| 1. |
- Cervino, L. I., et al.
(author)
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An in vitro study for the dosimetric and radiobiological validation of respiratory gating in conventional and hypofractionated radiotherapy of the lung: effect of dose, dose rate, and breathing pattern
- 2019
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In: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 64:13
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Journal article (peer-reviewed)abstract
- Stereotactic body radiotherapy (SBRT) of the lung has become a standard of care for early-stage inoperable non-small cell lung cancer (NSCLC). A common strategy to manage respiratory motion is gating, which inevitably results in an increase in treatment time, especially in irregularly-breathing patients. Flattening-filter free (FFF) beams allow for delivery of the treatment at a higher dose rate, therefore counteracting the lengthened treatment time due to frequent interruption of the beam during gated radiotherapy. In this study, we perform our in vitro evaluation of the dosimetric and radiobiological effect of gated lung SBRT with simultaneous integrated boost (SIB) using both flattened and FFF beams. A moving thorax-shaped phantom with inserts and applicators was used for simulation, planning, gated treatment delivery measurements and in vitro tests. The effects of gating window, dose rate, and breathing pattern were evaluated. Planned doses represented a typical conventional fractionation, 200 cGy per fraction with SIB to 240 cGy, flattened beam only, and SBRT, 800 cGy with SIB to 900 cGy, flattened and FFF beams. Ideal, as well as regular and irregular patient-specific breathing patterns with and without gating were used. A survival assay for lung adenocarcinoma A549 cell line was performed. Delivered dose was within 6% for locations planned to receive 200 and 800 cGy and within 4% for SIB locations. Time between first beam-on and last beam-off varied from approximately 1.5 min for conventional fractionation, 200/240 cGy, to 10.5 min for gated SBRT, 800/900 cGy doses, flattened beam and irregular breathing motion pattern. With FFF beams dose delivery time was shorter by a factor of 2-3, depending on the gating window and breathing pattern. We have found that, for the most part, survival depended on dose and not on dose rate, gating window, or breathing regularity.
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| 2. |
- Coope, G.R., et al.
(author)
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Regional differences in the Lateglacial climate of northern Europe based on coleopteran analysis.
- 1995
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In: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 10:4, s. 391-395
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Journal article (peer-reviewed)abstract
- The termination of the Last Glaciation, the Lateglacial period, was characterised by highly unstable climates which, in northern Europe, oscillated between warm temperate and arctic conditions. Different indicators of past climate have provided contrasting views an the timing and intensity of these climatic changes. Here we present preliminary reconstructions of the thermal climate interpreted from subfossil coleopteran assemblages from Britain, Norway, Sweden and Poland, in which regional differences can be ascribed to the varying influence of, (a) the North Atlantic surface water temperatures, (b) the proximity of the Fennoscandian ice sheet and (c) the ice free continent. Quantification of the thermal climate enables these local differences to be resolved.
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| 3. |
- Coope, G.R., et al.
(author)
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Temperature gradients in northern Europe during the last glacial-Holocene transition (14-9 14C kyr BP) interpreted from coleopteran assemblages.
- 1998
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In: Journal of Quaternary Science. - 0267-8179 .- 1099-1417. ; 13:5, s. 419-433
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Journal article (peer-reviewed)abstract
- Late-glacial and early Holocene climatic conditions have been reconstructed for northern Europe using the mutual climatic range (MCR) palaeoclimate method based on fossil coleopteran assemblages. Altogether, beetle faunas from 77 sites have been analysed ranging from Ireland in the west to Poland and Finland in the east, and MCR estimates calculated. The results are plotted on 16 maps, each representative of a selected time-slice covering the period from 14.5 C-14 kyr BP to 9.0 C-14 kyr BP. Eight of the maps show the MCR estimates of T-max (mean temperature of the warmest month) derived from each site for which data are available, while the remainder show estimated T-max isotherms interpolated from these values. It can be demonstrated that at times the thermal climate was fairly uniform throughout the study area, whereas at others temperature gradients were much steeper than they are in the region today. There also appears to be a distinct contrast between cold periods, when contours trended NW-SE, and warmer periods, when contours trend W-E or even NE-SW. The pattern of climatic changes that emerges is shown to be very different from the traditional view that has been used up to now as a template for classifying Late-glacial climatic events on a wide, even global, scale. The suddenness and intensity of changes in the thermal climate may have been partially responsible for an apparent lack of equilibrium between the flora and fauna of the time and the physical environment in which they lived.
