bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Heat Treatment on Microstructure and Mechanical Properties of As-Forged ZYK530 Mg Alloy
Authors: Cao Feng Hong , Chang Chen , Xu Yao Hui
Published: April 2020

In the paper, the microstructure and mechanical properties of ZYK530 Mg alloy with different aging heat treatment processes were analyzed and studied by OM, SEM, EDS and XRD. The results show that after heat treatment at different temperatures and aging times, the hardness of the alloy first decreases, then increases in a wave-like manner, and then decreases in a wave-like manner after reaching its peak value. The optimum aging process of ZYK530 alloy is T5-220°C×5h, and the maximum hardness is 88.34HRE, which tensile strength, yield strength and elongation are 335MPa, 305MPa and 13.5% respectively. Compared with the untreated forged alloy, the mechanical properties are increased by 6.3%, 4.8% and 35%, which its fracture mechanism is mainly ductile-brittle mixed fracture.
Infrared Emissivity of La0.8Sr0.2MnO3 under 0.76-2.5 μm and 2.5-500 μm Radiation Fields
Authors: Shen Xing Mei , Dong Ya Dong , Wang Jian , Wu Xing Rong , Cao Fa Bin
Published: April 2020

La0.8Sr0.2MnO3 was prepared to investigate the infrared emissivity of the sample under 0.76-2.5 μm and 2.5-500 μm infrared fields. The sample exhibited characteristic peaks of rhombohedral perovskite structure at 298-318 K, and split of the main peak weakened with increasing temperature. Intensity of the ferromagnetic resonance peak enhanced with increasing temperature, and the peak was shifted toward high magnetic field. A weak paramagnetic resonance peak appeared at 318 K, indicating that ferromagnetic-paramagnetic transition was occurring. The temperature of the sample under 2.5-500 μm field was higher than that under 0.76-2.5 μm. The emissivity of the sample increased with radiation time under 2.5-500 μm, but it had no obvious changes at about 0.665 under 0.76-2.5 μm. The emissivities at the same temperature fields were higher than those under 0.76-2.5 μm and 2.5-500 μm fields, respectively. It suggested that 0.76-2.5 μm and 2.5-500 μm radiations had inhibition effect on emissivity of La0.8Sr0.2MnO3.
The Interlaminar Toughening Effect of Hybrid PES/E51 Films on Carbon Fiber/ Epoxy Composite
Authors: Cheng Chao , Zhang Hui , Sun Ze Yu , Liu Yong , Yu Mu Huo
Published: April 2020

In this study, E51 was appended as an additive to the PES casting solution and hybrid PES/E51 films with different E51 content were produced by phase inversion approach, applied as interleaves to improve the interlaminar fracture toughness of CF/EP composite laminates prepared by vacuum assistant resin infusion process (VARI). The time that the hybrid film dissloved into the epoxy resin depended on the content of E51 in the film, moreover, it was observed that Mode I fracture toughness of the hybrid film modified composite reduced with the addition of E51 compared with the pure PES film interleaved composite, however, the tensile properties showed the opposite tendency. The reason was the reduction in the thickness of the interlayer resin illustrated by cross-section morphologies of all types of laminates.
Study on the Effect of Cleaning Technology of Fresh Tea Leaves on the Quality of Green Tea
Authors: Chen Sheng Xiang , Luo Jin Long , Li Pin Wu , Zhang Xun , Ao Cheng Wei , Li Jian Hua
Published: April 2020

