bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium-Modulating Cyclophilin Ligand Is Essential for the Survival of Activated T Cells and for Adaptive Immunity
Authors: Chan Siaw-Li , Lindquist Lonn D. , Hansen Michael J. , Girtman Megan A. , Pease Larry R. , Bram Richard J.
Published: November 2015

Calcium-modulating cyclophilin ligand (CAML) is an endoplasmic reticulum resident protein that is widely expressed. Although it has been demonstrated to participate in the tail-anchored protein insertion pathway, its physiological role in the mature immune system is unknown. In this work, we show that mature, peripheral T cells require CAML for survival specifically following TCR-induced activation. In this study, we examined mature T cells from spleen and lymph nodes of tamoxifen-inducible CAML knockout mice (tCAML−/−). Whereas CAML-deficient T cells were able to express the early activation markers CD25 and CD69, and produce IL-2 normally upon stimulation, deficient cells proliferated less and died. Cells did not require CAML for entry into the S phase of the cell cycle, thus implicating its survival function at a relatively late step in the T cell activation sequence. In addition, CAML was required for homeostatic proliferation and for Ag-dependent cell killing in vivo. These results demonstrate that CAML critically supports T cell survival and cell division downstream of T cell activation.
Traumatic brain injury and the post-concussion syndrome: A diffusion tensor tractography study
Authors: D'Souza Maria M , Trivedi Richa , Singh Kavita , Grover Hemal , Choudhury Ajay , Kaur Prabhjot , Kumar Pawan , Tripathi Rajendra Prashad
Published: November 2015

Aim: The aim of the present study is to evaluate diffusion tensor tractography (DTT) as a tool for detecting diffuse axonal injury in patients of acute, mild, and moderate traumatic brain injury (TBI), using two diffusion variables: Fractional anisotropy (FA) and mean diffusivity (MD). The correlation of these indices with the severity of post-concussive symptoms was also assessed. Materials and Methods: Nineteen patients with acute, mild, or moderate TBI and twelve age- and sex-matched healthy controls were recruited. Following Magnetic Resonance Imaging (MRI) on a 3.0-T scanner, DTT was performed using the 'fiber assignment by continuous tracking' (FACT) algorithm for fiber reconstruction. Appropriate statistical tools were used to see the difference in FA and MD values between the control and patient groups. In the latter group, the severity of post-concussive symptoms was assessed six months following trauma, using the Rivermead Postconcussion Symptoms Questionnaire (RPSQ). Results: The patients displayed significant reduction in FA compared to the controls (P < 0.05) in several tracts, notably the corpus callosum, fornix, bilateral uncinate fasciculus, and bilateral superior thalamic radiations. Changes in MD were statistically significant in the left uncinate, inferior longitudinal fasciculus, and left posterior thalamic radiation. A strong correlation between these indices and the RPSQ scores was observed in several white matter tracts. Conclusion: Diffusion tensor imaging (DTI)-based quantitative analysis in acute, mild, and moderate TBI can identify axonal injury neuropathology, over and above that visualized on conventional MRI scans. Furthermore, the significant correlation observed between FA and MD indices and the severity of post-concussive symptoms could make it a useful predictor of the long-term outcome.
Clinical outcomes of endovascularly managed iatrogenic renal hemorrhages
Authors: Chiramel George Koshy , Keshava Shyamkumar Nidugala , Moses Vinu , Kekre Nitin , Tamilarasi V , Devasia Anthony
Published: November 2015

Objective: To evaluate the effectiveness of endovascular management in iatrogenic renal injuries with regard to clinical status on follow-up and requirements for repeat angiography and embolization. Materials and Methods: This retrospective study included patients who were referred for endovascular management of significant hemorrhage following an iatrogenic injury. Data was recorded from the Picture Archiving and Communication system (PACS) and electronic medical records. The site and type of iatrogenic injury, imaging findings, treatment, angiography findings, embolization performed, clinical status on follow-up, and requirement for repeat embolization were recorded. The outcomes were clinical resolution, nephrectomy, or death. Clinical findings were recorded on follow-up visits to the clinic. Statistical analysis was performed using descriptive statistics. Results: Seventy patients were included in this study between January 2000 and June 2012. A bleeding lesion (a pseudoaneurysm or arteriovenous fistula) was detected during the first angiogram in 55 patients (78.6%) and was selectively embolized. Fifteen required a second angiography as there was no clinical improvement and five required a third angiography. Overall, 66 patients (94.3%) showed complete resolution and 4 patients (5.7%) died. Three patients (4.3%) underwent nephrectomy for clinical stabilization even after embolization. There were no major complications. The two minor complications resolved spontaneously. Conclusions: Angiography and embolization is the treatment of choice in iatrogenic renal hemorrhage. Upto 20% of initial angiograms may not reveal the bleed and repeat angiography is required to identify a recurrent or unidentified bleed. The presence of multiple punctate bleeders on angiography suggests an enlarging subcapsular hematoma and requires preoperative embolization and nephrectomy.
Diagnostic value of diffusion tensor imaging derived metrics as biomarkers of cerebral changes in developmental delay
Authors: Verma Ashish , Sagar Narendra C , Kumar Ashok , Srivastava Arvind
Published: November 2015

