Rate Of Volume Change Research Articles

A Stratigraphic Framework for the Preservation and Shredding of Environmental Signals

AbstractThe stratigraphic record contains unique information about past landscapes and environmental change. Whether landscapes faithfully transmit signals of environmental change to stratigraphy is unknown because autogenic processes, such as river avulsion, can obscure signals prior to long‐term stratigraphic storage. We develop a theoretical framework that predicts when a sediment flux signal will be transferred from the landscape to stratigraphy. This threshold magnitude is a function of signal duration. The magnitude is set by the maximum rate of autogenic volume change of the landscape, which decreases with increasing time window. Physical delta experiments, specifically designed to test our theory, demonstrate that only sediment supply signals with a magnitude greater than the threshold are stored in stratigraphy, supporting our theory. This framework allows us to assess the fidelity of the stratigraphic record to archive past signals of environmental change and predict the short‐ and long‐term impact of current anthropogenic forcing on landscapes.

Phase separation mechanism and property changes in In–41Sn–9Zn under the current stressing

Phase separation mechanism and property changes in In–41Sn–9Zn solder was investigated with the current density of direct current 1.0 × 103 A/cm2. The results indicated that the phase separation was affected by the combination of electron wind force and back stress. The different degree of lattice distortion between different regions was one of the causes of the back stress. In the alloy, In-rich β phases and Sn-rich γ phases were segregated at the cathode side and anode side respectively, while Zn atoms didn’t migrate to the two poles significantly. Sn was the main diffusing atom $$\left( {\left| {{\text{Z}}_{\text{Sn}}^{*} } \right| > \,\left| {{\text{Z}}_{\text{In}}^{*} } \right|} \right)$$ in the alloy, so the volume change rates at the anode side was about four times higher than that of the cathode side. After 72 h electromigration, the cathode–anode difference in micro-hardness, melting point, thermal enthalpy and melting interval was about 0.3 Mpa, 2 °C, 4.18 J/g, and 0.9 °C, respectively.

Growth characteristic of microbubble in a T-junction microchannel in microfluidic chip

Microbubble formation in a T-junction microchannel in polydimethylsiloxane (PDMS) microfluidic chip were developed. The experiment based on high-speed microscopic camera system was set up to investigate the effects of liquid flow rate, gas pressure and gas channel width on microbubble growth. Three stages of microbubble growth process were obtained through the experiment firstly. The control variable method was used for investigating the growth characteristics of microbubble, including volume change rate and the ratio of length to width. The present study provided an empirical reference for the growth of microbubble in microchannel, which helped to achieve precise control of microbubble volume.

Dynamic Volume Change Rate and Aspect Ratio Are Correlated to the Formation of an Irregular Morphology of Unruptured Intracranial Aneurysm.

The aim of this research was to study the factors influencing the formation of intracranial aneurysms with irregular morphology by observing the dynamic volume change rate of intracranial unruptured aneurysms and other aneurysm characteristics. Sixty-five unruptured intracranial aneurysms of 51 consecutive patients from 1 center were included in this study. All patients underwent a dual-source computed tomography electrocardiogram-gated 4-dimensional computed tomography angiography examination. The original data at the end of the scan were reconstructed, and 20 sets of data packages through a cardiac cycle with 5% interval were obtained. Data packages were processed by a 3-dimensional software workstation to obtain 20 sets of images and dynamic diagrams. The volume of each aneurysm in the 20 sets of images was measured, and the volume change was calculated by a specific formula. The other data features of the aneurysm such as aneurysm neck, aneurysm height, aspect ratio (AR), location at bifurcation, and clinical features such as age, sex, hypertension history, type 2 diabetes history, smoking history, family history, multiple aneurysm history, and subarachnoid hemorrhage history, were documented in detail. After single factor analysis data, logistic regression analysis of the meaningful indicator was conducted to study the predictive factors of irregular aneurysms. Of the 65 aneurysms, 25 possessed an irregular shape and 40 were of regular shape; 51 were anterior circulatory aneurysms and 14 were posterior circulatory aneurysms. Single factor analysis showed that AR (P = 0.001), volume change rate (P = 0.002), and location of aneurysm at the bifurcation (P = 0.038) of the vessel were significantly correlated with irregular aneurysms, but not correlated with age, sex, hypertension history, type 2 diabetes history, smoking history, family history, multiple aneurysm history, and subarachnoid hemorrhage history. Multifactor analysis showed that volume change rate greater than 30% (P = 0.008; odds ratio, 6.934) and AR greater than 1.4 (P = 0.004; odds ratio, 8.258) were independent correlative factors of the formation of intracranial aneurysm with irregular shape. The volume change rate and AR are independent correlative factors of the formation of intracranial aneurysm with irregular shape.