This experiment was conducted to study the new shoot, bud and leaf of Fuding Dabai Tea, which was picked and purchased from Zhongfeng Tea Garden in Ya'an famous mountain area. The sensory quality, contents, pesticide residues and heavy metals of fresh leaves and green tea were studied and compared. The total soluble solids content and turbidity of water samples before and after the cleaning process were determined. The results showed that: (1) the weighted total score of sensory evaluation of finished tea added with fresh leaf cleaning technology was 91.15, which was 2.45 points higher than that of the control (without fresh leaf cleaning), and increased by 2.76%. (2) Fresh leaf cleaning process can significantly reduce the content of tea polyphenols, caffeine and water extract, and the ratio of phenol to ammonia, but has no significant effect on the content of amino acid and soluble sugar. (3) The total soluble solids of Q 2 are 4.3 times as much as Q1, and the turbidity of Q2 is 37.2 times as much as Q1. Cleaning process of fresh leaves can significantly reduce the indexes of agricultural residues and heavy metals. In conclusion, the cleaning process of fresh tea leaves can improve the sensory quality of tea to a certain extent, significantly reduce the content of bitter and astringent substances in tea leaves, effectively clean the surface impurities of fresh tea leaves, reduce pesticide residues and heavy metal content.
Study on Mechanically Activated Dioscorea Fiber and Analysis of Activation Energy
Authors: Long Xiang Li , Li Yan Sheng , Liang Qing Yan , Chen Mei Lin , Gao Hong
Published: April 2020

Microtopography of fiber of Discorea nipponica Makino before and after mechanical activated by AGO-2 planetary mill was observed by SEM, and they changed the thick floccules to fine particles (D50 particle sizes were 10.18μm). Discorea fiber powder after mechanical activation had a narrow size distribution. According to XRD, the granularity and structures of discorea fiber with and without mechanical activation significantly differed, and the crystalline of discorea fiber was significantly converted into amorphous state after mechanical activation. On the basis of TG–DSC analysis, the activity of discorea fiber was enhanced, and certain internal energy were stored, and complete decomposition in advance. According to FT-IR, none of the functional groups of the mechanically activated discorea fiber disappeared, and no new functional groups appeared, which indicate that mechanical activation does not induce a chemical transformation of discorea fiber. According to the activation energy analysis, the thermal activation energy of dioscorea fiber after mechanical activation was18.49 kJ•mol, and the mechanical transfer activation energy was 56.06 kJ•mol, indicating that about 1/3 of the mechanical transfer activation energy was stored in the activated dioscorea fiber fine powder in the form of surface energy and internal energy.
RETRACTED: Effect of Calcium Chloride on Hydration Kinetics and Pore Structure of Hydrated Tricalcium Silicate
Authors: Li Qin Fei , Yang Wang , Chen Heng , Hou Peng Kun , Cheng Xin
Published: April 2020

Chemical admixtures are frequently used to regulate the setting and strength development of concrete materials. In this study, tricalcium silicate (C3S) was used as a model of the cement system, and the influence of calcium chloride, an extremely useful accelerator, on C3S hydration and the pore structure of hardened C3S paste were investigated by the combination of the techniques of differential scanning calorimetry (DSC) and the N2 adsorption (BET). The results indicated that the addition of calcium chloride would significantly shorten the pre-induction and induction periods and enhance the specific surface area and porosity of hardened C3S paste. However, the presence of CaCl2 has little effect on the pores, with a width ranging from 2.5 nm to 5 nm. DSC technique has an advantage of measuring continuously the process of C3S hydration by changes of free water in hydrated C3S.
Effects of Feedstocks and Laser Remelting on Microstructural Characteristics of ZrO2-7wt.%Y2O3 Thermal Barrier Coatings Prepared by Plasma Spraying
Authors: Wang Dong Sheng
Published: April 2020