Context: Children with developmental delay (DD) can be rehabilitated if an early diagnosis and intervention is done. A negative magnetic resonance imaging (MRI) study utilizing routine sequences makes it difficult for the clinician to convince the family toward a long-term rehabilitation schedule. Diffusion tensor imaging (DTI) can demonstrate deranged myelination in developmentally delayed children having normal routine MRI. Aim: To evaluate the role of DTI-derived metrics for assessment of deranged myelination in developmentally delayed children having normal routine MRI. Study Setting and Design: Prospective case control observational study conducted over a cross-section of referrals at a university-based teaching institute over a period of 2 years. Patients and Methods: Fifty cases of DD and 15 age-sex matched controls (age group of 2-12 years) were included from those presenting voluntarily to the pediatric out-patient services. Routine MRI and DTI were performed in both the groups following a standard protocol. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated in certain pre-defined regions. Statistical Analysis: Central tendency was measured for each of the metrics using mean. Inter- and intra-group comparisons were performed using t-test.
Results: Twenty-three regions of interest with 46 variables were included in the final analysis. Nineteen (82.60%) regions of interest showed at least one statistically significant variable, while 24 out of 46 (54.34%) variables showed statistical significance for future consideration. The important regions to be evaluated in a case of DD are the corpus callosum, bilateral forceps minor and forceps major, bilateral parietal lobes, bilateral post-central gyrus, and bilateral posterior limb internal capsule (PLIC). The regions which did not show any significance are bilateral pars triangularis and right frontal lobe. Other regions remained indeterminate and need further evaluation. Conclusion: DTI demonstrates myelination abnormality in children with DD, having a normal routine MRI.
Evaluation of breast parenchymal density with QUANTRA software
Authors: Pahwa Shivani , Hari Smriti , Thulkar Sanjay , Angraal Suveen
Published: November 2015

Purpose: To evaluate breast parenchymal density using QUANTRA software and to correlate numerical breast density values obtained from QUANTRA with ACR BI-RADS breast density categories. Materials and Methods: Two-view digital mammograms of 545 consecutive women (mean age - 47.7 years) were categorized visually by three independent radiologists into one of the four ACR BI-RADS categories (D1-D4). Numerical breast density values as obtained by QUANTRA software were then used to establish the cutoff values for each category using receiver operator characteristic (ROC) analysis. Results: Numerical breast density values obtained by QUANTRA (range - 7-42%) were systematically lower than visual estimates. QUANTRA breast density value of less than 14.5% could accurately differentiate category D1 from the categories D2, D3, and D4 [area under curve (AUC) on ROC analysis - 94.09%, sensitivity - 85.71%, specificity - 84.21%]. QUANTRA density values of <19.5% accurately differentiated categories D1 and D2 from D3 and D4 (AUC - 94.4%, sensitivity - 87.50%, specificity - 84.60%); QUANTRA density values of <26.5% accurately differentiated categories D1, D2, and D3 from category D4 (AUC - 90.75%, sensitivity - 88.89%, specificity - 88.621%).
Conclusions: Breast density values obtained by QUANTRA software can be used to obtain objective cutoff values for each ACR BI-RADS breast density category. Although the numerical density values obtained by QUANTRA are lower than visual estimates, they correlate well with the BI-RADS breast density categories assigned visually to the mammograms.
Endovascular treatment of central venous obstruction as a complication of prolonged hemodialysis – Preliminary experience in a tertiary care center
Authors: Yadav Mukesh K , Sharma Madhurima , Lal Anupam , Gupta Vivek , Sharma Ashish , Khandelwal Niranjan
Published: November 2015

Background: Central venous disease is a serious complication in patients undergoing hemodialysis, often presenting with symptoms of venous hypertension. Treatment is aimed to provide symptomatic relief and to maintain hemodialysis access site patency. Aim: To describe our initial experience in the endovascular treatment of central venous stenosis or obstruction in patients undergoing hemodialysis. Settings and Design: This was a retrospective study carried out in a tertiary care center. Study duration was 24 months. Follow-up was variable. Materials and Methods: Eleven patients of chronic renal failure undergoing hemodialysis presented with central vein stenosis or obstruction having ipsilateral vascular access, between July 2012 and July 2014. All the patients underwent endovascular treatment and were analyzed retrospectively. Results and Conclusion: A total of 11 patients (4 male and 7 female) underwent 18 interventions for 13 stenotic segments during a time period of 2 years. Eight stenotic segments were in brachiocephalic vein, three in subclavian vein, and two in axillary veins. The technical success rate for endovascular treatment was 81.8%. Two patients underwent percutaneous transluminal angioplasty (PTA) alone and presented with restenosis later. Balloon angioplasty followed by stenting was done in seven patients, two of which required reintervention during follow-up. We found endovascular treatment safe and effective in treating central venous disease.
Problems and preferences in pediatric imaging
Authors: Thukral Brij Bhushan
Published: November 2015

