New marine ΔR values for Arctic Canada

For more than four decades, the reporting of ¹⁴C dates on marine molluscs from Arctic Canada has been notable for the lack of consistently applied marine reservoir corrections. We propose that the common approach of reporting Canadian Arctic marine ¹⁴C dates using presumed time-invariant reservoir corrections be abandoned in favour of calibration of ¹⁴C dates, using the current standard protocol. This approach best facilitates inter- and intra-regional correlation, and correlation with other geochronometers. In order to enable the consistent calibration of marine ¹⁴C dates from Arctic Canada, we analysed a ¹⁴C database of 108 marine mollusc samples collected live between 1894 and 1956, and determined regional reservoir offset values (ΔR) for eight oceanographically distinct regions. The following new ΔR values should be used for ¹⁴C calibration: NW Canadian Arctic Archipelago, 335 ± 85 yrs; Foxe Basin, 310 ± 90 yrs; NE Baffin Island, 220 ± 20 yrs; SE Baffin Island, 150 ± 60 yrs; Hudson Strait, 65 ± 60 yrs; Ungava Bay, 145 ± 95 yrs; Hudson Bay, 110 ± 65 yrs; and James Bay, 365 ± 115 yrs.     

Sublimation-driven evolution of the local radius and the moment of inertia of short-period comets

This article is a continuation of the previous one considering the evolution of a long-period comet. The changes of the local radius and the moment of inertia as well as the orientation of the rotation axis are calculated. With reference to the previous model, the time-dependent orbital parameters are introduced. The procedure of sublimation-driven evolution is implemented to the comets 67P/Churyumov-Gerasimenko, 9P/Tempel 1, and 81P/Wild. The inclination of the rotation axis of Comet Ch-G is calculated. The position of the rotation axis is a result of the best fit of the water production rate curve received from modelling to the observational water production rate curve. The method is verified through application to Comets 9P/Tempel 1 and 81P/Wild with well-known positions of the rotation axes. The best fit is for inclination of the rotation axis which is close to the position of the rotation axis with minimum energy (maximum of the moment of inertia). For the best fitted position of the rotation axis I = 90° and Φ = 60°, the largest decrease of radius was about 5.6 m in the northern polar region. The smallest decrease of radius, of about 0.3 m, was noticed on cometographic latitudes between 39° and 46°.     

Natural Radioactivity at the Sin Quyen Iron-Oxide-Copper-Gold Deposit in North Vietnam

The field radiometric and laboratory measurements were performed at the Sin Quyen copper deposit in North Vietnam. The field gamma-ray spectrometry indicated the concentration of uranium ranging from 5.5 to 87 ppm, thorium from 5.6 to 33.2 ppm, and potassium from 0.3 to 4.7%. The measured dose rates ranged from 115 to 582 nGy/h, the highest doses being at the copper ore. Concentrations in the solid samples were in the range of 20–1700 Bq/kg for uranium, 20–92.7 Bq/kg for thorium, and 7–1345 Bq/kg for potassium. The calculated doses were from 22 to 896 nGy/h; both measured and calculated dose rates are mostly related to uranium. Concentrations of radium in water samples were below 0.17 Bq/L. Uranium in water samples was significantly higher than the hydrogeological background; the maximum of 13 Bq/L was at the waste zone pool, but neither radium nor uranium were present in tap water. Radon concentration in the dwelling air was from 42 to 278 Bq/m³ for ²²²Rn and from 8 to 193 Bq/m³ for ²²⁰Rn. The estimated committed dose rates were principally related to ²²²Rn concentration and ranged from 1.1 to 8.1 mSv/y.     

Very Low Frequency Electromagnetic Induction Surveys in Hydrogeological Investigations; Case Study from Poland

In 2011, a geophysical survey was carried out in the surroundings of the Jagiellonian University in Cracow, using a Very Low Frequency method. The measurements were designed to determine the reason of frequent flooding of the lowest level of the building. The main objective of the study was to find out from where and in which way the rainwater seeps into the building and how this problem can be solved in the least invasive manner. The aim of geophysical methods was also to provide necessary information that will enable the construction of a hydro-geological model of the local environment. The interpretation revealed the presence of a sandy gutter surrounded by impermeable clay. There is a big resistivity contrast between those layers. Their location and approximate dimensions were determined.     

