoxia ( protocol I) with 48-h exposures to poikilocapnic hypoxia ( protocol P) in 10 subjects to assess the importance of hypocapnic alkalosis in generating the changes observed in ventilatory acclimatization to hypoxia. During both hypoxic exposures, end-tidal [Formula: see text] was maintained at 60 Torr, with end-tidal [Formula: see text] held at the subject’s prehypoxic level ( protocol I) or uncontrolled ( protocol P).V˙e hyperoxiaand AHVR were assessed regularly throughout the exposures.V˙e hyperoxia( P < 0.001, ANOVA) and AHVR ( P < 0.001) increased during the hypoxic exposures, with no significant differences between protocols I and P. The increase inV˙e hyperoxiawas associated with an increase in slope of the ventilation-end-tidal [Formula: see text] response ( P < 0.001) with no significant change in intercept. These results suggest that changes in respiratory control early in ventilatory acclimatization to hypoxia result from the effects of hypoxia per se and not the alkalosis normally accompanying hypoxia.

Distinguished plant ecologist A. G. Tansley (1871–1955) is widely considered to be the father of British ecology. He was one of the founding members of the British Ecological Society and during his career he edited two important journals on the subject: The New Phytologist and the Journal of Ecology. He was also part of a committee formed in 1904 to survey systematically the vegetation of the British Isles. This book, edited by Tansley and first published in 1911, is the result of that survey. It contains contributions by leading botanists of the early twentieth century, and contains detailed maps, photographs and figures. The physical characteristics and climate of Britain are outlined early in the book and later the plant communities of particular areas such as moors, fens and the coast are discussed. This is a significant work that will appeal to both plant ecologists and natural historians.

THE movemennt against pure science and against freedom in science was first brought to Great Britain by the Soviet delegation to the International Congress on the History of Science held in London in 1931. Before that time it was accepted as a matter of course that the pursuit of pure science by independent research was a worthy and admirable thing, that it was desirable for qualified people to devote their lives to the increase of knowledge as an end in itself, and that research workers at universities should have full liberty to choose the -subjects of their own investigations. One may search the literature in vain for any contrary view, and no such view can have been held by more than a minute fraction of the scientific world.

During acclimatization to the hypoxia of altitude, the cerebral circulation is exposed to arterial hypoxia and hypocapnia, two stimuli with opposing influences on cerebral blood flow (CBF). In order to understand the resultant changes in CBF, this study examined the responses of CBF during a period of constant mild hypoxia both with and without concomitant regulation of arterial P(CO2). Nine subjects were each exposed to two protocols in a purpose-built chamber: (1) 48 h of isocapnic hypoxia (Protocol I), where end-tidal P(O2) (P(ET,O2)) was held at 60 Torr and end-tidal P(CO2) (P(ET,CO2)) at the subject's resting value prior to experimentation; and (2) 48 h of poikilocapnic hypoxia (Protocol P), where P(ET,O2) was held at 60 Torr and P(ET,CO2) was uncontrolled. Transcranial Doppler ultrasound was used to assess CBF. At 24 h intervals during and after the hypoxic exposure CBF was measured and the sensitivity of CBF to acute variations in P(O2) and P(CO2) was determined. During Protocol P, P(ET,CO2) decreased by 13% (P < 0.001) and CBF decreased by 6% (P < 0.05), whereas during Protocol I, P(ET,CO2) and CBF remained unchanged. The sensitivity of CBF to acute variations in P(O2) and P(CO2) increased by 103% (P < 0.001) and 28% (P < 0.01), respectively, over the 48 h period of hypoxia. These changes did not differ between protocols. In conclusion, CBF decreases during mild poikilocapnic hypoxia, indicating that there is a predominant effect on CBF of the associated arterial hypocapnia. This fall occurs despite increases in the sensitivity of CBF to acute variations in P(O2)/P(CO2) arising directly from the hypoxic exposure.

