bluuebunny/crossref_metadata_2025 huggingface dataset:
‘King of Kings of Africa’
Authors: Gruber Christiane
Published: July 2018

During the 2011 uprisings, artists and cultural agents unleashed biting pictorial forms of ridicule in Libya’s public domain. Their chief target was Muʿammar Qaddafi, the ‘Brother Leader’ of the Libyan Arab Republic and the so-called ‘King of Kings of Africa’. After failing to win support from Arab governments, Qaddafi campaigned for African unity, fashioning himself as a traditional sub-Saharan chief during the decade leading up to the ‘Arab Spring’. His bombastic African title, his Afro-like (shafshufa) hairstyle and his eye-catching robes made him an easy target for visual satire, which turned visibly more racist when he and his son, Sayf al-Islam, resorted to using mercenaries from the Sudan, Chad, Niger and Mali to violently suppress street demonstrations. Throughout the uprisings, anti-government actors sought to degrade Qaddafi through the use of ethnic stereotypes, revealing that, in the particular case of Libya, satirical contentions during the so-called ‘Arab Spring’ were not just transgressive and factional, but instrumentally racist as well.
A new species of Aethra (Decapoda: Brachyura: Aethridae) from the early Serravallian (middle Miocene) of the Medobory Hills (Ukraine)
Authors: OSSÓ ÀLEX
Published: July 2018

A new species of the genus Aethra (A. stalennyii n. sp.) from the Badenian (middle Miocene) reef frameworks of the Maksymivka quarry in the Medobory Hills, near Ternopil (Ukraine) is described herein. Aethra stalennyii n. sp. represents the first fossil occurrence of the genus known to date. Aethra stalennyii n. sp. inhabited a very similar habitat to those all the extant congeners live in. The presence of Aethra in the middle Miocene of the Central Paratethys adds further emphasis on close affinities between Tethyan reef-associated decapod assemblages and their modern counterparts in the Indo-West Pacific waters. Aethra stalennyii n. sp. represents the first report of Aethra in the fossil record. Possible origin of the genus and subsequent migration eastward is discussed.
Predictors for Prognosis in Patients With Nonfatal Pulmonary Embolism: A Registry-Based Cohort Study
Authors: Bosevski Marijan , Krstevski Gorjan , Gjorgievski Atanas , Mitevska Irena , Kostovska Elizabeta Srbinovska
Published: July 2018

The article’s aim was to determine predictors for short- and long-term prognosis of patients with pulmonary embolism (PE). Cohort prospective study based on the National registry on venous thromboembolism. Eighty-four patients with PE, on age 60.3 + 12.5 years, were selected and followed up in a prospective study. Pulmonary embolism was confirmed by computed tomography angiography in all the patients, while deep venous thrombosis was confirmed by ultrasound in 21 patients. Study population was followed up for 6.7 months. Multivariate regression analysis was done where right ventricular (RV) diameter (mean 37.5 mm), systolic pulmonary artery pressure (68 ± 23 mm Hg) measured by echocardiography, d-dimer level at baseline 2654.5 ± 420.3 ng/mL, number of comorbidities (2.4 ± 0.7), and present symptoms (3.1 ± 0.9) entered the model. The model was age-adjusted. d-dimer level was revealed as a predictor for the length of hospitalization (β = .25, P = .05) and RV diameter as a factor for duration of anticoagulation (β = .29, P = .05). Our results imply that the baseline measurement of these parameters independently influence both the short-term and long-term prognosis of patients with nonfatal PE.
A hierarchical access control scheme based on Lagrange interpolation for mobile agents
Authors: Hsiao Tsung-Chih , Wu Zhen-Yu , Chen Tzer-Long , Chung Yu-Fang , Chen Tzer-Shyong
Published: July 2018

The mobile agent is functioning as an information exchanger with hosts. In order to reduce the communication time that the host sent to the members of a large system. This article proposes to use a function defined by Lagrange polynomial to compute decryption key. Each host will be given a decryption key to access the confidential document by inputting a secret key into an interpolation function which is generated from Lagrange interpolation. Since tasks are done by the mobile agent, the whole process will be performed within a short time period because there is no physical connection between the end devices. The information exchange occurs at the end hosts.
Effect of the vertical relative motion of stock/switch rails on wheel–rail contact mechanics in switch panel of railway turnout
Authors: Ma Xiaochuan , Wang Ping , Xu Jingmang , Chen Rong
Published: July 2018

In order to enable the vehicle to change among the tracks, the stock and switch rails are separated and provided with different rail resilience levels on the baseplate in the railway turnout switch panel. Therefore, there will be vertical relative motion between stock/switch rails under wheel loads, and the relative motion will change the combined profile of stock/switch rails and consequently affect the wheel–rail contact mechanics. A method is developed in this article to investigate the effect of the relative motion of stock/switch rails on the wheel–rail contact mechanics along the railway turnout switch panel. First, the possible rigid wheel–rail contact points, called primary and secondary stock/switch rail contact points, are calculated based on the trace line method; second, the actual contact points are determined by the presented equations; finally, the distribution of wheel–rail contact forces on the stock/switch rails is obtained based on the continuity of interface displacements and forces. A numerical example is presented in order to investigate the effect of the relative motion of stock/switch rails on the wheel–rail contact points, stresses, and forces, and the results are presented and discussed.
Healthy hearts at hectic pace: From daily life stress to abnormal cardiomyocyte function and arrhythmias
Authors: Barbiero Silvia , Aimo Alberto , Castiglione Vincenzo , Giannoni Alberto , Vergaro Giuseppe , Passino Claudio , Emdin Michele
Published: July 2018