Radiological imaging is extremely valuable as a diagnostic tool in the pediatric population, but it comes with a number of distinct challenges as compared to the imaging of adults. This is because of the following: It requires dedicated imaging protocols to acquire the images, there is need for sedation or general anesthesia for longer procedures such as MRI, specific training is required for the healthcare personnel involved, thorough knowledge and expertise should be applied for evaluating the images, and most importantly, it requires consideration for radiation exposure if ionizing radiation is being used. One of the challenges for clinical care personnel is to gain the child's trust and co-operation before and throughout the duration of an examination, which can prove to be difficult in children who may be ill and have pain. This is important to acquire quality images and prevent repeat examinations. Even with a quality examination, the accurate interpretation of images requires a thorough knowledge of the intricate and dynamic face of anatomy and specific pathological presentations in children. The increased radiation sensitivity of growing organs and children's longer expected life spans make them more susceptible to the harmful effects of radiation. Imaging pediatric patients in a dedicated pediatric imaging department with dedicated pediatric CT technologists may result in greater compliance with pediatric protocols and significantly reduced patient dose. In order to prevent the harmful effects of ionizing radiation, As Low As Reasonably Achievable (ALARA) principle should be strictly followed. This article seeks to draw attention to various challenges of pediatric imaging and the ways to overcome them.
Emerging clinical applications of PET based molecular imaging in oncology: the promising future potential for evolving personalized cancer care
Authors: Dhingra Vandana K , Mahajan Abhishek , Basu Sandip
Published: November 2015

This review focuses on the potential of advanced applications of functional molecular imaging in assessing tumor biology and cellular characteristics with emphasis on positron emission tomography (PET) applications with both 18-fluorodeoxyglucose (FDG) and non-FDG tracers. The inherent heterogeneity of cancer cells with their varied cellular biology and metabolic and receptor phenotypic expression in each individual patient and also intra-and inter-lesionally in the same individual mandates for transitioning from a generalized "same-size-fits-all" approach to personalized medicine in oncology. The past two decades have witnessed improvement of oncological imaging through CT, MR imaging, PET, subsequent movement through hybrid or fusion imaging with PET/CT and single-photon emission computerized tomography (SPECT-CT), and now toward the evolving PET/MR imaging. These recent developments have proven invaluable in enhancing oncology care and have the potential to help image the tumor biology at the cellular level, followed by providing a tailored treatment. Molecular imaging, integrated diagnostics or Radiomics, biology-driven interventional radiology and theranostics, all hold immense potential to serve as a guide to give "start and stop" treatment for a patient on an individual basis. This will likely have substantial impact on both treatment costs and outcomes. In this review, we bring forth the current trends in molecular imaging with established techniques (PET/CT), with particular emphasis on newer molecules (such as amino acid metabolism and hypoxia imaging, somatostatin receptor based imaging, and hormone receptor imaging) and further potential for FDG. An introductory discussion on the novel hybrid imaging techniques such as PET/MR is also made to understand the futuristic trends.
OSBP-Related Protein Family in Lipid Transport over Membrane Contact Sites
Authors: Olkkonen Vesa M.
Published: November 2015

Increasing evidence suggests that oxysterol-binding protein-related proteins (ORPs) localize at membrane contact sites, which are high-capacity platforms for inter-organelle exchange of small molecules and information. ORPs can simultaneously associate with the two apposed membranes and transfer lipids across the interbilayer gap. Oxysterol-binding protein moves cholesterol from the endoplasmic reticulum to trans-Golgi, driven by the retrograde transport of phosphatidylinositol-4-phosphate (PI4P). Analogously, yeast Osh6p mediates the transport of phosphatidylserine from the endoplasmic reticulum to the plasma membrane in exchange for PI4P, and ORP5 and -8 are suggested to execute similar functions in mammalian cells. ORPs may share the capacity to bind PI4P within their ligand-binding domain, prompting the hypothesis that bidirectional transport of a phosphoinositide and another lipid may be a common theme among the protein family. This model, however, needs more experimental support and does not exclude a function of ORPs in lipid signaling.
Toward enhanced capability for detecting and predicting dust events in the western United States: the Arizona case study
Authors: Huang M. , Tong D. , Lee P. , Pan L. , Tang Y. , Stajner I. , Pierce R. B. , McQueen J. , Wang J.
Published: November 2015