During an 8 h period of either isocapnic or poikilocapnic hypoxia, tests of the acute ventilatory response to hypoxia (AHVR) have shown that there is an increase in hypoxic sensitivity (2) accompanied by an increase in ventilation under conditions of acute hyperoxia (3). These changes were similar between the two protocols suggesting a direct effect of hypoxia per se.

This study examines the effects of prolonged hypoxia, with and without control of end-tidal CO2 partial pressure (PET,CO2), on the intensity-weighted mean velocity of blood flow in the middle cerebral artery (VIWM) and on heart rate (HR). Specifically, the time course of the responses, their reversibility with brief periods of hyperoxia and the recovery phase following prolonged hypoxia were all investigated. Twelve subjects were studied, of whom nine provided satisfactory data. A purpose-built chamber was used for the prolonged control of the end-tidal gases, and an end-tidal forcing system was used for generating the brief variations in end-tidal gases. Three 16 h protocols were employed: (1) 8 h eucapnic (average PET,CO2 = 39 mmHg) hypoxia (end-tidal O2 partial pressure, PET,O2 = 55 mmHg) followed by 8 h eucapnic euoxia (PET,O2 = 100 mmHg); (2) 8 h poikilocapnic (average PET,CO2 4 mmHg below eucapnia) hypoxia (PET,O2 = 55 mmHg) followed by 8 h poikilocapnic euoxia (PET,O2 = 100 mmHg); and (3) control (air inspired throughout). VIWM (using Doppler ultrasound) and HR were measured during brief exposures to hypoxic/euoxic and hyperoxic conditions with PET,CO2 held 1-2 mmHg above eucapnia, at 0, 20, 240 and 480 min in the first 8 h, and at the same times in the second 8 h. There were no significant trends in VIWM under hypoxic conditions for either hypoxic protocol (ANOVA) and no significant differences between the three protocols for VIWM in hyperoxia (ANOVA). In contrast to VIWM, there was a significant increase in HR over time during both hypoxic exposures (P < 0.01, ANOVA). HR increased to a similar extent for the two types of hypoxia, and there was some suggestion that HR remained elevated after the relief of hypoxia. The results suggest that, with the level of hypoxia employed, progressive changes in HR occur, but that this level and duration of hypoxia has little sustained effect on VIWM.

Tansley, J. G., C. Clar, M. E. F. Pedersen, and P. A. Robbins. Human ventilatory response to acute hyperoxia during and after 8 h of both isocapnic and poikilocapnic hypoxia. J. Appl. Physiol. 82(2): 513–519, 1997.—During 8 h of either isocapnic or poikilocapnic hypoxia, there may be a rise in ventilation (V˙e) that cannot be rapidly reversed with a return to higher[Formula: see text] (L. S. G. E. Howard and P. A. Robbins. J. Appl. Physiol. 78: 1098–1107, 1995). To investigate this further, three protocols were compared: 1) 8-h isocapnic hypoxia [end-tidal[Formula: see text]([Formula: see text] ) held at prestudy value, end-tidal [Formula: see text]([Formula: see text]) = 55 Torr], followed by 8-h isocapnic euoxia[Formula: see text] = 100 Torr); 2) 8-h poikilocapnic hypoxia followed by 8-h poikilocapnic euoxia; and 3) 16-h air-breathing control. Before and at intervals throughout each protocol, theV˙e response to eucapnic hyperoxia [Formula: see text] held 1–2 Torr above prestudy value,[Formula: see text] = 300 Torr) was determined. There was a significant rise in hyperoxicV˙e over 8 h during both forms of hypoxia ( P < 0.05, analysis of variance) that persisted during the subsequent 8-h euoxic period ( P < 0.05, analysis of variance). These results support the notion that an 8-h period of hypoxia increases subsequent hyperoxic V˙e, even if acid-base changes have been minimized through maintenance of isocapnia during the hypoxic period.