The hectic pace of contemporary life is a major source of acute and chronic stress, which may have a deleterious impact on body health . In the field of cardiovascular disease, acute emotional stress has been associated with coronary spasm and Takotsubo cardiomyopathy, whereas the manifestations of chronic stress have been overlooked, and most underlying pathophysiology remains to be elucidated. Chronic stress affects the neuronal circuitry composed of cortico-limbic structures and the nuclei regulating autonomic function, eliciting a sympatho-vagal imbalance, characterised by adrenergic activation and vagal withdrawal. Sympathetic terminals are connected to cardiomyocytes in a quasi-synaptic way, producing the so called ‘neuro-cardiac junction'. During chronic stress, norepinephrine release is increased, leading to overstimulation of cardiomyocytes via β1-adrenergic receptors, influencing mainly calcium dynamics, and β2-adrenergic receptors, which control housekeeping functions. The circadian rhythm of cardiomyocytes is then impaired, with elongation of the catabolic (‘light’ phase) over the anabolic (‘nocturnal’) phase. This leads to a depletion of cell energy storage, and a decreased turnover of cell constituents. Even cell interactions are affected, as coupling between cardiomyocytes decreases while coupling between cardiomyocytes and fibroblasts increases. The ultimate results are changes in the shape and velocity of action potential, fibroblast activation and deposition of extracellular matrix. These alterations may predispose to arrhythmias and may favour the development of a stress-related cardiomyopathy. A better comprehension of this cascade of events may allow us to identify screening protocols and treatment strategies (meditation, yoga, physical activity, psychological assistance, β-blockers) to prevent or relieve ongoing cardiac damage.
A depth variant seismic wavelet extraction method for inversion of poststack depth-domain seismic data
Authors: Zhang Rui , Deng Zhiwen
Published: July 2018

Prestack depth seismic imaging is increasingly being used in industry, which has also led to an increasing need for its inversion results, such as acoustic impedance (AI), for reservoir characterization. Conventional seismic inversion methods for reservoir characterization are usually implemented in the time domain. A depth-time conversion would be required before inversion of depth-domain seismic data, which would depend on an accurate velocity model and a fine time-depth conversion algorithm. Thus, it could be beneficial that we can directly invert the depth migrated seismic data. Depth-domain seismic data could indicate a strong nonstationarity, such as spectral variation, which makes it difficult to use a constant wavelet for direct inversion in depth. To address this issue, we have developed a new wavelet extraction method by using a depth-wavenumber decomposition technique, which can generate depth variant wavelets to accommodate the nonstationarity of the depth-domain seismic data. The synthetic and real data applications have been used to test the effectiveness of our method. The directly inverted depth-domain AI indicates a good correlation with well-log data and a strong potential for reservoir characterization.
Geophysical properties of an epithermal Au-Ag deposit in British Columbia, Canada
Authors: Abbassi Bahman , Cheng Li Zhen , Richards Jeremy P. , Hübert Juliane , Legault Jean M. , Rebagliati Mark , Witherly Ken
Published: July 2018

The Newton Au-Ag deposit is an intermediate sulfidation state epithermal system in British Columbia, Canada. Multiple types of geophysical data are interpreted and evaluated with drillcore petrophysical, geochemical, and geologic observations to better understand the geophysical signature of the Newton epithermal system. Airborne [Formula: see text]-ray data sets indicate elevated emission counts of K, eTh, and eU over the Newton epithermal system, which are caused by hydrothermal alteration. Drillcore [Formula: see text]-ray measurements also indicate high potassium concentrations related to the K-rich phyllosilicates in the form of argillic and quartz-sericite alteration assemblages. Magnetization vector inversion (MVI) is used to recover an unconstrained 3D magnetization vector model of the system on regional and deposit scales. The regional MVI has resolved a deep concentric-shaped low magnetic zone that is interpreted as a porphyry system beneath the epithermal deposit. At the deposit scale, 3D direct current (DC) resistivity and induced polarization (IP) inversion, and unconstrained MVI revealed finer details of the epithermal system architecture. Cooperative DC/IP and magnetic inversion, at the deposit scale, constrained the magnetic susceptibility model and recovered a more precise susceptibility image of the epithermal system that is well-matched with borehole geology. The integrated geophysical interpretation helped to resolve several 3D latent geologic features in places without direct access to drillcore samples. We identified four petrophysical domains based on the three cooperatively inverted physical properties, including electrical resistivity, IP chargeability, and magnetic susceptibility. The combined geophysical models differentiated porphyritic intrusions (chargeability/susceptibility lows), disseminated sulfides (resistivity lows and chargeability highs), a Cu-rich zone in mafic volcanic rocks (susceptibility/chargeability highs and resistivity lows), and an Au-Ag-Cu-rich zone with silicification in felsic volcanic rocks (chargeability/susceptibility lows and resistivity highs). These petrophysical domains also provide useful exploration vectors for identification of similar epithermal systems.
Hepatic Steatosis Is Associated With Adverse Molecular Signatures in Subjects Without Diabetes
Authors: Pietzner Maik , Budde Kathrin , Homuth Georg , Kastenmüller Gabi , Henning Ann-Kristin , Artati Anna , Krumsiek Jan , Völzke Henry , Adamski Jerzy , Lerch Markus M , Kühn Jens P , Nauck Matthias , Friedrich Nele
Published: July 2018

Background and Aims

Exaggerated hepatic triglyceride accumulation (i.e., hepatic steatosis) represents a strong risk factor for type 2 diabetes mellitus and cardiovascular disease. Despite the clear association of hepatic steatosis with impaired insulin signaling, the precise molecular mechanisms involved are still under debate. We combined data from several metabolomics techniques to gain a comprehensive picture of molecular alterations related to the presence of hepatic steatosis in a diabetes-free sample (N = 769) of the population-based Study of Health in Pomerania.