Abstract. Dust aerosols affect human life, ecosystems, atmospheric chemistry and climate in various aspects. Some studies have revealed intensified dust activity in the western US during the past decades despite the weaker dust activity in non-US regions. It is important to extend the historical dust records, to better understand their temporal changes, and to use such information to improve the daily dust forecasting skill as well as the projection of future dust activity under the changing climate. This study develops dust records in Arizona in 2005–2013 using multiple observation data sets, including in situ measurements at the surface Air Quality System (AQS) and Interagency Monitoring of Protected Visual Environments (IMPROVE) sites, and level 2 deep blue aerosol product by the Moderate Resolution Imaging Spectroradiometer. The diurnal and inter-annual variability of identified dust events are shown related to observed weather patterns (e.g., wind and soil moisture) and surface conditions (e.g., land cover type and vegetation conditions), suggesting a potential for use of satellite soil moisture and land products to help interpret and predict dust activity. Backtrajectories computed using NOAA's Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicate that the Sonoran and Chihuahuan deserts are important dust source regions during identified dust events in Phoenix, Arizona. Finally, we assess the impact of a recent strong dust event on western US air quality, using various observational and modeling data sets, during a period with a stratospheric ozone intrusion event. The capability of the current US National Air Quality Forecasting Capability (NAQFC) Community Multi-scale Air Quality (CMAQ) modeling system to represent the magnitude and the temporal variability of aerosol concentrations is evaluated for this event. Directions for integrating observations to further improve dust emission modeling in CMAQ are also suggested.
Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows
Authors: Han J. , Shin B. , Lee M. , Hwang G. , Kim J. , Shim J. , Lee G. , Shim C.
Published: November 2015

Abstract. Ieodo Ocean Research Station (IORS), a research tower (~ 40 m a.s.l.) for atmospheric and oceanographic observations, is located in the East China Sea (32.07° N, 125.10° E). The IORS is almost equidistant from South Korea, China, and Japan and, therefore, it is an ideal place to observe Asian outflows without local emission effects. The seasonal variation of ozone was distinct, with a minimum in August (37 ppbv) and two peaks in April and October (62 ppbv), and was largely affected by the seasonal wind pattern over east Asia. At IORS, six types of air masses were distinguished with different levels of O3 concentrations by the cluster analysis of backward trajectories. Marine air masses from the Pacific Ocean represent a relatively clean background air with a lowest ozone level of 32 ppbv, which was most frequently observed in summer (July–August). In spring (March–April) and winter (December–February), the influence of Chinese outflows was dominant with higher ozone concentrations of 62 and 49 ppbv, respectively. This study confirms that the influence of Chinese outflows was the main factor determining O3 levels at IORS and its extent was dependent on meteorological state, particularly at a long-term scale.
Estimates of free-tropospheric NO2 and HCHO mixing ratios derived from high-altitude mountain MAX-DOAS observations in the mid-latitudes and tropics
Authors: Schreier S. F. , Richter A. , Wittrock F. , Burrows J. P.
Published: November 2015

Abstract. In this study, mixing ratios of NO2 (XNO2) and HCHO (XHCHO) in the free troposphere are derived from two Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) data sets collected at Zugspitze (2650 m a.s.l., Germany) and Pico Espejo (4765 m a.s.l., Venezuela). The estimation of NO2 and HCHO mixing ratios is based on the modified geometrical approach, which assumes a single-scattering geometry and a scattering point altitude close to the instrument. Firstly, the horizontal optical path length (hOPL) is obtained from O4 differential slant column densities (DSCDs) in the horizontal (0°) and vertical (90°) viewing directions. Secondly, XNO2 and XHCHO are estimated from the NO2 and HCHO DSCDs at the 0 and 90° viewing directions and averaged along the obtained hOPLs. As the MAX-DOAS instrument was performing measurements in the ultraviolet region, wavelength ranges of 346–372 and 338–357 nm are selected for the DOAS analysis to retrieve NO2 and HCHO DSCDs, respectively. In order to compare the measured O4 DSCDs and moreover to perform some sensitivity tests, the radiative transfer model SCIATRAN with adapted altitude settings for mountainous terrain is operated to simulate synthetic spectra, on which the DOAS analysis is also applied. The overall agreement between measured and synthetic O4 DSCDs is better for the higher Pico Espejo station than for Zugspitze. Further sensitivity analysis shows that a change in surface albedo (from 0.05 to 0.7) can influence the O4 DSCDs, with a larger absolute difference observed for the horizontal viewing direction. Consequently, the hOPL can vary by about 5 % throughout the season, for example when winter snow cover fully disappears in summer. Typical values of hOPLs during clear sky conditions are 19 km (14 km) at Zugspitze and 34 km (26.5 km) at Pico Espejo when using the 346–372 nm (338–357 nm) fitting window. The estimated monthly values of XNO2 (XHCHO), averaged over these hOPLs during clear sky conditions, are in the range of 60–100 ppt (500–950 ppt) at Zugspitze and 8.5–15.5 ppt (255–385 ppt) at Pico Espejo. Interestingly, multi-year averaged monthly means of XNO2 and XHCHO increase towards the end of the dry season at the Pico Espejo site, suggesting that both trace gases are frequently lifted above the boundary layer as a result of South American biomass burning.
An approximation for homogeneous freezing temperature of water droplets
Authors: O K.-T. , Wood R.
Published: November 2015