Modes of Berm and Beachface Recovery Following Storm Reset: Observations Using a Continuously Scanning Lidar

AbstractFollowing the rapid and destructive impacts of storm erosion, beach recovery is a key natural process of restoration, returning eroded sediment to the subaerial beach and rebuilding coastal morphology. While the effects of storm erosion have commonly been investigated, detailed studies into poststorm recovery are currently lacking. This study investigates wave‐driven recovery processes of the berm and beachface on a microtidal, swash‐aligned sandy beach. Following complete removal of the berm by a significant storm event, the entire 76‐day rebuilding of a swash berm is analyzed at the timescale of every semidiurnal tidal cycle, utilizing high‐resolution (5 Hz) swash and subaerial beach profile measurements from a continuously scanning fixed lidar. Tide‐by‐tide rates of subaerial volume change during berm recovery were most frequently observed between 1 and 2 m3/m/day, including losses and gains an order of magnitude larger than the more gradual rate of net gain (0.7 m3/m/day) observed for the entire recovery period. Patterns of berm crest formation and vertical growth were found to be primarily governed by the neap‐spring tide variations in total water levels. Tide‐by‐tide beachface and berm volume changes were used to classify four principal behavioral modes of subaerial profile variability during recovery. Using decision tree classification, modes were differentiated according to nearshore dimensionless fall velocity, swash exceedance of the berm crest, and ocean water levels. The findings provide novel behavioral and parametric insight into the tide‐by‐tide rebuilding of the beachface and berm by swash throughout a complete poststorm recovery period.

Compatibility of an elastomeric material with hydrazine propellant

In areospace industry, different kinds of elastomeric materials have been used in low-cost, light weight diaphragms and bladders in hydrazine propellant tanks. The compatibility of a new kind of vulcanized rubber compound 1803-1 with hydrazine propellant is studied experimentally, including immersion test, calalytic decomposition test and penetration test. The experiment process and test data are given about the permeation rate, mass change rate, volume change rate and other mechanical properties. The results show that most of the properties of material 1803-1 after compability test comply with the requirements of Chinese national standard. Rubber compound 1803-1 provides a reference when selecting the material for diaphragm tank bladders.

UAS based 3D shoreline change detection of Jupiter Inlet Lighthouse ONA after Hurricane Irma

ABSTRACTThe shoreline along the Jupiter Inlet Lighthouse Outstanding Natural Area (ONA) located in Jupiter, FL, USA, has been impacted by a variety of natural and anthropogenic factors over the years. This has resulted in significant erosion of the ONA’s shoreline, with an estimated retreat of up to 23 m over the last 50 years. Storm events, such as recent hurricanes Matthew (2016) and Irma (2017) contribute to the increase in the rate of shoreline retreat. The higher wind speed and storm surge affected the beach topography by transporting significant amounts of sand into the waterways and away from the site. The purpose of this research is to quantify the shoreline retreat at the Jupiter Inlet Lighthouse ONA caused by Hurricane Irma using Unmanned Aerial Systems (UAS)-based photogrammetry. The historical coastlines represented on aerial photography dating back to 1953 were used to analyse the rate of long-term change and isolate the impact due to Hurricane Irma. Short-term change rate of shoreline and volume change of beach topography was performed using transect-based spatial analysis of pre- and post-hurricane UAS data. The case study reveals that recent hurricane events increased the annual shoreline change rate to more than three times. Further, the volume of sand that has eroded due to Hurricane Irma was determined to be 2.8 hectares.

