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Radiation-induced lung injury remains a significant toxicity in thoracic radiotherapy. Because a precise diagnosis is difficult and commonly used assessment scales are unclear and subjective, there is a need to establish quantitative and sensitive grading methods. The lung tissue density change expressed in Hounsfield units (HUs) derived from CT scans seems a useful numeric surrogate. The study aimed to confirm a dose-response effect on HU value changes (ΔHU), their evolution in time, and the impact of selected clinical and demographic factors. We used dedicated, self-developed software to register and analyze 120 pairs of initial and follow-up CT scans of 47 lung cancer patients treated with dynamic arc radiotherapy. The differences in HU values between CT scans were calculated within discretized dose-bins limited by isodose lines. We have proved the dose-effect relationship, which is well described with a sigmoid model. We found the time evolution of HU changes to suit a typical clinical presentation of radiation-induced toxicity. Some clinical factors were found to correlate with ΔHU degree: planning target volume (PTV), V35 in the lung, patient's age and a history of arterial hypertension, and initial lung ventilation intensity. Lung density change assessment turned out to be a sensitive and valuable method of grading post-RT lung toxicity. [ABSTRACT FROM AUTHOR]

This paper aims at developing a technique for observing the frost heaving process in soil nondestructively and microscopically using an industrial micro-focus X-ray CT scanner. For this purpose, a compact frost heaving apparatus that could freeze the soil in one dimension inside the X-ray CT scanner was developed. This experimental method made it possible to observe the process of ice lens formation in the soil and the shape of the ice lens in detail. In highly frost susceptible weathered volcanic ash, ice lenses like multiple cracks were observed to develop in the early stages of the experiment. When the freezing front was stagnant and the heat was balanced, thick and well-developed ice lenses could be observed. The shape of the ice lens observed in the weathered volcanic ash without gravel was relatively flat. In the terrace deposits containing gravel, ice lenses were observed to be formed from around the larger particles. Furthermore, the formed ice lenses were more uneven in shape than weathered volcanic ash. In the case of volcanic ash sand composed of coarse grains that do not have frost susceptibility, no frost heaving occurred and no ice lenses were observed. The gray levels of the frozen areas of the weathered volcanic ash and terrace deposits with frost susceptibility were found to decrease. This is thought to be because the precipitation of ice lenses in the soil pushed the soil particles apart and reduced their density relatively. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the changes in abundance, species richness, and diversity of epiphytic Gastrotricha in the littoral of a mesotrophic lake. The influence of pH and oxygen on their occurrence was also investigated. Gastrotricha occurred throughout the year: 27 species were identified together, and species richness varied at different seasons. The highest number of species on water vegetation was found in the summer (26 species), while in the winter season only 7 species were present. Species diversity expressed by the Shannon index, in spring, summer, and autumn was high and amounted 2.10, 2.37, and 2.31, respectively. In winter, the value of the index was significantly lower and amounted 0.59. Three species were found to be dominant from spring to autumn with the dominance over 9.0%: Heterolepidoderma macrops Kisielewski, 1981, H. ocellatum (Mecˇnikow, 1865), and Lepidodermella squamata (Dujardin, 1841). The GLM analysis revealed that number of collected species in spring, summer, and autumn does not depend either on season or on pH and oxygen content. The lowest density of gastrotrichs was found in winter (average of 33 103 indiv. m2 ), whereas the highest was found in summer (average of 1392 103 indiv. m2 ). The density differed with season and neither pH nor oxygen content had an effect upon gastrotrich densities. [ABSTRACT FROM AUTHOR]