Methods

Liver fat content (LFC) was assessed using MRI. Metabolome measurements of plasma and urine samples were done by mass spectrometry and nuclear magnetic resonance spectroscopy. Linear regression analyses were used to detect significant associations with either LFC or markers of hepatic damage. Possible mediations through insulin resistance, hypertriglyceridemia, and inflammation were tested. A predictive molecular signature of hepatic steatosis was established using regularized logistic regression.

Results

The LFC-associated atherogenic lipid profile, tightly connected to shifts in the phospholipid content, and a prediabetic amino acid cluster were mediated by insulin resistance. Molecular surrogates of oxidative stress and multiple associations with urine metabolites (e.g., indicating altered cortisol metabolism or phase II detoxification products) were unaffected in mediation analyses. Incorporation of urine metabolites slightly improved classification of hepatic steatosis.

Conclusions

Comprehensive metabolic profiling allowed us to reveal molecular patterns accompanying hepatic steatosis independent of the known hallmarks. Novel biomarkers from urine (e.g., cortisol glucuronide) are worthwhile for follow-up in patients suffering from more severe liver impairment compared with our merely healthy population-based sample.
Primary Hyperparathyroidism
Authors: Bilezikian John P
Published: July 2018

Background

Primary hyperparathyroidism (PHPT), the most common cause of hypercalcemia, is most often identified in postmenopausal women. The clinical presentation of PHPT has evolved over the past 40 years to include three distinct clinical phenotypes, each of which has been studied in detail and has led to evolving concepts about target organ involvement, natural history, and management.

Methods

In the present review, I provide an evidence-based summary of this disorder as it has been studied worldwide, citing key concepts and data that have helped to shape our concepts about this disease.

Results

PHPT is now recognized to include three clinical phenotypes: overt target organ involvement, mild asymptomatic hypercalcemia, and high PTH levels with persistently normal albumin-corrected and ionized serum calcium values. The factors that determine which of these clinical presentations is more likely to predominate in a given country include the extent to which biochemical screening is used, vitamin D deficiency is present, and whether parathyroid hormone levels are routinely measured in the evaluation of low bone density or frank osteoporosis. Guidelines for parathyroidectomy apply to all three clinical forms of the disease. If surgical guidelines are not met, parathyroidectomy can also be an appropriate option if no medical contraindications are present. If either the serum calcium or bone mineral density is of concern and surgery is not an option, pharmacological approaches are available and effective.

Conclusions

Advances in our knowledge of PHPT have guided new concepts in diagnosis and management.
A Misguided Contraindication: International Normalized Ratio in Acute Liver Failure Precluding Thrombolysis for Massive Pulmonary Embolism: A Case Report
Authors: Long Micah T. , Gallo Paul D. , Hammel Laura L. , Coursin Douglas B.
Published: July 2018

Massive pulmonary embolism and its treatment with thrombolysis both carry grave risks. Optimal management hinges on determining the risk-to-benefit ratio of thrombolytic administration. For patients with liver dysfunction, assessing bleeding risk is challenging because they may have elevations in the international normalized ratio yet be hypercoagulable. We describe a patient with massive pulmonary embolism and new-onset liver failure, who—absent contraindications—warranted thrombolysis. Initial laboratory values, however, revealed an elevated international normalized ratio, which precluded lysis, despite a hypercoagulable Thromboelastogram. We believe that viscoelastic testing of coagulation is essential for evaluating coagulation in liver dysfunction, particularly when considering thrombolysis.
Connexin 43 K63-polyubiquitylation on lysines 264 and 303 regulates gap junction internalization
Authors: Kells-Andrews Rachael M. , Margraf Rachel A. , Fisher Charles G. , Falk Matthias M.
Published: July 2018

Gap junctions (GJs) assembled from connexin (Cx) proteins allow direct cell–cell communication. While phosphorylation is known to regulate multiple GJ functions, much less is known about the role of ubiquitin in these processes. Using ubiquitylation-type-specific antibodies and Cx43 lysine-to-arginine mutants we show that ∼8% of a GJ, localized in central plaque domains, is K63-polyubiquitylated on K264 and K303. Levels and localization of ubiquitylation correlated well with: (1) the short turnover rate of Cxs and GJs; (2) removal of older channels from the plaque center; and (3) the fact that not all Cxs in an internalizing GJ channel need to be ubiquitylated. Connexins mutated at these two sites assembled significantly larger GJs, exhibited much longer protein half-lives and were internalization impaired. Interestingly, these ubiquitin-deficient Cx43 mutants accumulated as hyper-phosphorylated polypeptides in the plasma membrane, suggesting that K63-polyubiquitylation is triggered by phosphorylation. Phospho-specific anti-Cx43 antibodies revealed that upregulated phosphorylation affected serines 368, 279/282 and 255, which are well-known regulatory PKC and MAPK sites. Together, these novel findings suggest that the internalizing portion of channels in a GJ is K63-polyubiquitylated, ubiquitylation is critical for GJ internalization and that phosphorylation induces Cx K63-polyubiquitylation.