First principle study of occupancy, bonding characteristics and alloying effect of Zr, Nb, V in bulk <i>α</i>-Fe(C)

The volume change rate, total energy, binding characteristics, state density, charge distribution number and mechanical properties of cells formed by solid solution of Zr, Nb and V in α-Fe(C) are calculated by using the first-principles method. Thus, the effect of Zr, Nb, V on α-Fe(C) are studied in this paper. The results show that V displaces Fe atoms which is at the apex angle of α-Fe (C) cells preferentially, while Zr and Nb displace Fe atoms at the body center of α-Fe(C) cells. Zr and Nb reduce the stability of ferrite, but Zr is more difficult to solidly solubilize in α-Fe(C) than Nb. Solid solution of V increases the binding energy of crystal cells, meanwhile the toughness of crystal cell is mainly improved. After solid is solubilized in ferrite, Zr and Nb atoms only form metal bonds with Fe atoms while V and Fe atoms form the metal bonds and Fe—V ionic bonds. The ionic bonds of Fe—V are stronger than metal bonds of Zr and Nb atoms with Fe atoms, which is the main factor of the cell increasing. Zr and Nb mainly improve the mechanical properties of steel material by means of dispersion strengthening. To some extent, V solid solution can improve the toughness of ferrite, which is the main reason for improving the mechanical properties.

The Statistical Arbitrage Study of CSI 500 Stock Index Futures Based on Intraday Effect

Taking the CSI 500 stock index futures as the research object, the regression model of dummy variables of five indicators, including high-frequency return rate, volume change rate and near and far month contract price, was established. Then test whether these five indicators are affected by intraday effect and carry out statistical arbitrage based on intraday effect of spread. The empirical results show that the CSI 500 stock index futures have obvious intraday price fluctuations within 15 minutes of opening, and the intraday effect of the near-month contract is more significant than the far-month contract. The arbitrage strategy based on the intraday effect of spreading all the sample of both inside and outside can achieve higher success rate and yield, which is suitable for the short-term arbitrage. In actual trading, given the known probability of intraday profit, the intraday arbitrage method can provide reference for trading operation and risk aversion, so as to avoid losses caused by missed arbitrage opportunities.

Longitudinal tau-PET uptake and atrophy in atypical Alzheimer's disease.

The aims of this study were: to examine regional rates of change in tau-PET uptake and grey matter volume in atypical Alzheimer's disease (AD); to investigate the role of age in such changes; to describe multimodal regional relationships between tau accumulation and atrophy. Thirty atypical AD patients underwent baseline and one-year follow-up MRI, [18F]AV-1451 PET and PiB PET. Region- and voxel-level rates of tau accumulation and grey matter atrophy relative to cognitively unimpaired individuals, and the influence of age on such rates, were assessed. Univariate and multivariate analyses were performed between baseline measurements and rates of change, between baseline tau and atrophy, and between the two rates of change. Regional patterns of change in tau and volume differed, with highest rates of tau accumulation in frontal lobe and highest rates of atrophy in temporoparietal regions. Age had a negative effect on disease progression, predominantly on tau, with younger patients having a more rapid accumulation. Baseline tau uptake and regions of tau accumulation were disconnected, with high baseline tau uptake across the cortex correlated with high rates of tau accumulation in frontal and sensorimotor regions. In contrast, baseline volume and atrophy were locally related in the occipitoparietal regions. Higher tau uptake at baseline was locally related to higher rates of atrophy in frontal and occipital lobes. Tau accumulation rates positively correlated with rates of atrophy. In summary, our study showed that tau accumulation and atrophy presented different regional patterns in atypical AD, with tau spreading into the frontal lobes while atrophy remains in temporoparietal and occipital cortex, suggesting a temporal disconnect between protein deposition and neurodegeneration.