Abstract. In this work, based on the well-known formulae of classical nucleation theory (CNT), the temperature TNc = 1 at which the mean number of critical embryos inside a droplet is unity is derived and proposed as a new approximation for homogeneous freezing temperature of water droplets. Without consideration of time dependence and stochastic nature of the ice nucleation process, the approximation TNc = 1 is able to reproduce the dependence of homogeneous freezing temperature on drop size and water activity of aqueous drops observed in a wide range of experimental studies. We use the TNc = 1 approximation to argue that the distribution of homogeneous freezing temperatures observed in the experiments may largely be explained by the spread in the size distribution of droplets used in the particular experiment. It thus appears that this approximation is useful for predicting homogeneous freezing temperatures of water droplets in the atmosphere.
Reviews and syntheses: the first records of deep-sea fauna – a correction and discussion
Authors: Etter W. , Hess H.
Published: November 2015

Abstract. The soundings in deep waters of Baffin Bay, together with the recovery of a basket star by John Ross in 1818, was a milestone in the history of deep-sea research. Although the alleged water depths of up to 1950 m were by far not reached, these were nevertheless the first soundings in deep bathyal (to perhaps uppermost abyssal) depths. Furthermore, the recovery of a benthic animal proved that animal life existed at great depths. Yet this was not the first published record of deep-sea fauna as it is often portrayed. This merit goes to accidental catches of the stalked crinoid Cenocrinus asterius that were recovered with fishing lines from upper bathyal environments near Antillean islands. In addition, the description of several deep-sea fishes considerably predated the John Ross episode.
Stratification of surface waters during the last glacial millennial climatic events: a key factor in subsurface and deep-water mass dynamics
Authors: Wary M. , Eynaud F. , Sabine M. , Zaragosi S. , Rossignol L. , Malaizé B. , Palis E. , Zumaque J. , Caulle C. , Penaud A. , Michel E. , Charlier K.
Published: November 2015

Abstract. The last glacial period was punctuated by abrupt climatic events with extrema known as Heinrich and Dansgaard–Oeschger events. These millennial events have been the subject of many paleoreconstructions and model experiments in the past decades, but yet the hydrological processes involved remain elusive. In the present work, high-resolution analyses were conducted on the 12–42 ka BP section of core MD99-2281 retrieved southwest of the Faeroe Islands, and combined with analyses conducted in two previous studies (Zumaque et al., 2012; Caulle et al., 2013). Such a multiproxy approach, coupling micropaleontological, geochemical and sedimentological analyses, allows us to track surface, subsurface, and deep hydrological processes occurring during these rapid climatic changes. Records indicate that the coldest episodes of the studied period (Greenland stadials and Heinrich stadials) were characterized by a strong stratification of surface waters. This surface stratification seems to have played a key role in the dynamics of subsurface and deep-water masses. Indeed, periods of high surface stratification are marked by a coupling of subsurface and deep circulations which sharply weaken at the beginning of stadials, while surface conditions progressively deteriorate throughout these cold episodes; conversely, periods of decreasing surface stratification (Greenland interstadials) are characterized by a coupling of surface and deep hydrological processes, with progressively milder surface conditions and gradual intensification of the deep circulation, while the vigor of the subsurface northward Atlantic flow remains constantly high. Our results also reveal different and atypical hydrological signatures during Heinrich stadials (HSs): while HS1 and HS4 exhibit a "usual" scheme with reduced overturning circulation, a relatively active North Atlantic circulation seems to have prevailed during HS2, and HS3 seems to have experienced a re-intensification of this circulation during the middle of the event. Our findings thus bring valuable information to better understand hydrological processes occurring in a key area during the abrupt climatic shifts of the last glacial period.
A conceptual, distributed snow redistribution model
Authors: Frey S. , Holzmann H.
Published: November 2015

Abstract. When applying conceptual hydrological models using a temperature index approach for snowmelt to high alpine areas often accumulation of snow during several years can be observed. Some of the reasons why these "snow towers" do not exist in nature are vertical and lateral transport processes. While snow transport models have been developed using grid cell sizes of tens to hundreds of square metres and have been applied in several catchments, no model exists using coarser cell sizes of 1 km2, which is a common resolution for meso- and large-scale hydrologic modelling (hundreds to thousands of square kilometres). In this paper we present an approach that uses only gravity and snow density as a proxy for the age of the snow cover and land-use information to redistribute snow in alpine basins. The results are based on the hydrological modelling of the Austrian Inn Basin in Tyrol, Austria, more specifically the Ötztaler Ache catchment, but the findings hold for other tributaries of the river Inn. This transport model is implemented in the distributed rainfall–runoff model COSERO (Continuous Semi-distributed Runoff). The results of both model concepts with and without consideration of lateral snow redistribution are compared against observed discharge and snow-covered areas derived from MODIS satellite images. By means of the snow redistribution concept, snow accumulation over several years can be prevented and the snow depletion curve compared with MODIS (Moderate Resolution Imaging Spectroradiometer) data could be improved, too. In a 7-year period the standard model would lead to snow accumulation of approximately 2900 mm SWE (snow water equivalent) in high elevated regions whereas the updated version of the model does not show accumulation and does also predict discharge with more accuracy leading to a Kling–Gupta efficiency of 0.93 instead of 0.9. A further improvement can be shown in the comparison of MODIS snow cover data and the calculated depletion curve, where the redistribution model increased the efficiency (R2) from 0.70 to 0.78 (calibration) and from 0.66 to 0.74 (validation).
Frequency anomaly of groundwater level before major earthquakes in Taiwan
Authors: Yeh T.-K. , Chen C.-H. , Wang C.-H. , Wen S.
Published: November 2015