This article has an associated First Person interview with the first author of the paper.
Cell-matrix adhesion controls Golgi organization and function through Arf1 activation in anchorage-dependent cells
Authors: Singh Vibha , Erady Chaitanya , Balasubramanian Nagaraj
Published: July 2018

Cell-matrix adhesion regulates membrane trafficking controlling anchorage-dependent signaling. While a dynamic Golgi complex can contribute to this pathway, its regulation by adhesion remains unclear. Here we report that loss of adhesion dramatically disorganized the Golgi in mouse and human fibroblast cells. Golgi integrity is restored rapidly upon integrin-mediated re-adhesion to FN and is disrupted by integrin blocking antibody. In suspended cells, the cis, cis-medial and trans-Golgi networks differentially disorganize along the microtubule network but show no overlap with the ER, making this disorganization distinct from known Golgi fragmentation. This pathway is regulated by an adhesion-dependent reduction and recovery of Arf1 activation. Constitutively active Arf1 disrupts this regulation and prevents Golgi disorganization due to loss of adhesion. Adhesion-dependent Arf1 activation regulates its binding to the microtubule minus-end motor protein dynein to control Golgi reorganization, which is blocked by ciliobrevin. Adhesion-dependent Golgi organization controls its function, regulating cell surface glycosylation due to loss of adhesion, which is blocked by constitutively active Arf1. This study, hence, identified integrin-dependent cell-matrix adhesion to be a novel regulator of Arf1 activation, controlling Golgi organization and function in anchorage-dependent cells.

This article has an associated First Person interview with the first author of the paper.
Misfolding-prone proteins are reversibly sequestered to an Hsp42-associated granule upon chronological aging
Authors: Lee Hsin-Yi , Chao Jung-Chi , Cheng Kuo-Yu , Leu Jun-Yi
Published: July 2018

Alteration of protein localization is an important strategy for cells to regulate protein homeostasis upon environmental stresses. In the budding yeast Saccharomyces cerevisiae, many proteins relocalize and form cytosolic granules during chronological aging. However, the functions and exact components of these protein granules remain uncharacterized in most cases. In this study, we performed a genome-wide analysis of protein localization in stationary phase cells, leading to the discovery of 307 granule-forming proteins and the identification of new components in the Hsp42-stationary phase granule (Hsp42-SPG), P-bodies, Ret2 granules and actin bodies. We further characterized the Hsp42-SPG, which contains the largest number of protein components, including many molecular chaperones, metabolic enzymes and regulatory proteins. Formation of the Hsp42-SPG efficiently downregulates the activities of sequestered components, which can be differentially released from the granule based on environmental cues. We found a similar structure in the pre-whole genome duplication yeast species, Lachancea kluyveri, suggesting that the Hsp42-SPG is a common machinery allowing chronologically aged cells to contend with changing environments when available energy is limited.

This article has an associated First Person interview with the first author of the paper.
Multivariate Threshold Models: TVARs and TVECMs
Authors: Galvão Ana Beatriz C.
Published: July 2018

In this paper, I review recent developments on modelling macroeconomic variables with non-linear VARs. Specifically, the class of threshold VARs, including systems with threshold cointegration, is discussed. Techniques for specification, estimation, testing, computing impulse responses and forecasting are presented, including hints for practitioners. In addition, I analyze recent results on the evaluation of this class of models, providing guidance on the application of these models. Finally, a TVAR is applied to extract the information of the spread to predict recessions; and a TVECM is employed to test threshold cointegration in the context of the term structure of interest rates.
Exact Maximum Likelihood and Bayesian Estimation of the Stochastic Volatility Model
Authors: Motta Anderson C. O. , Hotta Luiz K.
Published: July 2018

This paper considers the classical and Bayesian approaches to the estimation of the stochastic volatility (SV) model. The estimation procedures rely heavily on the fact that SV model can be written in the State Space Form (SSF) with non-Ga ussian disturbances. The first widely employed estimation procedure to use this model was the quasi-maximum likelihood estimator proposed by Harvey et al. The Bayesian approach was proposed by Jacquier et al.(1994). Lately, many papers have appeared in the literature dealing with non-Gaussian state space models which directly influenced the estimation of the SV model. Some of these methods proposed to estimate the SV model are compared using the Sao Paulo stock exchange index (IBOVESPA) and simulated series. The influence of outliers is also considered.
Decomposition of Mehran and Piesch inequality measures by factor components and their application to the distribution of per capita household income in Brazil
Authors: Hoffmann Rodolfo
Published: July 2018

Inequality decomposition by factor components is extended to the Mehran and Piesch indices, comparing them with the decomposition of the Gini index, the squared coefficient of variation and the Theil's T coefficient. The decomposition procedure is applied to the distribution of per capita household income in Brazil in 1999, considering six components: earnings of civil servants and military personnel, earnings of other employees, earnings of self-employed workers, earnings of employers, pensions and, finally, all other incomes. One of the results is that for all the five measures used, the concentration ratio of pensions is higher than the overall index of inequality, indicating that this component is contributing to the increase in income inequality.
Generalized Hyperbolic Distributions and Brazilian Data
Authors: Fajardo José , Farias Aquiles
Published: July 2018