The Effect of Climate Change on Loss of Lake Volume: Case of Sedimentation in Central Rift Valley Basin, Ethiopia

Evaluating the impact of climate change on sediment yield has become one of the major topics in climate research. The purpose of this study was to investigate sediment yield contribution to lake volume change under changing climatic conditions in the Central Rift Valley Basin. The ensemble mean of five regional climate models (RCMs) in the coordinated regional climate downscaling experiment (CORDEX)-Africa was considered for the purpose of this study. The climate variables (precipitation, minimum and maximum temperatures) in RCMs were bias corrected against observed data (1985–2016) using linear scaling (LS), power transformation (PT), variance of scaling (VS), and quantile mapping (QM). Two emission scenarios, the Representative Concentration Pathways, RCP4.5 and RCP8.5, were considered for the future scenario period (2041–2070). Better results were obtained when the ensemble values of the bias correction methods were used. Hence, the projected values of climate variables after bias correction were used in the Soil and Water Assessment Tool (SWAT) hydrological model to estimate the sediment yield contribution to lake volume change due to climate change. The results show that the average projected precipitation will decrease by 7.97% and 2.55% under RCP4.5 and RCP8.5, respectively. On average, the maximum temperature will increase by 1.73 °C and 2.36 °C under RCP4.5 and RCP8.5, respectively, while the minimum temperature will increase by 2.16 °C and 3.07 °C under RCP4.5 and RCP8.5, respectively. The average annual sediment yield contributions to Lake Ziway were 431.05 ton/km2 and 322.82 ton/km2 for the Meki and Ketar rivers, respectively, in the historical period (1985–2010). The study also reveals that the annual sediment yield that was estimated for the Meki River was 323 ton/km2 and 382 ton/km2 under RCP4.5 and under RCP8.5, respectively. The sediment estimations for the Ketar River were 157 ton/km2 and 211 ton/km2 under RCP4.5 under RCP8.5, respectively. This will decrease the rate of volume change in Lake Ziway by 38% under RCP4.5 and by 23% under RCP8.5. The results show that the life expectancy of the lake is likely to increase under climate change scenarios. This will help water resources managers make informed decisions regarding the planning, management, and mitigation of the river basins.

Compaction of porous powder body consisting of the elastic­plastic medium

In the development of technological processes of producing cold-pressed sintered parts of low porosity, special attention is paid to the mechanism of density variation. In powder metallurgy, a multicomponent charge consisting of plastic metals, as well as poorly compressible inclusions and compounds, is often used. Such charge can equally be attributed to the charge consisting of iron powder, cast iron and glass. In this charge, the first component (base) is ductile iron, and the other two, cast iron and glass, are elastic components. It is of some interest what kind of compaction can be obtained in this case and what resulting equations can be used to estimate the mechanics of compaction of such a powder charge. The resulting equations of compaction of porous powder bodies of iron-cast iron-glass are proposed. The analysis of the isotropic, rigid-plastic hardening material such as iron-cast iron-glass is given. When compacting such a material, the rate of energy dissipation (pressing pressure) is determined by the rate of volume and form change of the body. It is shown that the difference between compressed (cast iron and glass) and plastic compacted (iron) materials forms special mechanical properties of the matrix. Consequently, hydrostatic pressure can affect the form change of the body, and shear stresses – volume change. The results of the mathematical approach to obtaining the resulting equations of compaction of the elastic-plastic medium showed the way to build a theory of plasticity of the compacted body, which eliminates the need to take into account the type of loading surface. When accounting the loading surface, it is impossible to obtain universal equations of compaction of the porous elastic-plastic medium. It is shown that to apply the classical formulation of the model of the elastic-plastic compacted body, it is necessary to assume that the loading surface is convex-closed