Conventional and nanometer aggregate ZrO2-7wt.%Y2O3 ceramic powders taken as raw materials, plasma spraying and plasma spraying-laser remelting compound technology was used to prepare conventional and nanostructured thermal barrier coatings on the TiAl alloy surface. Effects of powder structure (feedstock) and laser remelting on organizational structure and phase of the coatings were analyzed using scanning electron microscope (SEM) and X-ray diffractometer (XRD). Results indicate that: conventional plasma sprayed ceramic coating presents typical lamellar stacking features; plasma sprayed nanostructured coating consists of fully melted region and partially melted region, presenting a two-phase structure. Under the comprehensive impacts of laser power, energy density, temperature field distribution in the laser action region, ceramic heat conductivity coefficient and coating thickness and other factors, the coating presents obvious lamellar structural features after laser remelting; the upper part is compact columnar crystal remelting region and the lower part is residual plasma spraying region. Due to toughening effect of residual nanoparticles in the remelting region of laser remelted nanostructured coating, grain-boundary strength is high and there are a considerable number of transgranular fractures, but the fractures in the remelting region of laser remelted conventional coating are basically intergranular fractures. Conventional plasma sprayed ceramic coating is mainly of tetragonal phase together with a small quantity of monoclinic phases, but nanometer plasma sprayed ceramic coating only has non-equilibrium tetragonal phases. After laser remelting, both conventional coating and nanometer coating mainly have non-equilibrium tetragonal phases with a small quantity of cubic phases.
Design and Numerical Simulation of High Strength Lightweight RPC Pole
Authors: Fu Fang Da , Wang Lu Liang , Zhao Hai Long , Bai Jun Feng , Zhou Xu Dong , Song Yi Feng
Published: April 2020

In this paper, finite element model of reactive powder concrete (RPC) pole was established by using finite element analysis software ABAQUS, and the strength of RPC pole was checked. The results of finite element analysis and theoretical calculation are compared to provide a basis for determining the parameters used in finite element modeling and revising the theoretical calculation formula.
Effect of Sol-Gel Film on the Corrosion Resistance of Low Carbon Steel Plate
Authors: Zhang Hua Yuan , Wang Can , Xue Bing , Luo Jing
Published: April 2020

To improve the corrosion resistance on Q235 low carbon steel, in this paper, tetraethyl orthosilicate (TEOS), N-dodecyl trimethoxysilane and γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) were used to make organic-inorganic hybrid sol-gel film. Cross cut test adhesion method, neutral salt spray test, electrochemical test and film protective efficiency were taken to value the corrosion resistance property. The corrosion topography was studied by optical microscope. In addition, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) curves and equivalent electric circuit fitting were used to analyze the corrosion mechanism. The cross cut adhesion of sol-gel film can reach 1 class and the protection class can attain 5 class after 72 hours neutral salt spray test. According to the potentiodynamic polarization curve analysis, the corrosion potential of sol-gel film coating sample after 0.5 hours immersion was -0.46 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.74×10-7 A·cm-2. The corrosion potential of bare Q235 low carbon steel plate after 0.5 hours immersion was -0.78 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.75×10-6 A·cm-2. The impedance value on 0.1 Hz (|Z|0.1Hz) (1.27×106 Ω·cm2) of sol-gel film coating sample was more than three orders of magnitude higher than the value of the low carbon steel plate. Even dipping in 3.5 wt. % NaCl for 72 hours, the |Z|0.1Hz value of sol-gel coating sample was still one order of magnitude higher than the low carbon steel plate with 0.5 hours immersion. Sol-gel film with excellent adhesion can significantly improve the corrosion resistance of low carbon steel plate. Sol-gel film can increase the protection efficiency of low carbon steel plate by 90%.
Evaluation of Aflatoxin M1 enrichment factor in different cow milk cheese hardness category
Authors: Pecorelli Ivan , Branciari Raffaella , Roila Rossana , Ranucci David , Bibi Rita , Van Asselt Mariska , Valiani Andrea
Published: April 2020

Aflatoxin M1 (AFM1) is a hepatocarcinogenic and genotoxic derivative of aflatoxin B1 excreted into milk after ingestion of feed contaminated by Aspergillus genus fungi. Because of the important role of dairy products, especially cow cheese, in the human diet, there is great concern about the presence of AFM1 in this food category. EC Regulation No. 1881/2006 establishes the importance of the enrichment factor (EF), an essential parameter that must be defined in order to evaluate the maximum level of the toxin in cheese aiming to ensure that cheese has been produced from compliant milk. The Italian Ministry of Health has established two provisional AFM1 EFs (5.5 and 3.0) to be applied to as many cheese categories (hard and soft), defined according to the moisture content on a fat free basis (MFFB) classification. Two experimental productions of Primosale and Fior di Latte cheese, both belonging to the soft cheese category, showed an EF of 4.1 and 2.9 respectively. Data in literature also suggest that the EF attribution based on the current categorization may need reconsideration.
Biogenic amines content in Fiore Sardo cheese in relation to free amino acids and physicochemical characteristics
Authors: Manca Gavina , Ru Antonio , Siddi Giuliana , Mocci Anna Maria , Murittu Gavino , De Santis Enrico Pietro Luigi
Published: April 2020