The aim of this paper is to discuss the use of the Generalized Hyperbolic Distributions to fit Brazilian assets returns. Selected subclasses are compared regarding goodness of fit statistics and distances. Empirical results show that these distributions fit data well. Then we show how to use these distributions in value at risk estimation and derivative price computation.
Evaluating the Forecasting Performance of GARCH Models Using White’s Reality Check
Authors: Souza Leonardo , Veiga Alvaro , Medeiros Marcelo C.
Published: July 2018

The important issue of forecasting volatilities brings the difficult task of back-testing the forecasting performance. As volatility cannot be observed directly, one has to use an observable proxy for volatility or a utility function to assess the prediction quality. This kind of procedure can easily lead to poor assessment. The goal of this paper is to compare different volatility models and different performance measures using White’s Reality Check. The Reality Check consists of a non-parametric test that checks if any of a number of concurrent methods yields forecasts significantly better than a given benchmark method. For this purpose, a Monte Carlo simulation is carried out with four different processes, one of them a Gaussian white noise and the others following GARCH specifications. Two benchmark methods are used: the naive (predicting the out-of-sample volatility by in-sample variance) and the Riskmetrics method
A Note on the Relation Between Principal Components and Dynamic Factors in Affine Term Structure Models
Authors: Almeida Caio Ibsen Rodrigues de
Published: July 2018

In econometric applications of the term structure, affine models are among the most used ones. Nevertheless, even presenting a closed form characteristic function, its estimation procedure still presents many points to be understood and difficulties to be removed. In this note, we address one of these points. Suppose we estimate an affine dynamic term structure model, and also apply principal component analysis to the interest rate database available. A very plausible question would inquire about the relation (if any) between the principal components obtained assuming no dynamic restrictions, and the dynamic factors estimated using the proposed term structure model. We answer this question when estimating a standard affine model using zero coupon data. We show that each principal component can be approximated by a linear transformation of the dynamic factors. Although simple, this is an important step to the understanding of the mechanics of dynamic affine term structure models. A numerical example using U.S. zero data illustrates the result
Further Results on Weak Exogeneity in Vector Error Correction Models
Authors: Rault Christophe
Published: July 2018

This paper extends the result for non-causality and strong exogeneity of Pradel and Rault and Pradel (2003) Exogeneity in VAR-ECM models with purely exogenous long-run paths, Oxford Bulletin of Economics and Statistics to weak exogeneity. More precisely, it provides a necessary and sufficient condition for weak exogeneity in vector error correction models. An interesting property is that the statistics involved in the sequential procedure for testing this condition are distributed as χ2 variables and can therefore be easily calculated with usual statistical computer packages, which makes our approach fully operational empirically
The alogenide minerals atacamite, iodargyrite in the epithermal gold mineralization of Profitis Ilias Milos island and their importance
Authors: ΔΗΜΟΥ Ε.
Published: July 2018

The present work refers to the mineralogical study of samples from borehole cores drilled in Profitis Ilias area at Milos island by the company "MIDAS" S.A., subsidiary of "Silver& Baryte Ores Mining Co" S.A., within the frames of the exploration for epithermal gold and silver. Intensely hydrothermally altered pyroclastic rocks of rhyodacitic composition occur in the area, transformed in a group of secondary minerals as alunite, jarosite, dickite, kaolinite, chrystobalite, chalcedony, adularla, quartz. Several quartz veins rich in barite and occasionally alunite traverse these rocks. The mineralization, located mainly into the quartz veins, is poor in metallic mineral proportion and consists of a few grains of hematite, pyrite, galena, chalcopyrite, bornite, chalcocine, tetraedrite, native gold, electrum, copper. Gold and silver of the order of 20ppm and 1300ppm respectively were observed in some core samples from boreholes of small depth (from 18 up to 21 m.). Initially, the exploration has been focused on the research for silver bearing minerals, taking also into consideration that high silver grades could not be explained by the restricted presence of electrum. However, the investigation proved that the high silver proportion derives from two rare silver alogenides minerals, Iodargyrite (Agi) and Chlorargyrite (AgCl), located into the cavities of the quartz veins or into fully altered-eroded voids of host rocks. These two alogenides present similar mineralogical properties and thus their identification was based mainly on the microanalyses. Moreover, Atakamite Cu2(OH)3Cl another alogenide mineral of emerald-green colour, has been found into the same samples. Its presence indicated increased grades in copper, since the metallic minerals of copper are almost absent. The presence of these alogenide minerals exclusively into cavities and the significant presence of alogene element iodine, suggest deposition, where the seawater (mixed or not with hydrothermal solutions) has played an important role. After the seawater intrusion into various formations (metamorphic basement, volcanic rocks) a high temperature are acquired, as well as enrichment in valuable metals (Au, Ag, Cu) which are deposited during its ascend in higher levels, mainly in form of alogenides. These rare alogenides display significant data on the general mineralization of the area and a different processing-recovery way of the valuable metals occurring into the epithermal mineralization.
Mineralogical composition and physical characteristics of marly soils from Heraklion Crete
Authors: ΤΣΙΡΑΜΠΙΔΗΣ Α. , ΠΑΠΑΛΙΑΓΚΑΣ Θ.
Published: July 2018