Evaluating Glacier Volume Changes since the Little Ice Age Maximum and Consequences for Stream Flow by Integrating Models of Glacier Flow and Hydrology in the Cordillera Blanca, Peruvian Andes

Evaluating the historical contribution of the volume loss of ice to stream flow based on reconstructed volume changes through the Little Ice Age (LIA) can be directly related to the understanding of glacier-hydrology in the current epoch of rapid glacier loss that has disquieting implications for a water resource in the Cordillera Blanca in the Peruvian Andes. However, the accurate prediction of the future glacial meltwater availability for the developing regional Andean society needs more extensive quantitative estimation from long-term glacial meltwater of reconstructed glacial volume. Modeling the LIA paleoglaciers through the mid-19th century (with the most extensive recent period of mountain glacier expansion having occurred around 1850 AD) in different catchments of the Cordillera Blanca allows us to reconstruct glacier volume and its change from likely combinations of climatic control variables and time. We computed the rate and magnitude of centennial-scale glacier volume changes for glacier surfaces between the LIA and the modern era, as defined by 2011 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model Version 2 (GDEM V2) and 2008 Light Detection and Range (LiDAR) data. The model simulation showed good agreement with the observed geomorphic data and the volume and surface area (V-S) scaling remained within the 25% error range in the reconstructed simulation. Also, we employed a recently demonstrated approach (Baraër, M. et al.) to calculate meltwater contribution to glacierized catchment runoff. The results revealed multiple peaks of both mean annual and dry season discharge that have never been shown in previous research on the same mountain range.

Increasing Silicone Oil Viscosity Increases Resistance to Volume Displacement in an in vitro Retinal Detachment Model

Purpose: To determine whether higher-viscosity silicone oils offer greater resistance to volume displacement in an in vitro eye model of retinal detachment and could subsequently be expected to generate stronger retinal tamponades in cases of recurrent or complex retinal detachments. Methods: We used an eye model that included a membrane representing the retina. Silicone oils with different viscosities were injected, and oil displacement and resistance were measured. Results: Membrane movement and volume changes in an eye model were proportional to the viscosity of the oil: the lower the viscosity, the faster volume changes and displacement occurred. Conclusions: Our results show that the volume change rate has a linear relationship with oil viscosity. Our findings suggest that in this eye model, silicone oil tamponades the retina against the retinal pigment epithelium mainly through volume displacement and that silicone oil viscosity may play an important role in preventing retinal displacement and in providing tamponade.

Predictive Value of Texture Analysis in the Treatment of Magnetic Resonance-guided Focused Ultrasound Surgery for Symptomatic Uterine Fibroids