Fiore Sardo is a Protected Designation of Origin (PDO) cheese produced in Sardinia (Italy) from raw sheep’s milk, presenting risk factors due to an accumulation of Biogenic Amines (BA). A total of 37 Fiore Sardo cheese samples produced in 19 dairy farms were collected from local retail stores to evaluate BA content and its relationship with free amino acids (FAA) and composition. The following were determined for each sample: pH, water activity, composition (moisture, dry matter, NaCl, protein and fat content). FAA and BA, after extraction, were determined by HPLC-FL. The total BA content in Fiore Sardo PDO cheese samples was 127±87 mg 100 g-1, ranging between 6 and 366 mg 100 g-1. Tyramine showed the highest concentration (82±51 mg 100 g-1), followed by putrescine (21±26 mg 100 g-1). Moreover, cadaverine, histamine, β-phenylethylamine and tryptamine were detected at concentrations lower than 10 mg 100 g-1. Overall 54% of the samples analysed exceeded the threshold of 90 mg 100 g-1 for total BA content, posing a potential risk for consumers. BA, total FAA (2233±764 mg 100 g-1) and pH were positively correlated (P≤0.01) between themselves, whereas BA content was not correlated with aw, humidity and percentage of NaCl. The hierarchical cluster analysis results, considering 37 samples and 6 variables, detected four different groups. Samples with BA ≥200 mg 100 g-1 were distributed in two groups characterized by a higher proteolysis indicator levels (FAA, pH) but significantly different for aw, humidity and NaCl concentration. The results showed that high levels of BA were detectable in some samples of Fiore Sardo PDO cheese, suggesting that effective technological conditions at production should be adopted.
Phacotus lenticularis content in carbonate sediments and epilimnion in four German hard water lakes
Authors: Lenz Sebastian , Dubois Nathalie , Geist Juergen , Raeder Uta
Published: April 2020

Autochthonous calcite precipitation is an important process for C-fixation in hard-water lakes, which is mainly induced by the photosynthesis of planktonic microorganisms. Among these, the widespread calcifying green alga Phacotus lenticularis (Ehrenberg) Diesing contributes to biogenic calcite precipitation in temperate regions. Its role in carbonate precipitation needs to be investigated, because there are no studies dedicated to the quantitative contribution of Phacotus shells to long term carbonate sequestration in hard-water lake sediments. In order to fill this gap, the Phacotus shell content in the sediments of four German hard-water lakes was determined and compared to the fraction of Phacotus shells in the total suspended autochthonous calcite of the euphotic zone.It was found that the Phacotus shells contributed at least 10% to the autochthonous carbonate precipitation in the upper water column in three investigated lakes. During a Phacotus mass occurrence with a cell density of 1.8 × 106 Ind L-1 in Lake Hopfensee, even 59% of the 3.6 mg L-1 total carbonate concentration consisted of Phacotus shells. In contrast to this high amount, the topmost basinal sediment contained a Phacotus shell content between 80 and 36,252 individuals per mg dry sediment, representing only 0.02% to 2.28% of the total carbonate sediment content. In a gravity core from Lake Grosser Ostersee, dating back ~150 years, the Phacotus shell content was continuously below 0.24% whereas the shell diameters remained equal to those of living individuals found in the water column proving that Phacotus shells are capable to persist in the sediment after deposition.A main reason for the large discrepancy between Phacotus shell abundance in the euphotic zone and in sediment was found to be the gross authigenic carbonate precipitation, which dilutes the sedimenting Phacotus shells that accumulate exclusively during short and intensive population peaks in summer. Additionally, dissolution of the carbonate shells during sedimentation was proven to be a relevant factor in Lake Igelsbachsee by means of reducing the number of Phacotus shells reaching the lake bottom. These facts explain that short-term high Phacotus carbonate contents of the total suspended carbonate in the water column do not mirror the contribution of Phacotus shells in the sedimentary record.
Spinal reflex action
Authors: Buller A. J.
Published: April 2020