Arthur Harry Church was born on 28 M arch, 1865, the son of a Plymouth saddler. At the age of 16 he became a pupil teacher at Ashburton Grammar School, and at 20 entered University College, Aberystwyth, where he stayed four years, taking the London B.Sc. degree. He then gained a science scholarship at Jesus College, Oxford, coming into residence in 1891, and the whole of the rest of his life was spent in the University city. In 1894 Church graduated in the first class of the Honour School of Botany, and in the same year was appointed demonstrator in the Department of Botany by Vines, who was then Sherardian Professor. In 1894 he took the London degree of D.Sc., from 1908 to 1912 was a Research Fellow of Jesus College, in 1921 was elected a Fellow of the Royal Society, and from 1908 till his retirement under the age limit in 1930 he held the title of Lecturer in Botany. Thus for 36 years Church worked as teacher and investigator in one University Department. He died at his house in Oxford on 24 April 1937, aged 72.

More than fifty years ago I read to the Linnean Society a paper on this subject, prepared in collaboration with Miss Elizabeth Dale. I was somewhat dissatisfied with it at the time because of the number of 'loose threads' involved in the complex problems of variation in which I was then interested, and I did not see how to follow them up; so the paper was never submitted for publication. In the middle nineties of the last century the subject of variation was very prominent in the minds of biologists. Bateson's thick volume, Materials for the Study of Variation, had recently been published, and controversy raged between those who thought that 'continuous' variation was the main, if not the only, material on which natural selection worked and those who stressed the importance of 'discontinuous' variation in evolution. It was, of course, before Johannsen's work on the non-inheritance of 'continuous' (fluctuating) variation, and before the rediscovery of Mendel's work and the revolution which it brought into this whole field. My attention had been attracted by the constant occurrence of a small percentage of pentamerous flowers in the common tormentil, Potentilla erecta (then usually known as Potentilla Tormentilla), whose normal 4-petalled flowers are familiar to everyone, since the tormentil is one of the most widely distributed and commonest plants in rough grazings, heathlands and moorlands on the lighter non-calcareous soils throughout the country. Influenced by the notion that particular environmental conditions, such for instance as soil differences, water supply, local climate, or aspect, might affect this kind of variation Miss Dale and I collected and examined a large number of flowers from various sites in different parts of the country, but got no clear indications of any such effects. I did, however, conclude that the plant produces more pentamerous flowers at the outset of its flowering season than later in the summer. Thus I observed IO-I2z% of pentamerous flowers borne by luxuriant plants with long shoots which had grown up through gorse bushes and just opened their first flowers in June, at a time when the plants growing in grazed turf, and thus fully exposed to light from the first, had been flowering for some weeks. It is possible that the large proportion of pentamerous flowers (about four times the normal percentage) on these plants growing among gorse was connected with their luxuriance, but the correlation with early production is confirmed by the larger proportion of pentamerous flowers observable in early May, when fully exposed tormentils begin to flower, than later in the season. Further confirmation was obtained by observing the symmetry of successively opening flowers in pot cultures. Unfortunately, no systematic observations were made on the distribution on individual plants or on the seasonal distribution of variation in the symmetry of the flowers. It may be conjectured that pentamerous flowers are largely the terminal flowers of the main flowering axes, as

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Sigmund Freud was bom of a Jewish family at Freiberg in Moravia on 6 May 1856. At the age of four he was taken to Vienna and that city was his home till 1938, when the Nazi occupation compelled him to leave Austria. He arrived in England in June and lived at Hampstead till he died on 23 September 1939. Freud records that he was top of his class at the Gymnasium for seven years, that he enjoyed special privileges and was required to pass scarcely any examinations. His father insisted that in his choice of a profession he should follow his own inclination, but neither at that time nor in later life did he feel any particular predilection for the career of a physician. Rather was he moved by what he describes as ‘a sort of curiosity’, which was directed more towards human concerns than towards natural objects. At one time, influenced by an older school friend, he wished to study law and to engage in social activities. But he was also strongly attracted by the theories of Darwin, for, as he says, ‘they held out hopes of an extraordinary advance in our understanding of the world’. It was hearing Goethe’s essay on Nature read aloud just before he left school that decided him to become a medical student.