Objective To evaluate the predictive value of texture analysis in the treatment of magnetic resonance-guided focused ultrasound surgery(MRgFUS)for symptomatic uterine fibroids.Methods Totally 16 patients with symptomatic uterine fibroids who accepted MRgFUS in Peking Union Medical College Hospital from April 2010 to January 2013 were included. Enhanced magnetic resonance imaging(MRI)was performed before treatment,immediately after treatment,and during the 12-month follow-up. The TexRAD software was used to measure the texture parameters of the fibroids in T2WI sagittal images,and the texture indicators including means and standard deviations(SD),entropy,mean of positive pixels(MPP),skewness,and kurtosis were collected. The fibroid's volume and their change rates were calculated by measuring the relevant diameter of the target fibroid. The Uterine Fibroid Symptoms and Quality of Life(UFS-QOL)was used to calculate the symptom severity scores(SSS)and its change rate. The statistical difference of parameters among the groups was analyzed. The correlations between each texture parameter and the therapeutic outcome of the fibroids were analyzed respectively.Results The average volume for fibroids before treatment was(96.5±84.9)cm 3,which was reduced to(55.1±71.0)cm 3 after treatment for 12 months,and the volume change rate(εV%)was(49±20)%. The standardized SSS score before treatment was(34.18±15.29)scores,decreased to(17.78±11.84)scores 12 months after treatment,with a change rate of(45±32)%,and the non-perfused volume ratio(NPV%)was(62±20)%. There were significant differences among the parameters mean,SD,entropy,and MPP among three groups(all P<0.05),and the changes of them were regular,all of which showed a significant decrease immediately after treatment and a significant increase 12 months after treatment,and the increase degree was higher than the preoperative level. SD(SSF2:r=0.503,P=0.047;SSF4:r=0.529,P=0.035;SSF6:r=0.519,P=0.039)and entropy(SSF2:r=0.527,P=0.036;SSF4:r=0.517,P=0.040;SSF6:r=0.495,P=0.050)of the after-treatment group moderately associated with the εV%. Entropy of the before-treatment group was moderately associated with NPV%(SSF2:r=0.507,P=0.045;SSF4:r=0.543,P=0.030;SSF6:r=0.548,P=0.028).Conclusion There is a certain correlation between the changes of MRI texture parameters before and after treatment and the effect of MRgFUS in the treatment of uterine fibroids,and texture analysis may have certain value in the predicting the effect of MRgFUS on uterine fibroids.

Tumor Volume Changes During and after Radiation Therapy as a Predictor for Local Recurrence in Locally Advanced Non-Small Cell Lung Cancer

Prediction of tumor response during the treatment course may allow for individualized adaptive radiotherapy. We hypothesized that primary tumor volume change during and immediately following radiation therapy is predictive of local recurrence, thus providing information on which patients may benefit from treatment adaptation. Forty-one patients with locally advanced non-small cell lung cancer (Stage III = 38, Stage II = 3) were treated with definitive radiotherapy using conventional fractions of 1.8 or 2 Gy. Doses ranged from 54 to 70 Gy with a median dose of 66 Gy. All patients were previously enrolled on imaging protocols and underwent multiple 4D fan beam CT scans during radiotherapy. Thirty-six patients also received chemotherapy (29 concurrent, 5 sequential). The primary tumor was contoured on fan beam CT scans acquired pre-treatment, during treatment, and up to 3 months following treatment. A competing risk model was used to determine if there was a relationship between the primary tumor recurrence and percent reduction in tumor size per day. The median overall survival for all patients was 1.74 years. The median follow-up time for living patients was 6.45 years (range: 3.41 to 6.96 years). Median initial primary tumor size was 75.7cc (range: 4.7cc to 622.0cc). Twenty patients (49%) had LR at the primary tumor site, and 23 patients (56%) had distant metastases. During radiotherapy, the average percent reduction of tumor per day was 1.34% (range: -0.25% to 2.72%). Tumors that decreased in size less than 1.4% a day had a hazard ratio of 2.15 for local recurrence compared to those that decreased in size more than 1.4% a day (p = 0.0075). Although larger initial tumor size was associated with an increased risk of primary tumor recurrence (p = 0.0064), there was no relationship between initial tumor size and daily percentage change in tumor size (Pearson correlation coefficient of -0.29). The change in tumor size was not associated with the rates of distant metastases (p = 0.45). Scans taken at 3 months follow-up were also analyzed as tumors continued to shrink in size after treatment, albeit slower at an average rate of 0.81% per day (range: 0.08% to 1.28%). The average volume at 3 months was 21.5cc (range: 0.53cc to 188.3cc). There was no relationship between the change in tumor size at 3 months following treatment and local control (p = 0.18). An increased rate of tumor volume change is associated with a significantly lower rate of primary tumor recurrence and may provide an efficient and easily accessible early measure of radiation response.