No abstract available.
Ante and postnatal prophylactic education reassessed
Authors: Harte Rosemary
Published: April 2020

No abstract available.
The diurnal cycle of the clouds extending above the tropical tropopause observed by spaceborne lidar
Authors: Dauhut Thibaut , Noel Vincent , Dion Iris-Amata
Published: April 2020

Abstract. The presence of clouds above the tropopause over tropical convection centers
has so far been documented by spaceborne instruments that are either
sun-synchronous or insensitive to thin cloud layers. Here we document, for
the first time through direct observation by spaceborne lidar, how the
tropical cloud fraction evolves above the tropopause throughout the day.
After confirming previous studies that found such clouds most frequently
above convection centers, we show that stratospheric clouds and their
vertical extent above the tropopause follow a diurnal rhythm linked to
convective activity. The diurnal cycle of the stratospheric clouds displays
two maxima: one in the early night (19:00–20:00 LT) and a later one (00:00–01:00 LT).
Stratospheric clouds extend up to 0.5–1 km above the tropopause during
nighttime, when they are the most frequent. The frequency and the vertical
extent of stratospheric clouds is very limited during daytime, and when
present they are found very close to the tropopause. Results are similar
over the major convection centers (Africa, South America and the Warm Pool), with
more clouds above land in DJF (December–January–February) and less above the ocean and in JJA (June–July–August).
Statistical downscaling with the downscaleR package (v3.1.0): contribution to the VALUE intercomparison experiment
Authors: Bedia Joaquín , Baño-Medina Jorge , Legasa Mikel N. , Iturbide Maialen , Manzanas Rodrigo , Herrera Sixto , Casanueva Ana , San-Martín Daniel , Cofiño Antonio S. , Gutiérrez José Manuel
Published: April 2020

Abstract. The increasing demand for high-resolution climate information has attracted growing attention to statistical downscaling (SDS) methods, due in part to their relative advantages and merits as compared to dynamical approaches (based on regional climate model simulations), such as their much lower computational cost and their fitness for purpose for many local-scale applications. As a result, a plethora of SDS methods is nowadays available to climate scientists, which has motivated recent efforts for their comprehensive evaluation, like the VALUE initiative (http://www.value-cost.eu, last access: 29 March 2020). The systematic intercomparison of a large number of SDS techniques undertaken in VALUE, many of them independently developed by different authors and modeling centers in a variety of languages/environments, has shown a compelling need for new tools allowing for their application within an integrated framework. In this regard, downscaleR is an R package for statistical downscaling of climate information which covers the most popular approaches (model output statistics – including the so-called “bias correction” methods – and perfect prognosis) and state-of-the-art techniques. It has been conceived to work primarily with daily data and can be used in the framework of both seasonal forecasting and climate change studies. Its full integration within the climate4R framework (Iturbide et al., 2019) makes possible the development of end-to-end downscaling applications, from data retrieval to model building, validation, and prediction, bringing to climate scientists and practitioners a unique comprehensive framework for SDS model development. In this article the main features of downscaleR are showcased through the replication of some of the results obtained in VALUE, placing an emphasis on the most technically complex stages of perfect-prognosis model calibration (predictor screening, cross-validation, and model selection) that are accomplished through simple commands allowing for extremely flexible model tuning, tailored to the needs of users requiring an easy interface for different levels of experimental complexity. As part of the open-source climate4R framework, downscaleR is freely available and the necessary data and R scripts to fully replicate the experiments included in this paper are also provided as a companion notebook.
The role of liquid water percolation representation in estimating snow water equivalent in a Mediterranean mountain region (Mount Lebanon)
Authors: Fayad Abbas , Gascoin Simon
Published: April 2020