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| 7. |
- Hajdas, I., et al.
(author)
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Radiocarbon and absolute chronology of the Late-Glacial record from Hauterive/Rouges-Terres, Lake Neuchdtel (CH)
- 2004
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In: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 223, s. 308-312
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Journal article (peer-reviewed)abstract
- Radiocarbon ages of 87 samples made up of terrestrial macrofossils (mainly twigs of Salix sp.) were washed out from sediments sampled at Hauterive/Rouges-Terres, Lake Neuchatel, Switzerland, and measured using the AMS dating technique. These radiocarbon ages, which range from 8000 to 14,500 BP, were used to construct an absolute chronology of the record. A model of a sequence with known calendar ages for the period between 9000 to 17,500 cal BP was used to calibrate the 14 C ages. Three known calendar ages were set by pollen based dating (biozones) of palaeoclimatic events at 11,450 cal BP (Younger Dryas/Preboreal), 13,450 cal BP (Gerzensee Oscillation) and 14,650 cal BP (Oldest Dryas/ Bolling; see figure). This study shows that high resolution radiocarbon dating combined with such a calibration approach provides a powerful tool for dating stratigraphic sections by minimizing effects such as inversions in calendar ages and large errors caused by wiggles and plateaus in the radiocarbon time-scale.
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| 8. |
- Lemdahl, Geoffrey, et al.
(author)
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BEETLE RECORDS : Late Pleistocene of Europe
- 2007
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In: Encyclopedia of Quaternary Science. - : Elsevier. - 9780444527479 ; , s. 190-196
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Book chapter (other academic/artistic)abstract
- The Upper Pleistocene period spans the time from the last (Eemian, Ipswichian) interglacial period, 120 ka, to the termination of the last (Weichselian, Devensian) glaciation 11.5 ka. It was characterized by a complex sequence of climatic oscillations that ranged from glacial episodes, when ice sheets covered much of the Northern Hemisphere, to interglacial and interstadial intervals when the climate was often as warm as, or warmer than, that of the present day. Each of these events disrupted the biological systems so that many species had to alter their geographical ranges in order to track acceptable climates from one place to another across the continent. These movements of species enable estimates to be made of the terrestrial climatic history of the period. Among the most valuable of climatic indicators are the Coleoptera (beetles) whose robust exoskeletons are readily preserved in waterlogged sediments. Using the well-known mutual climatic range method on species from fossil beetle assemblages, it has been possible to make quantified estimates of the thermal climatic conditions during various phases of the Quaternary in western Europe. These show that, during warmer intervals, mean July temperatures were at least 3° C warmer than now, and winter figures were not much different from those of the present day. During the colder episodes, the mean July temperatures were at least 7° C colder than the present and winter temperatures were very much colder and of Siberian intensity. Rates of change from one climatic regime to another were often very rapid and may have involved a rise in summer temperature of 1° C per decade.
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| 9. |
- Lemdahl, Geoffrey, et al.
(author)
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BEETLE RECORDS : Late Pleistocene of Europe
- 2013. - 2:nd
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In: Encyclopedia of Quaternary Science. - : Elsevier. - 9780444536426 ; , s. 200-206
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Book chapter (other academic/artistic)abstract
- The Upper Pleistocene period spans the time from the last (Eemian, Ipswichian) interglacial period, 120 ka, to the termination of the last (Weichselian, Devensian) glaciation 11.5 ka. It was characterized by a complex sequence of climatic oscillations that ranged from glacial episodes, when ice sheets covered much of the Northern Hemisphere, to interglacial and interstadial intervals when the climate was often as warm as, or warmer than, that of the present day. Each of these events disrupted the biological systems so that many species had to alter their geographical ranges in order to track acceptable climates from one place to another across the continent. These movements of species enable estimates to be made of the terrestrial climatic history of the period. Among the most valuable of climatic indicators are the Coleoptera (beetles) whose robust exoskeletons are readily preserved in waterlogged sediments. Using the well-known mutual climatic range method on species from fossil beetle assemblages, it has been possible to make quantified estimates of the thermal climatic conditions during various phases of the Quaternary in western Europe. These show that, during warmer intervals, mean July temperatures were at least 3° C warmer than now, and winter figures were not much different from those of the present day. During the colder episodes, the mean July temperatures were at least 7° C colder than the present and winter temperatures were very much colder and of Siberian intensity. Rates of change from one climatic regime to another were often very rapid and may have involved a rise in summer temperature of 1° C per decade.
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