Extending the Application of a Shale Volume Estimation Formula Derived from Factor Analysis of Wireline Logging Data

A multivariate statistical procedure is developed for the estimation of shale volume in clastic sedimentary formations. The method offers an alternative for extracting the shale content from borehole geophysical measurements. Factor analysis of various well-logging data types generates a new well log that correlates with the shale content of shaly-sandy rocks. The mathematical relationship between shale volume and factor scores is represented by a nonlinear equation, which seems to be applicable for data sets originating from different sedimentary basins. A comparative study is made between three different data sets originating from Hungary and the United States of America in order to check the validity of the proposed empirical formula. Shale volumes predicted from factor analysis are confirmed by estimates from independent deterministic and inverse modeling. Petrophysical information derived by factor analysis of logs recorded in deep wells can be used for a more accurate and reliable estimation of effective porosity and absolute permeability of reservoir rocks, for decreasing the estimation error of inversion estimates and for reducing the ambiguity in the solution of the well-logging inverse problem.     

Multi-scale Transport Processes Observed in the Boundary Layer over a Mountainous Island

Over complex terrain, convection and thermally-driven circulations simultaneously occur under fair weather conditions during the day. To investigate these processes on the basis of observations, simultaneous measurements on different scales are necessary. Comprehensive measurements with the mobile observation platform KITcube were performed on the mountainous island of Corsica during the HYdrological cycle in Mediterranean EXperiment (HyMeX) field campaign in late summer and autumn 2012. Using a case study, the benefit of integrated measurement systems and coordinated scan strategies was demonstrated, and experimental evidence of, and new insights into, convective and advective transport processes in a valley were obtained. Convection, thermally-driven circulations and topographic and advective venting led to the diurnal cycle of temperature, humidity and wind over complex terrain in the mountain atmospheric boundary layer (mountain ABL), which was deeper than an ABL over homogeneous terrain under equal surface forcing. Due to the combined transport processes on different scales, the mountain ABL in a valley also extended beyond the convection layer, which was characterized by surface-based, buoyancy-driven turbulent mixing. Strong subsidence, with a vertical velocity of about 1 m s \(^{-1}\) , was present within the mountain ABL for several hours around noon and suppressed the convection-layer growth. Above the layer with subsidence, elevated vertical motions, consisting of alternating updrafts and downdrafts, occurred. Once the convection layer grew to the bottom of the layer with elevated vertical motions, surface-based convective cells occasionally coupled to the elevated updrafts, as a result of which the convection layer rapidly deepened.     

A method to detect and characterize sub‐daily flow fluctuations

Hydro peaking causes an important environmental impact on running water ecosystems. Many affected rivers have a poor ecological status. In rivers affected by hydro peaking, the flow conditions are highly complex and difficult to grasp. To develop a general framework for detecting and characterizing sub‐daily flow fluctuations, we analysed more than 500 Austrian hydrographs, covering the whole range from unimpacted to heavily impacted rivers. Different fluctuation types could be identified according to the potential source: e.g. sub‐daily flow fluctuations caused by hydro peaking, rainfall or snow and glacier melt. Additionally, the term ‘hydro fibrillation’ was established, to indicate frequently occurring artificial fluctuations with comparably low intensities. An automatic procedure was used to detect frequency and intensity of each flow fluctuation. Using variables based on duration curves of flow fluctuation rates (ramping rates), amplitudes, flow ratios, durations and daily numbers of fluctuations, a predictive model (linear discriminant analysis) was fitted to classify hydrographs into predominant fluctuation regimes. This is the basis for a detailed investigation of present sub‐daily flow regimes and to analyse the differences between the regimes. Based on the results, we finally propose a general framework that enables a standardized assessment of flow fluctuations regarding event intensities and/or event timing. The proposed framework offers a standardized selection of particular flow fluctuations referring to increase and decrease events separately. The selection of specific flow fluctuations can be defined with respect to several research questions (e.g. ecologically relevant fluctuations), which offers a wide range of applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Bayesian analysis of a dynamical model for the spread of the Usutu virus

The Usutu virus is an arbovirus transmitted by mosquitoes and causing disease in birds. The virus was detected in Austria for the first time in 2001, while a major outbreak occurred in 2003. Rubel et al. (2008) developed a nine-compartment deterministic SEIR model to explain the spread of the disease. We extended this to a hierarchical Bayes model assuming random variation in temperature data, in reproduction data of birds, and in the number of birds found to be infected. The model was implemented in R, combined with the FORTRAN subroutine for the original deterministic model. Analysis was made by MCMC using a random walk Metropolis scheme. Posterior means, medians, and credible intervals were calculated for the parameters. The hierarchical Bayes approach proved to be fruitful in extending the deterministic model into a stochastic one. It allowed for Bayesian point and interval estimation and quantification of uncertainty of predictions. The analysis revealed that some model parameters were not identifiable; therefore we kept constant some of them and analyzed others conditional on them. Identifiability problems are common in models aiming to mirror the mechanism of the process, since parameters with natural interpretation are likely to exhibit interrelationships. This study illustrated that Bayesian modeling combined with conditional analysis may help in those cases. Its application to the Usutu model improved model fit and revealed the structure of interdependencies between model parameters: it demonstrated that determining some of them experimentally would enable estimation of the others, except one of them, from available data.     