Utility of 18F-Fluorocholine (FCH) PET/CT to Optimize Treatment Strategy and Radiation Therapy (RT) Planning in Patients with Biochemical Recurrence (BCR) of Prostate Cancer (PCa)

RT is a main component in PCa therapy. After radical prostatectomy (RP), a rising PSA indicates PCa recurrence that may be cured with salvage radiotherapy (SRT). To maximize chances for cure, irradiated volumes should completely encompass the extent of disease. Thus, accurate estimation of disease extension is critical for RT planning in salvage setting. Integration of Positron Emission Tomography (PET) into routine evaluation of PCa patients (pts) may improve both staging accuracy and RT planning. 18F-fluorodeoxyglucose PET/CT is routinely used in radiation planning for several cancers. Additional PET probes, such as FCH, appear to be sensitive and specific in PCa. The objective of this study is to: (i) map the recurrence pattern of early BCR after RP, using FCH-PET/CT; (ii) determine how often volume definition decided prior PET/CT had to be modified to include pelvic and extra-pelvic diseases; (iii) assess the potential impact of FCH-PET/CT on SRT dose modification delivered to the site of recurrence. This study included 51 pts between 2011 and 2016. Median age was 62 (50-77) years. RP used robotic technology in 32 (62%) pts. All patients underwent FCH-PET/CT in a single institution before SRT at the time of BCR with PSA levels >/=0.16 ng/ml. Indications and RT volumes were systematically discussed in the multidisciplinary board meeting. The first definition of the CTV included either the prostate bed (PB) alone or PB + pelvic lymph nodes contoured on the simulation CT-scan dataset by a radiation oncologist blinded to the PET/CT results. PET/CT images were analyzed jointly by a nuclear medicine physician and radiation oncologist. FCH-positive lesions not covered by planning volumes based on the blinded CTV were considered to have a major potential impact on treatment planning. After RP, 9 (17%) pts had T3, Gleason >7 or N+. Median PSA at time of FCH-PET/CT was 1.4 (0.16-37) ng/mL. 19 of 51 (37%) pts had a positive FCH-PET/CT at BCR. The detection rate of FCH uptake was significantly higher in pts with PSA≥0.5ng/mL than in those with PSA <0.5ng/mL (p<0.008). Among the 19 pts with positive FCH-PET/CT, 9 (47%) had at least one metastatic site not covered by the blinded CTV, 6 (31%) had extra-pelvic lesions while 5 (26%) had FCH-positive lesions within the pelvis but not covered by the blinded CTV. The two most common FCH-positive lesion locations outside the blinded CTV were bone (26%) and perirectal lymph nodes (37%). The rate of total RT volume changes was 13/19 (68%). Finally, 2 (10.5%) pts had PB uptake that needed an increased SRT dose up to 70Gy. We confirm that FCH-PET/CT can allow better lesions mapping at the time of BCR. At least one-third of the patients had positive FCH-PET/CT with a trend of significance after a PSA level of 0.5ng/mL. When metastatic disease is detected, FCH uptake changed SRT planning in more than 2/3 of patients. Further investigations and longer follow-up are needed to assess the impact of these changes on outcome.

Pretreatment Texture Analysis of Routine Magnetic Resonance Images and Shape Analysis of the Diffusion Tensor Predict Volumetric Response after Radiosurgery for Meningiomas