The mainly white-yellow marly soils studied present medium degree of consolidation and induration. The predominant grain size of the non - carbonate constituents is that of silt varying from 34 to 64%. According to the textural classification of soils of the SSDS the samples are mainly silty-clay loams with moisture capacity 30-40%. In the untreated samples in decreasing abundance the following minerals predominate: calcite (31-59%), clay minerals (20-34%) and quartz (12-20%). In the clay fraction (<2μπι) in decreasing abundance the following clay minerals (in discrete and interstratified phases) predominate: illite, smectite and vermiculite. Chlorite and kaolinite are missing. Mineralogically the marly soils are immature, because of the extended presence of Fe-Mg minerals (i.e. amphiboles, pyroxenes and clay minerals). According to the Unified Soil Classification System of the ASTM the studied marly soils mainly belong to the groups MH and CH (inorganic silts and inorganic clays respectively with high plasticity and liquid limit >50%), as well as to the group CL (inorganic clays with low plasticity and liquid limit <50%). The degree of consolidation and induration, as well as of compaction of these soils is medium. They contain significant amounts of discrete or interstratified smectite and mainly present high to very high swelling potential and activity between 0.5 and 2.0. It is concluded that specific precautions must be taken into account, when it is unavoidable the foundation of various constructions on these marly soils, because they swell and shrink extensively.
Kaolinization processes in the phyolitic rocks of Kefalos, Kos island, Aegean Sea, Greece
Authors: PAPOULIS D. , TSOLIS - KATAGAS P.
Published: July 2018

Kaolin occurrences in the South Kefalos peninsula, Kos island, Aegean sea, Greece, are products of hydrothermal alteration of rocks of rhyolitic composition. The chemical, mineralogical and textural characteristics of kaolin occurrences were investigated by X-Ray diffraction (XRD), Analytical scanning electron microscopy (SEM) and bulk rock chemical analyses. Attempts have been made to correlate the primary with secondary mineral assemblages and to establish the factors controlling the stepwise character of the transition from the fresh rhyolitic to kaolinized rocks. The kaolinization processes follows two main alteration pathways: I) Kfeldspar —» Mixed-layer kaolinite-smectite —» kaolinite —> dickite. II) Na-plagioclase —> kaolinite —> dickite
Kaolin deposits of Leucogia, Rhodope, Greece: Processes of Kaolinization
Authors: PAPOULIS D. , TSOLIS - KATAGAS P.
Published: July 2018

Kaolin deposits of residual origin associated with metamorphic rocks (leucocratic gneisses and schistgneisses) occur in Leucogia area, NE Greece. The chemical, mineralogical and textural characteristics of kaolin deposits were investigated by X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and chemical analyses. Attempts have been made to correlate the primary and secondary assemblages and to establish the factors controlling the step-wise character of the transition from the fresh gneisses to kaolinized rocks. The kaolinization process seems to follow two alteration pathways: (i) Sodic plagioclases ? Halloysite ? Kaolinite. (ii) K-Feldspars ? Kaolinite.
X-Ray powder diffraction of mineralogical samples by X-Ray goebel mirrors
Authors: PERDIKATSIS V. , PSYCHARIS V.
Published: July 2018

Comparative studies are presented on a series of standard and mineralogical samples with X-ray powder diffraction methods, which have been made with a diffractometer possessing the traditional Bragg-Brentano geometry and a second one equipped with a parabolic Goebel mirror (parallel optics). The diffractometers with the Bragg-Brentano geometry are used extensively for the analysis of polycrystalline samples, the main drawback of which is the high expertise needed by the user in order to maintain an instrument in perfect alignment and the careful preparation of the studied samples. Samples measured with a Goebel mirror in parallel optics are free from displacement errors caused by the displacement of the surface or by the surface roughness of the samples. The advantages of the parallel optics are valuable in the case of study of mineralogical samples with the same structure and variable chemical composition (feldspars, amphiboles, pyroxenes, clays etc.) or samples with irregular shapes. Another advantage of Goebel mirrors is the high intensity.
Indications for ultra-high pressure metamorphism of amphibolite xenolith in the Arnea granite
Authors: ΙΩΑΝΝΙΔΗΣ Ν. , ΣΚΛΑΒΟΥΝΟΣ Σ.
Published: July 2018

In this paper an amphibolite rock presented as xenolith into the Arnea granite close to Marathousa village has been examined. In particular, the xenolith is exposed into the aplitic granite portion of the Arnea granite at its contact with the Serbomacedonian massif. Microscopic studies and chemical analyses carried out in samples from the amphibolite xenolith and its contact zone with the aplitic granite has indicated the existence of tetrahedral and octahedral forms of "graphitized diamonds". This denotes that the amphibolite xenolith is the retrograde metamorphic rock of a previously, possibly eclogite rock, which the later was metamorphosed at least under ultra-high pressure metamorphic conditions. Mineral parageneses of the xenolith, as well as the use of the geobarothermometric methods have shown that the xenolith has been subjected to at least three metamorphic events. The first was attributed to a ultra-high pressure of at least 30-35kb, the second to a P-T conditions corresponding to 15kb and about 670 °C and the latest to 8.4 ± 1,2 kb and 380 ± 34 °C. The latest greenschist metamorphic event is the only metamorphic one imprinted in the Arnea granite. Taking account the latest dating of the Arnea granite crystallization age in Late Triassic (215 ± 1,8 Ma), we suggest that the examined xenolith was probably a part of a sedimentary crustal rock that metamorphosed to ultra-high pressure conditions associated with a deep subduction zone in the Late Paleozoic times. During Triassic it was retrograde metamorphosed to the amphibolitic metamorphic phase probably associated with a general uplifting of the area and finally it ascended as xenolith along with the Arnea granite to more shallow depths where they both subjected to the greenschist metamorphic event.
The Polychnitos ignimbrite of Lesvos island
Authors: LAMERA S. , SEYMOUR K. ST. , VAMVOUKAKIS C. , KOULl M. , PARASKEVAS E. , PE-PIPER G.
Published: July 2018