LiDAR full-waveform provides a better description of the physical and forest vertical structure properties than discrete LiDAR since it registers the full wave that interacts with the canopy. In this paper, the effect of flight line side-lap is analysed on forest structure and canopy fuel variables estimations. Differences are related to pulse density changes between flight stripe side-lap areas, varying the point density between 2.65 m-2 and 33.77 m-2 in our study area. These differences modify metrics extracted from data and therefore variable values estimated from these metrics such as forest stand variables. In order to assess this effect, 64 pairwise samples were selected in adjacent areas with similar canopy structure, but having different point densities. Two parameters were tested and evaluated to minimise this effect: voxel size and voxel value assignation testing maximum, mean, median, mode, percentiles 90 and 95. Student's t-test or Wilcoxon test were used for the comparison of paired samples. Moreover, the absolute value of standardised paired samples was calculated to quantify dissimilarities. It was concluded that optimizing voxel size and voxel value assignation minimised the effect of point density variations and homogenised full-waveform metrics. Height/median ratio (HTMR) and Vertical distribution ratio (VDR) had the lowest variability between different densities, and Return waveform energy (RWE) reached the best improvement with respect to initial data, being the difference between standardised paired samples 1.28 before and 0.69 after modification. [ABSTRACT FROM AUTHOR]

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The present study was undertaken to evaluate the regeneration of bone in the extraction socket by using computer- assisted densitometric image analysis (CADIA) in 10 patients with bilateral symmetrical mandibular third molar impactions, after extraction. In one side hydroxyapatite (HA) was placed into the socket and on the other side no graft was placed. Standardized intraoral periapical radiograph (IOPA) and orthopantomograph (OPG) were taken, 15 days postoperatively, and at 3 and 6 months interval. These radiographs were scanned by using CADIA and images were compared, which showed more density on the graft side. The radiographic data were compared to clinical parameters. The results indicated that CADIA may be useful in assessing the bone density changes in an extraction socket. [ABSTRACT FROM AUTHOR]

Grey partridge Perdix perdix populations were monitored in the years 1991–2004 in ten agricultural areas (100–200 km2 each) located in various regions of Poland. Spring density (call counts in March/April) and parameters describing reproductive success (counts of adult and young birds in coveys found in August) were estimated, and annual survival rate of adult birds was calculated. In the 1990s, the mean spring density of grey partridge in Poland showed a threefold decrease. In 1993 (the year of the highest mean density), from 4.6 pairs/km2 to 20.0 pairs/km2 were found in individual areas; whereas in 2004, there were from 0.4 pairs/km2 to 8.3 pairs/km2. The mean brood-production rate in individual years ranged from 29% to 49% (overall mean 36.8%), the chick-survival rate from 31% to 56% (43.1%), the young production from 1.6 to 2.8 young per adult (2.32 young/adult) and the annual survival rate of adult birds from 25% to 33% (28.3%). The population decrease in the 1990s was connected with the drop of reproductive success, including both the brood-production rate and the chick-survival rate, as well as with the decline of annual survival rate of adult birds. The decrease of brood-production rate and adult-survival rate probably resulted mainly from increased abundance of nest and incubating female predators (particularly foxes). Fluctuations in chick-survival rate were related to weather conditions, but also slight long-term decline was recorded, probably due to more intensive pesticide use. [ABSTRACT FROM AUTHOR]

Temporal gravity changes provide information about mass and/or density variations within and below the volcano edifice. Three active volcanoes have been under investigation; each of them related to a plate boundary: Mayon/Luzon/Philippines, Merapi/Java/Indonesia, and Galeras/Colombia. The observed gravity changes are smaller than previously expected but significant. For the three volcanoes under investigation, and within the observation period, mainly the increase of gravity is observed, ranging from 1,000 nm-2 to 1,600 nms-2. Unexpectedly, the gravity increase is confined to a rather small area with radii of 5 to 8 km around the summit. At Mayon and Merapi the parallel GPS measurements yield no significant elevation changes. This is crucial for the interpretation, as the internal pressure variations do not lead to significant deformation at the surface. Thus the classical Mogi-model for a shallow extending magma reservoir cannot apply. To confine the possible models, the attraction due to changes of groundwater level or soil moisture is estimated along the slope of Merapi exemplarily by 2-D modelling. Mass redistribution or density changes were evaluated within the vent as well as deeper fluid processes to explain the gravity variations; the results are compared to the model incorporating the additional effect of elastic deformation. [ABSTRACT FROM AUTHOR]