Abstract. Anomalous decreases on water levels were observed in 78 % of wells in central Taiwan about 250 days before the Chi-Chi earthquake whose magnitude is 7.6 on 20 September 1999. Variations in groundwater levels measured on anomalous wells from 1 August 1997 to 19 September 1999, were transferred into the frequency domain to unveil frequency characteristics. Analytical results show that amplitudes at the frequency band between 0.02 and 0.04 day−1 generally maintained at low stage and were apparently enhanced a few weeks before the Chi-Chi earthquake. Variations of amplitude at this particular frequency band were further examined along with other Taiwan earthquakes whose magnitude is larger than 6 from 1 August 1997 to 31 December 2009. Features of the enhanced amplitudes at the frequency band are consistently observed prior to the other two earthquakes during the 12.5-year study period. Result confirms that abnormal rise and fall changes in groundwater level yield an agreement with forward and backward surface displacements around epicenter prior to the Chi-Chi earthquake.
Superior coexistence: systematicALLY regulatING land subsidence BASED on set pair theory
Authors: Chen Y. , Gong S.-L.
Published: November 2015

Abstract. Anthropogenic land subsidence is an environmental side effect of exploring and using natural resources in the process of economic development. The key points of the system for controlling land subsidence include cooperation and superior coexistence while the economy develops, exploring and using natural resources, and geological environmental safety. Using the theory and method of set pair analysis (SPA), this article anatomises the factors, effects, and transformation of land subsidence. Based on the principle of superior coexistence, this paper promotes a technical approach to the system for controlling land subsidence, in order to improve the prevention and control of geological hazards.
Application of InSAR and gravimetric surveys for developing construction codes in zones of land subsidence induced by groundwater extraction: case study of Aguascalientes, Mexico
Authors: Pacheco-Martínez J. , Wdowinski S. , Cabral-Cano E. , Hernández-Marín M. , Ortiz-Lozano J. A. , Oliver-Cabrera T. , Solano-Rojas D. , Havazli E.
Published: November 2015

Abstract. Interferometric Synthetic Aperture Radar (InSAR) has become a valuable tool for surface deformation monitoring, including land subsidence associated with groundwater extraction. Another useful tools for studying Earth's surface processes are geophysical methods such as Gravimetry. In this work we present the application of InSAR analysis and gravimetric surveying to generate valuable information for risk management related to land subsidence and surface faulting. Subsidence of the city of Aguascalientes, Mexico is presented as study case. Aguascalientes local governments have addressed land subsidence issues by including new requirements for new constructions projects in the State Urban Construction Code. Nevertheless, the resulting zoning proposed in the code is still subjective and not clearly defined. Our work based on gravimetric and InSAR surveys is aimed for improving the subsidence hazard zoning proposed in the State Urban Code in a more comprehensive way. The study includes a 2007–2011 ALOS InSAR time-series analysis of the Aguascalientes valley, an interpretation of the compete Bouguer gravimetric anomaly of the Aguascalientes urban area, and the application of time series and gravimetric anomaly maps for improve the subsidence hazard zoning of Aguascalientes City.
Subsurface geology and aquifer system of the Nohbi Plain, central Japan
Authors: Makinouchi T. ,   Tokai Three-Prefecture Investigation Committee on Land Subsidence
Published: November 2015

Abstract. The Nohbi Plain is a typical coastal plain in Japan. The subsurface of this plain consists of alternating beds of marine clays in transgressive stages and fluvial gravels in regressive stages, and forms a groundwater basin. The aquifers are represented by the gravel beds in the regressive stages.
Potential of Holocene deltaic sequences for subsidence due to peat compaction
Authors: Stouthamer E. , van Asselen S.
Published: November 2015

Abstract. Land subsidence is a major threat for the livability of deltas worldwide. Mitigation of the negative impacts of subsidence, like increasing flooding risk, requires an assessment of the potential of the deltas' subsurfaces for subsidence. This enables the prediction of current and future subsidence and optimization of sustainable management strategies. In this paper we present a method to determine the amount of compaction within different Holocene deltaic peat sequences based on a case study from the Rhine-Meuse delta, the Netherlands, showing the potential of these sequences for subsidence due to peat compaction.
Compaction parameter estimation using surface movement data in Southern Flevoland
Authors: Fokker P. A. , Gunnink J. , de Lange G. , Leeuwenburgh O. , van der Veer E. F.
Published: November 2015

Abstract. The Southern part of the Flevopolder has shown considerable subsidence since its reclamation in 1967. We have set up an integrated method to use subsidence data, water level data and forward models for compaction, oxidation and the resulting subsidence to estimate the driving parameters. Our procedure, an Ensemble Smoother with Multiple Data Assimilation, is very fast and gives insight into the variability of the estimated parameters and the correlations between them. We used two forward models: the Koppejan model and the Bjerrum model. In first instance, the Bjerrum model seems to perform better than the Koppejan model. This must, however, be corroborated with more elaborate parameter estimation exercises in which in particular the water level development is taken into account.
The effect of the depth and groundwater on the formation of sinkholes or ground subsidence associated with abandoned room and pillar lignite mines under static and dynamic conditions
Authors: Aydan Ö. , Ito T.
Published: November 2015