Tumor progression after stereotactic radiosurgery remains a major complication in WHO grade I meningiomas, with figures reported between 5-10%. According to our previous study, Diffusion Tensor Imaging (DTI) parameters can differentiate between meningioma subtypes and predict the reduction in volume of meningiomas after SRS. However DTI is still not frequently performed for SRS. The objective of this study was to identify those parameters from routine T1- and T2-weigted Magnetic Resonance (MR) sequences, and as well as from DTI, which predict best volume changes of meningiomas after Gamma Knife Radio-Surgery (GKRS) treatment. In 32 patients (mean age 58y) with meningiomas (mean volume 8.80cm3, mean dose 14.2Gy), routine 3 Tesla MR images as well as 11 different DTI parameter maps, including skewness of tensor shape, were measured before SRS. A total of 104 parameters derived from first level texture analysis of the pre-treatment MR images, including calculation of mean, standard deviation, 2.5 and 97.5 percentiles, kurtosis and skewness of data histograms on a voxel-wise basis, were correlated with lesion volume change after a mean follow up period of 3 years (19.5 – 63.3 months). Mean volume change rate per month after SRS was 0.92%. 1 (3%) meningioma progressed, 5 (16%) meningiomas stayed stable and 26 (81%) regressed. Several DTI-derived parameters correlated significantly with meningioma volume change. The parameter to predict best response of SRS was the 2.5 percentile value of the planar spherical index of the diffusion tensor (correlation coefficient -0.682, p≤0.001), whereas from the non-DTI parameters, only standard deviation of T2-weighted data correlated significantly with tumor volume change (correlation coefficient 0.505, p≤0.05). Other factors, like original tumor size, prescription dose and patient’s age, did not present significant correlation. WHO grade I Meningiomas differ in tissue homogeneity and in radiosensitivity. DTI-derived parameters show a higher correlation to shrinkage of meningioma volume after SRS than data from T1- and T2-weigted sequences. Combinations of standard deviation of T2 and DTI parameters can further improve correlation. If only routine MR images are available, standard deviation of T2-weighted images may be considered to predict volumetric response of meningiomas after SRS.

ANALYSIS OF WORK EFFICIENCY IN HARD COAL MINING IN POLAND

Motivation: This article presents the analysis of work efficiency in hard coal mining in Poland. Labour costs in Polish mining enterprises account for over 40% of the total production cost. For this reason, the labour productivity of employees has a key impact on the final operating profit.Problem statement: In the case of Polish coal companies, the efficiency is the index value of which particular restructuration programs have attempted to increase for years. However, because of the effect of overstaffing and a decrease in hard coal exploitation, the task was impossible.Approach and results: In this article the effects of the latest recovery programme have been presented, the production efficiency index has been determined; the rate of changes in production volume has been presented as well as the employment figure and the average salary in the Polish mining industry in the recent decade. Moreover, the prognosis of the employment figure using the ARIMA and ARMAX class model was conducted.Conclusions: It should be noted that in the last four years a significant reduction in the employment figure has been onserved in the hard coal mining industry. This figure has been adjusted to the production volume level. This, in turn, has positively influenced the work efficiency coefficient level.

Relationship between upper airway volume and polysomnography parameters of patients with obstructive sleep apnea hypopnea syndrome

Objective:To study the relationship among upper airway volume of naso-pharyngeal, yelo-pharyngeal,glosso-pharyngeal, hypo-pharyngeal area which measured by spiral computed tomography three-dimensional reconstruction technique, apnea hypopnea indexes, and the lowest oxygen saturation in patients with OSAHS.Method:①fifty-one patients with OSAHS were received polysomnography, and then were divided into groups by the AHI,LSaO₂ values. ②To measure upper airway volume at normal breath and Müller maneuver state using spiral computed tomography three-dimensional reconstruction technique of CT measurement, and to calculate volume change rate and observe the upper airway compliance. ③To analyses the relationship between upper airway volume and AHI,LSaO₂ values.Result:The smallest upper airway volume of OSAHS was at the velo-pharyngeal level; the volume of velo-pharyngeal level were negatively correlated with AHI during normal respiration and Müller's maneuver state and were positively correlated with LSaO₂; the volume of hypo-pharyngeal were negatively correlated with AHI during normal respiration; the volume of glosso-pharyngeal were positively correlated with LSaO₂ during Müller's maneuver state.Conclusion:①The volume of velo-pharyngeal level with OSAHS patients can reflect the severity of AHI,LSaO₂. ②The measurement of upper airway volume using spiral computed tomography three-dimensional reconstruction technique is good method to evaluate the upper airway compliance of OSAHS patients.