Recuperated optically stimulated luminescence dating of middle-size quartz grains from the Palaeolithic site of Bonneval (Eure-et-Loir,France)

The site of Bonneval (France) exhibits a 6 m thick stratigraphical sequence in which Middle and Lower Palaeolithic artefacts were discovered. The stratigraphy of the site consists of an alternation of loess-like silt layers deposited along glacial stages, and paleosoil horizons corresponding to the vegetal stabilization of the area during interglacials. These layers hence provide past environmental informations and can be used as stratigraphical markers and compared with well dated sequences of Northern France. Eight sediment samples from this Middle and Upper Pleistocene sequence were dated using the recuperated optically stimulated luminescence (Re-OSL) signal of quartz grains. The middle-size fraction (40–63 μm) shows a good reproducibility of the OSL signals which allows the application of a multiple-aliquot additive-dose approach for D_e determination. For all samples, the growth curves are linear up to an accumulated dose of 3000 Gy. The Re-OSL ages range from ～100 to ～450 ka and are in good agreement with the independent chronological information; they establish when handaxe industries have been made during the Middle and Upper Pleistocene in the Paris Basin.     

双能CT的基本原理、应用和未来展望(英文)

断层影像(CT)的图像对比度与扫描所用的X光源能谱分布有很大关系。传统CT使用具有能谱分布的一个光源进行成像,有时会出现信息模糊致使两种不同材料在CT图像上完全相同。双能CT使用两个不同分布的能谱对物体进行成像,能够消除单能谱情况下的信息模糊。虽然双能CT的基本概念由来已久,但最近商业系统的出现使双能CT迅速成为一个热点。我们首先概述了双能CT的基本物理原理和双能信号处理方法,包括促使双能CT进入现代医学成像的关键技术。其次,双能CT的应用已非常广泛,本文从其在临床应用角度进行了详细介绍使读者有所了解。最后,我们简要探讨了当前的两个技术发展领域:光子技术探测器和技术合成CT。     

Sources, loads and dispersion of dissolved inorganic nutrients in Paranaguá Bay

The present study focuses on the nutrient sources and gradients in Paranaguá Bay (Southern Brazil), where nutrient inputs are related to losses from fertilizer loading in Paranaguá harbour and the discharge of untreated waste water. The input of dissolved inorganic nutrients to the bay from the harbour and city, as well as from river and atmospheric deposition, amounted to 642?t?year^?1 DIN-N and 92?t?year^?1 PO₄-P. Harbour losses accounted for 6?% of total DIN-N and 39?% of total PO₄-P loads to the bay, whereas sewage inputs from the city were responsible for 21?% and 22?%, respectively. River inputs made up 68?% of DIN-N, mainly in the form of nitrate, and 35?% of PO₄-P loads, while atmospheric wet deposition was estimated to be in the order of 5?% of DIN-N and 4?% of PO₄-P loads. Local maxima in nutrient levels deriving from highly concentrated sewage discharge were observed in front of the harbour and city of Paranaguá, but the plumes are diluted rapidly due to short residence times. DIN concentrations are negatively correlated with salinity, indicating the importance of freshwater input as a main factor controlling nitrogen distribution. Elevated phosphate levels in the stratified middle section of the bay may result both from harbour emissions and phosphate remobilization from sediments. Generally lower DIN and PO₄ concentrations during the warmer rainy season are supposed to be due to intensified assimilation rates especially in the middle section of the bay where dense phytoplankton blooms are observed. The bay as a whole cannot be classified as being seriously eutrophic, albeit eutrophication symptoms prevail in some restricted locations in front of Paranaguá harbour.     

Sources,loads and dispersion of dissolved inorganic nutrients in Paranaguá Bay

The present study focuses on the nutrient sources and gradients in Paranaguá Bay (Southern Brazil), where nutrient inputs are related to losses from fertilizer loading in Paranaguá harbour and the discharge of untreated waste water. The input of dissolved inorganic nutrients to the bay from the harbour and city, as well as from river and atmospheric deposition, amounted to 642 t year⁻¹ DIN-N and 92 t year⁻¹ PO₄-P. Harbour losses accounted for 6 % of total DIN-N and 39 % of total PO₄-P loads to the bay, whereas sewage inputs from the city were responsible for 21 % and 22 %, respectively. River inputs made up 68 % of DIN-N, mainly in the form of nitrate, and 35 % of PO₄-P loads, while atmospheric wet deposition was estimated to be in the order of 5 % of DIN-N and 4 % of PO₄-P loads. Local maxima in nutrient levels deriving from highly concentrated sewage discharge were observed in front of the harbour and city of Paranaguá, but the plumes are diluted rapidly due to short residence times. DIN concentrations are negatively correlated with salinity, indicating the importance of freshwater input as a main factor controlling nitrogen distribution. Elevated phosphate levels in the stratified middle section of the bay may result both from harbour emissions and phosphate remobilization from sediments. Generally lower DIN and PO₄ concentrations during the warmer rainy season are supposed to be due to intensified assimilation rates especially in the middle section of the bay where dense phytoplankton blooms are observed. The bay as a whole cannot be classified as being seriously eutrophic, albeit eutrophication symptoms prevail in some restricted locations in front of Paranaguá harbour.