Miocene volcanism on Lesvos was particularly explosive giving rise to two extensive pyroclastic formations, the Sigri pyroclastics to the west and the Polychnitos ignimbrite to the east of the island. The Polychnitos ignimbrite at 17.2±0.5 Ma (Borsi et al.1972) is part of the shoshonitic succession on Lesbos which ranges in composition from basalt to rhyolite and is both underlain and overlain by calcalkaline volcanic rocks (Pe-Piper and Piper 1993) resting on a late Paleozoic metamorphic basement which has acted as an impediment to the free flow of the ignimbrite. The Polychnitos ignimbrite consists of eight lithological units, six of which are presumed to be facies of the same ignimbrite sheet ("PK", "PU", "MGF I, II, III", "Z"). Ignimbrite deposition at elevated temperatures is advocated by its columnar jointing, eutaxitic texture, gas escape structures and glassy zones of intense welding. The typical mineral assemblage of all Polychnitos ignimbrite units consists of plagioclase, Kfeldspar and biotite. It displays phenocryst microtextures indicative of magma mixing. Magma mixing is corroborated of glasses of two discrete compositions. Lithic clast measurements indicate a northeasterly trending fissure vent passing from the northeastern corner of the Kalloni Gulf.
Fluid inclusion thermometric and stable isotope (δ180-δD) evidence for "cryptic boiling" in the Profitis Ilias epithermal gold deposit, Milos: a potential exploration tool for epithermal gold
Authors: KILIAS S. P. , NADEN J. , LENG M. , CHELIOTIS I.
Published: July 2018

"Cryptic boiling" has been disclosed throughout the vertical extent of the Profitis Ilias epithermal system ('450 m) by assessing systematic variations in fluid inclusion and stable isotope (δ180-δD)data in relation to elevation. Highest gold grades (Au: 2-57.9 g/t) are preferentially concentrated in the upper 200-250 m of the system in a "steam-dominated zone" that is separated from a lower "liquid-dominated zone" (Au < 2 g/t). This distribution of gold may be due to colloidal transport in a boiling epithermal system. The identification of the base of the "steam-dominated zone" using fluid inclusion and stable isotope data may potentially guide exploration drilling to depths with high-grade gold ore in productive epithermal systems.
Contribution of mineralogical sedimentological and geochemical characteristics of deltaic deposits in the 137Cs sediment concetration
Authors: ΜΑΡΓΑΡΙΤΗΣ Ι.
Published: July 2018

This parer provides a review of the factors governing 137Cs sorption in sediments. We have specially focused in the correlation between sorption and the sedimentological mineralogical and geochemical characteristics of the sediments. Literature conclusions in experimental as well as field studies on 137Cs sorption is that 137Cs is strongly correlated with the < 20μηι fraction of the sediment as well as illite content. Other clay minerals such as smectite, kaolinite and chlorite sorb 137Cs in a lesser degree. Furthermore organic material and Fe-Mn hydroxides, act like sorptive surfaces. Our data on 137Cs activity variation based on field studies from deltaic deposits (Arachthos delta, Amvrakikos gulf, Greece)is also discussed. The results of this studies confirm the above mentioned, since 137Cs activity is strongly correlated with the clay fraction and the illite content,while a lesser correlation is indicated for total organic carbon Fe and Mn content of the sediments.
Evaluation of an Upper Cretaceous limestone from the area of Arta for lime production
Authors: CHRISTIDIS G. , TRIANTAFYLLOU G. , MARKOPOULOS T.
Published: July 2018

Calcination of an Upper Cretaceous limestone from the Ionian Unit at 700-1100°C for 1-4 hours yielded very reactive lime end products. Lime formation was monitored by means of kinetic curves and TTT diagrams. Particle size seems to control the onset of lime crystallization at low temperatures, but is of minor importance at higher temperatures. With the experimental setting used, lime formation was completed at 900 °C. The specific surface area of the end products increases with firing temperature up to 800 °C, decreasing thereafter. Decrepitation of lime increases gradually with firing temperature. Hydration temperature during slaking increases rapidly up to 900 °C being relatively constant thereafter. Sintering and production of fines during firing control the physical properties of lime.
Forming conditions of the Graikas lignite, N. Peloponnese
Authors: ΚΑΛΑΪΤΖΙΔΗΣ Σ. , ΠΑΠΑΖΗΣΙΜΟΥ Σ. , ΧΡΗΣΤΑΝΗΣ Κ.
Published: July 2018