Combined analysis of precipitation and water deficit for drought hazard assessment

Abstract

The combined analysis of precipitation and water scarcity was done with the use of the Standardized Precipitation Index (SPI) and the Standardized Runoff Index (SRI), developed as a monthly, two-variable SPI-SRI indicator to identify different classes of hydrometeorological conditions. Stochastic analysis of a long-term time series (1966–2005) of monthly SPI-SRI indicator values was performed using a first-order Markov chain model. This provided characteristics of regional features of drought formation, evolution and persistence, as well as tools for statistical long-term drought hazard prediction. The study was carried out on two subbasins of the Odra River (Poland) of different orography and land use: the mountainous Nysa K?odzka basin and the lowland, agricultural Prosna basin. Classification obtained with the SPI-SRI indicator was compared with the output from the NIZOWKA model that provided identification of hydrological drought events including drought duration and deficit volume. Severe and long-duration droughts corresponded to SPI-SRI Class 3 (dry meteorological and dry hydrological), while severe but short-term droughts (lasting less than 30 days) corresponded to SPI-SRI Class 4 (wet meteorological and dry hydrological). The results confirm that, in Poland, meteorologically dry conditions often shift to hydrologically dry conditions within the same month, droughts rarely last longer than 2 months and two separate drought events can be observed within the same year.     

Analysis and usage of linear relationships between the magnetic field components recorded by INTERMAGNET

An analysis of linear relationships between the ground-level components of the Earth’s magnetic field measured at different sites is a relatively new topic compared to the analysis of data at a single location. The data collected by the INTERMAGNET observation network provide perfect set of data to which this analysis can be used. An important tool in this analysis may be developing a method of determination of the impulse response for linear systems in the time domain. An advantage of calculations in the time domain over the generally known and applied methods in the frequency domain is the possibility of determining prediction of output signals. By that, simultaneously with the analysis of linear relationships, a tool for recovering missing records in incomplete observation data is obtained. Filling-in the missing data may increase interest and possibility of using the observational data by researchers experimenting with the analysis in the frequency domain where gaps in data records are a significant limitation.     

An approach to response-based reliability analysis of quasi-linear Errors-in-Variables models

The paper presents an approach to internal reliability analysis of observation systems known as Errors-in-Variables (EIV) models with parameters estimated by the method of least squares. Such problems are routinely treated by total least squares adjustment, or orthogonal regression. To create a suitable environment for derivations in the analysis, a general nonlinear form of such EIV models is assumed, based on a traditional adjustment method of condition equations with unknowns, also known as the Gauss–Helmert model. However, in order to apply the method of reliability analysis based on the approach to response assessment in systems with correlated observations, presented in the earlier work of this author, it was necessary to confine the considerations to a quasi-linear form of the Gauss–Helmert model, representing quasi-linear EIV models. This made it possible to obtain a linear disturbance/response relationship needed in that approach. Several specific cases of quasi-linear EIV models are discussed. The derived formulas are consistent with those already functioning for standard least squares adjustment problems. The analysis shows that, as could be expected, the average level of response-based reliability for such EIV models under investigation is lower than that for the corresponding standard linear models. For EIV models with homoscedastic and uncorrelated observations, the relationship between the average reliability indices for the independent and the dependent variables is formulated for multiple regression and coordinate transformations. Numerical examples for these two applications are provided to illustrate this analysis.     

Graphically supported evaluation of mapping techniques used in presenting spatial accessibility

ABSTRACT

Given the rising availability of alternative ways of spatial data mapping, there is a growing need to study their usability. An important aspect here is the diversity of the cartographic visualizations that are used to draw conclusions about the usability of various mapping techniques. In our study we evaluated the usability of six various mapping techniques used in presenting spatial accessibility, taking into consideration four components: effectiveness and efficiency (objective criteria) and graphical attractiveness and user-perceived effectiveness (subjective criteria). Using Internet questionnaires, we conducted a graphical perception experiment with respondents performing tasks on a hypothetical monocentric road network model displayed using mapping techniques of spatial accessibility, differing in the applied parameters of graphical and non-graphical factors influencing effectiveness and efficiency. The results showed that non-graphical factors had a greater influence than the graphical factors. In total usability comparison the three-dimensional (3D) point technique was ranked the highest, while the worst result was achieved by the 3D area technique. The proposed graphical form of study results made it possible to compare the influence of various effectiveness factors, to analyze mapping techniques in terms of considered criteria and finally to present their total usability using a chart inspired by Uhorczak’s typogram.     

A protoceratopsid skeleton with an associated track from the Upper Cretaceous of Mongolia

The Djadokhta Formation of the Gobi Desert is known for the number and diversity of dinosaur and other vertebrate bones and skeletons found there, but only theropod, hadrosaur and supposed ankylosaurid footprints have been reported from this stratum. Dinosaur footprints are also noted from the Nemegt Formation, and occur as typical dinosaur track accumulations (tracksites). An articulated protoceratopsid skeleton - specimen ZPAL Mg D-II/3 - was collected by the Polish-Mongolian Expedition of 1965 from the Djadokhta Formation of Flaming Cliffs in Mongolia. Recently, the natural cast of a tetradactyl digitigrade footprint was found underneath the pelvic girdle while the skeleton and matrix were being prepared. This is possibly the first find of a dinosaur track in close association with an articulated skeleton. Although Protoceratops is an extremely common dinosaur in Mongolia, its footprints have never previously been reported from the Late Cretaceous of the Gobi Desert.