Abstract. It is well known that some sinkholes or subsidence take place from time to time in the areas where abandoned room and pillar type mines exist. The author has been involved with the stability of abandoned mines beneath urbanized residential areas in Tokai region and there is a great concern about the stability of these abandoned mines during large earthquakes as well as in the long term. The 2003 Miyagi Hokubu and 2011 Great East Japan earthquakes caused great damage to abandoned mines and resulted in many collapses. The author presents the effect of the depth and groundwater on the formation of sinkholes or ground subsidence associated with abandoned room and pillar lignite mines under static and dynamic conditions and discusses the implications on the areas above abandoned lignite mines in this paper.
Physical experiments of land subsidence within a maar crater: insights for porosity variations and fracture localization
Authors: Cerca M. , Rocha L. , Carreón-Freyre D. , Aranda J.
Published: November 2015

Abstract. We present the results of a series of physical models aiming to reproduce rapid subsidence (at least 25 m in 30 years) observed in the sediments of a maar crater caused by extraction of groundwater in the interconnected adjacent aquifer. The model considered plausible variations in the geometry of the crater basement and the measured rate of groundwater extraction (1 m per year in the time interval from 2005 to 2011) in 15 wells located around the structure. The experiments were built within a rigid plastic bowl in which the sediments and rocks of the maar sequence were modeled using different materials: (a) plasticine for the rigid country rock, (b) gravel for the fractured country rock forming the diatreme fill and, (c) water saturated hollow glass microbeads for the lacustrine sedimentary fill of the crater. Water table was maintained initially at the surface of the sediments and then was allowed to flow through a hole made at the base of the rigid bowl. Water extraction provoked a sequence of gentle deformation, fracturing, and faulting of the surface in all the experiments. Vertical as well as lateral displacements were observed in the surface of the experiments. We discuss the results of 2 representative models. The model results reproduced the main geometry of the ring faults affecting the crater sediments and helps to explain the diversity of structures observed in relation with the diatreme geometry. The surface of the models was monitored continuously with an optical interferometric technique called structured light projection. Images collected at nearly constant time intervals were analyzed using the ZEBRA software and the obtained interferometric pairs permitted to analyze the full field subsidence in the model (submilimetric vertical displacements). The experiments were conducted at a continuous flow rate extraction and show a also a linear subsidence rate. Comparison among the results of the physical models and the fault system associated to subsidence in the maar show that fault geometry in the sedimentary sequence imitates closely the geometry of the volcanic basement.
Evolution of the techniques for subsidence monitoring at regional scale: the case of Emilia-Romagna region (Italy)
Authors: Bitelli G. , Bonsignore F. , Pellegrino I. , Vittuari L.
Published: November 2015

Abstract. The recent decades have seen a significant evolution of the methodologies and techniques for the monitoring of subsidence on a regional scale: from the traditional levelling technique to GNSS and finally to SAR interferometry. The case study of Emilia-Romagna, Italy, is a prime example of this evolution. As known, the Emilia-Romagna plain is subject to a phenomenon of subsidence with a natural and an anthropogenic component, both of varying amounts depending on the area. The first contributes a few mm/year; the second, particularly evident in the last 60 years, is mainly correlated to excessive withdrawal of fluids from underground and reaches higher values (in the past, subsidence rates of several cm per year were observed in the Po delta and near Bologna). The geodetic monitoring of subsidence started in the 1950s by different entities, establishing and measuring levelling networks of varying size and with various characteristics, mainly located where the phenomenon was most clearly manifest. These local initiatives were not able to provide a consistent understanding of the phenomenon throughout the entire Emilia-Romagna plain. The first regional-scale monitoring of the Emilia-Romagna plain was initiated in 1999, with a large levelling network (about 3000 km) and a coupled network of 60 GNSS points. In subsequent years, the monitoring approach has mainly focused on the most modern remote sensing techniques integrated with each other, with the adoption of the method DInSAR calibrated to a GNSS Continuous Operating Reference Stations (CORS) database. The application of DInSAR methods resulted in subsidence maps with a greater level of detail. The paper analyzes the methodology choices made during 1999–2012, through three successive campaigns that adopted and integrated the different techniques.
InSAR data for monitoring land subsidence: time to think big
Authors: Ferretti A. , Colombo D. , Fumagalli A. , Novali F. , Rucci A.
Published: November 2015