In Northern Péloponnèse (southern Greece) several lignite seams occur, many of which were exploited in the past decades. In the small Graikas basin, in the upland Aigialia, a 2.5-m-thick lignite seam outcrops within the Pliocene/ Pleistocene sediments. The pre-Neogene margins and the basement of the basin consist of radiolarites, pelagic limestones, and flysch of the Pindos isopic zone. The sediments filling the basin include marly, sandy and clay layers, which deposited under marine, brackish and lacustrine conditions, during the rifting of the Corinth graben (Late Pliocene-Early Pleistocene). The seam consists of lignite and clay-rich lignite layers, of matrix lithotype, with total thickness of 1.4 m, intercalating with thin marly, silty, clay and humic clay layers. Fourteen lignite samples were obtained for proximate and ultimate analyses and coal-petrography studies. The ash contents of the Graikas lignite range up to 46.2% on dry base revealing intense inorganic input. The total sulphur contents are also high up to 4%. The fixed carbon and volatile matter contents (33.2-46% and 53.9-66.8% on daf, respectively), as well as the H/C and O/C atomic ratios and the reflectance of Eu-ulminite Β (Rm 0.26-0.30%), indicate a low rank (soft brown coal, Weichbraunkohle). Micropetrographic studies revealed a Huminite content >73%, Liptinite <23%, and Inertinite <12%. Attrinite and Densinite are the most prevailing macérais, while Texto-ulminite A and Eu-ulminite A show moderate values. Inertodetrinite and Semi-fusinite dominate within the Inertinite macerai group. Cutinite and Liptodetrinite are the most abundant macérais of the Liptinite group. Mainly clay and carbonate minerals constitute the inorganic matter (7-30%). However, pyrite content is also significantly high, up to 10%, revealing anoxic marine influence. Factor analysis suggests that peat accumulation started under anoxic conditions and intense bacterial activity. The peat-forming vegetation was mostly herbaceous with minor contribution of arboreal vegetation. Moreover, negative correlation is revealed between the gelification degree and the inorganic input. Coal-facies diagrammes suggest low preservation of the organic tissues and highly scattered gelificationindeces. The peat in the Graikas basin started accumulating in a lagoonal environment under brackish conditions behind a barrier. Progressively, sea regraded and the conditions became limnic to limnotelmatic
The distribution of the trace element contents in lignite and ash from Drama lignite deposit, using multivariate statistical analysis
Authors: PANILAS S. , HATZIYANNIS G.
Published: July 2018

Multivariate statistical analysis was used on existing geochemical data of the Drama lignite deposit, eastern Macedonia, Greece. Factor analysis with varimax rotation technique was applied to study the distribution of major, trace and rare earth elements in the lignite and 850°C lignitic ash, to find a small set of factors that could explain most of the geochemical variability. The study showed that major elements AI, Na, Κ, contained in the lignite samples, presented high correlation with most of the trace and rare earth elements. In 850°C lignitic ashes major and trace elements present different redistribution. Only Al remained correlated with the trace elements Co, Cr, Rb, Ta, Th, Ti, Sc and rare earths related with inorganic matter in the lignite beds. Trace elements Fe, Mo, U, V, W, and Lu were associated with organic matter of lignite and had also been affected by the depositional environment.
Hydrocarbon gas accumulations in Greece and their origin
Authors: RIGAKIS N. , ROUSSOS N. , KAMBERIS E. , PROEDROU P.
Published: July 2018

In the sedimentary basins of Greece are found a lot of hydrocarbon gases that can be distinguished in four categories. Surface gas seeps, gas shows in shallow water-wells, gases in exploration wells and hydrocarbon gas fields. The main gas shows are mainly located inside recent clastic sediments. Hydrocarbon amount varies between a few ppm and several units percent. Gases are classified in the biogenic gases of Katakolo onshore gas-field, the most surface gas seeps and the gases at shallow depths of exploration wells. Catagenetic are the gases of Katakolo oil field, the Epanomi and South Kavala gas fields, and a lot of gases found in great depths of exploration wells. Metagenetic gases have been identified in Delta Evros and West Thermaikos.
Innovation environment of large Russian companies: search for mechanisms of interaction
Authors: Веселитская Наталия , Veselitskaya Nataliya
Published: July 2018

The monograph explores the innovation environment of a large Russian company and mechanisms of interaction with it within the framework of new institutional economic theory.
This paper proposes an approach that enable large Russian companies to choose mechanisms suitable for such an interaction. This approach is based on the use of a logical scheme for selecting the mechanisms of interaction between the company and the innovation environment, applicable for solving problems of managing innovation at different stages of the life cycle.
Technical Note—Perishable Inventory Systems: Convexity Results for Base-Stock Policies and Learning Algorithms Under Censored Demand
Authors: Zhang Huanan , Chao Xiuli , Shi Cong
Published: July 2018

We develop the first nonparametric learning algorithm for periodic-review perishable inventory systems. In contrast to the classical perishable inventory literature, we assume that the firm does not know the demand distribution a priori and makes replenishment decisions in each period based only on the past sales (censored demand) data. It is well known that even with complete information about the demand distribution a priori, the optimal policy for this problem does not possess a simple structure. Motivated by the studies in the literature showing that base-stock policies perform near optimal in these systems, we focus on finding the best base-stock policy. We first establish a convexity result, showing that the total holding, lost sales and outdating cost is convex in the base-stock level. Then, we develop a nonparametric learning algorithm that generates a sequence of order-up-to levels whose running average cost converges to the cost of the optimal base-stock policy. We establish a square-root convergence rate of the proposed algorithm, which is the best possible. Our algorithm and analyses require a novel method for computing a valid cycle subgradient and the construction of a bridging problem, which significantly departs from previous studies.

The e-companion is available at https://doi.org/10.1287/opre.2018.1724