Abstract. Satellite interferometric synthetic aperture radar (InSAR) data have proven effective and valuable in the analysis of urban subsidence phenomena based on multi-temporal radar images. Results obtained by processing data acquired by different radar sensors, have shown the potential of InSAR and highlighted the key points for an operational use of this technology, namely: (1) regular acquisition over large areas of interferometric data stacks; (2) use of advanced processing algorithms, capable of estimating and removing atmospheric disturbances; (3) access to significant processing power for a regular update of the information over large areas. In this paper, we show how the operational potential of InSAR has been realized thanks to the recent advances in InSAR processing algorithms, the advent of cloud computing and the launch of new satellite platforms, specifically designed for InSAR analyses (e.g. Sentinel-1a operated by the ESA and ALOS2 operated by JAXA). The processing of thousands of SAR scenes to cover an entire nation has been performed successfully in Italy in a project financed by the Italian Ministry of the Environment. The challenge for the future is to pass from the historical analysis of SAR scenes already acquired in digital archives to a near real-time monitoring program where up to date deformation data are routinely provided to final users and decision makers.
Inversion of double-difference measurements from optical levelling for the Groningen gas field
Authors: Fokker P. A. , Van Thienen-Visser K.
Published: November 2015

Abstract. Hydrocarbon extraction lead to compaction of the gas reservoir which is visible as subsidence on the surface. Subsidence measurements can therefore be used to better estimate reservoir parameters. Total subsidence is derived from the result of the measurement of height differences between optical benchmarks. The procedure from optical height difference measurements to absolute subsidence is an inversion, and the result is often used as an input for consequent inversions on the reservoir. We have used the difference measurements directly to invert for compaction of the Groningen gas reservoir in the Netherlands. We have used a linear inversion exercise to update an already existing reservoir compaction model of the field. This procedure yielded areas of increased and decreased levels of compaction compared to the existing compaction model in agreement with observed discrepancies in porosity and aquifer activity.
Inverse modeling using PS-InSAR for improved calibration of hydraulic parameters and prediction of future subsidence for Las Vegas Valley, USA
Authors: Burbey T. J. , Zhang M.
Published: November 2015

Abstract. Las Vegas Valley has had a long history of surface deformation due to groundwater pumping that began in the early 20th century. After nearly 80 years of pumping, PS-InSAR interferograms have revealed detailed and complex spatial patterns of subsidence in the Las Vegas Valley area that do not coincide with major pumping regions. High spatial and temporal resolution subsidence observations from InSAR and hydraulic head data were used to inversely calibrate transmissivities (T), elastic and inelastic skeletal storage coefficients (Ske and Skv) of the developed-zone aquifer and conductance (CR) of the basin-fill faults for the entire Las Vegas basin. The results indicate that the subsidence observations from PS-InSAR are extremely beneficial for accurately quantifying hydraulic parameters, and the model calibration results are far more accurate than when using only water-levels as observations, and just a few random subsidence observations. Future predictions of land subsidence to year 2030 were made on the basis of existing pumping patterns and rates. Simulation results suggests that subsidence will continue in northwest subsidence bowl area, which is expected to undergo an additional 11.3 cm of subsidence. Even mitigation measures that include artificial recharge and reduced pumping do not significantly reduce the compaction in the northwest subsidence bowl. This is due to the slow draining of thick confining units in the region. However, a small amount of uplift of 0.4 cm is expected in the North and Central bowl areas over the next 20 years.
Poroelastic modeling to assess the effect of water injection for land subsidence mitigation
Authors: Aichi M. , Tokunaga T.
Published: November 2015

Abstract. The possible effect of water injection to mitigate land subsidence was studied through numerical simulations based on the theory of poroelasticity. The Kujukuri Plain, Japan, was chosen as a study area. The effect of past injection was evaluated by comparing a model with injection and the one without injection. The calculated results suggested that the past injection played a significant role to reduce land subsidence. For achieving more effective mitigation practices in the future, we proposed to install injection wells in shallower formations. The effect of proposed injection method to mitigate land subsidence from 2014 to 2030 was also investigated. The calculated results show that the proposed method can work similarly by lesser water injection than the past method. The results also indicate that the upper limit of injection rate should be carefully determined to control the pore pressure build-up in the formation to be small enough to avoid formation failure.
Numerical and experimental study of strata behavior and land subsidence in an underground coal gasification project
Authors: Sirdesai N. N. , Singh R. , Singh T. N. , Ranjith P. G.
Published: November 2015

Abstract. Underground Coal Gasification, with enhanced knowledge of hydrogeological, geomechanical and environmental aspects, can be an alternative technique to exploit the existing unmineable reserves of coal. During the gasification process, petro-physical and geomechanical properties undergo a drastic change due to heating to elevated temperatures. These changes, caused due to the thermal anisotropy of various minerals, result in the generation of thermal stresses; thereby developing new fracture pattern. These fractures cause the overhead rock strata to cave and fill the gasification chamber thereby causing subsidence. The degree of subsidence, change in fluid transport and geomechanical properties of the rock strata, in and around the subsidence zone, can affect the groundwater flow. This study aims to predict the thermo-geomechanical response of the strata during UCG. Petro-physical and geomechanical properties are incorporated in the numerical modelling software COMSOL Multiphysics and an analytical strength model is developed to validate and further study the mechanical response and heat conduction of the host rock around the gasification chamber. Once the problems are investigated and solved, the enhanced efficiency and the economic exploitation of gasification process would help meet country's energy demand.