Abstract. In many Mediterranean mountain regions, the seasonal
snowpack is an essential yet poorly known water resource. Here, we examine,
for the first time, the spatial distribution and evolution of the snow water
equivalent (SWE) during three snow seasons (2013–2016) in the coastal
mountains of Lebanon. We run SnowModel (Liston and Elder, 2006a), a
spatially distributed, process-based snow model, at 100 m resolution forced
by new automatic weather station (AWS) data in three snow-dominated basins
of Mount Lebanon. We evaluate a recent upgrade of the liquid water
percolation scheme in SnowModel, which was introduced to improve the
simulation of the SWE and runoff in warm maritime
regions. The model is evaluated against continuous snow depth and snow
albedo observations at the AWS, manual SWE measurements, and MODIS snow
cover area between 1200 and 3000 m a.s.l. The results show that the new
percolation scheme yields better performance, especially in terms of SWE but
also in snow depth and snow cover area. Over the simulation period between
2013 and 2016, the maximum snow mass was reached between December and March.
Peak mean SWE (above 1200 m a.s.l.) changed significantly from year to year
in the three study catchments, with values ranging between 73 and 286 mm w.e. (RMSE between 160 and 260 mm w.e.). We suggest that the major sources of
uncertainty in simulating the SWE, in this warm Mediterranean climate, can
be attributed to forcing error but also to our limited understanding of the
separation between rain and snow at lower-elevations, the transient snowmelt events during the accumulation season, and the high variability of snow
depth patterns at the subpixel scale due to the wind-driven blown-snow
redistribution into karstic features and sinkholes. Yet, the use of a
process-based snow model with minimal requirements for parameter estimation
provides a basis to simulate snow mass SWE in nonmonitored catchments and
characterize the contribution of snowmelt to the karstic groundwater
recharge in Lebanon. While this research focused on three basins in the
Mount Lebanon, it serves as a case study to highlight the importance of wet
snow processes to estimate SWE in Mediterranean mountain regions.
Can we trust remote sensing evapotranspiration products over Africa?
Authors: Weerasinghe Imeshi , Bastiaanssen Wim , Mul Marloes , Jia Li , van Griensven Ann
Published: April 2020

Abstract. Evapotranspiration (ET) is one of the most important components in the water cycle. However, there are relatively few direct measurements of ET available (e.g. using flux towers). Nevertheless, various disciplines, ranging from hydrology to agricultural and climate sciences, require information on the spatial and temporal distribution of ET at regional and global scales. Due to the limited data availability, attention has turned toward satellite-based products to fill observational gaps. Various data products, including remote sensing (RS) products, have been developed and provide a large range of ET estimations. Across Africa, only a limited number of flux towers are available; hence, they are insufficient for the systematic evaluation of the available ET products. Thus, in this study, we conduct a methodological evaluation of nine existing RS-derived ET products as well as other available ET products in order to evaluate their reliability at the basin scale. A general water balance (WB) approach is used, where ET is equal to precipitation minus discharge for long-term averages. Firstly, ET products are compared with WB-inferred ET (ETWB) for basins that do not show long-term trends. The ET products and the calculated ETWB are then evaluated against the Budyko equation, which is used as a reference condition. The spatial characteristics of the ET products are finally assessed via the analysis of selected land cover elements across Africa: forests, irrigated areas and water bodies. Additionally, a cluster analysis is conducted to identify similarities between individual ET products. The results show that CMRSET, SSEBop and WaPOR rank highest in terms of the estimation of the long-term average mean ET across basins, with low biases and good spatial variability across Africa. GLEAM consistently ranks lowest in most evaluation criteria, although it has the longest available time period. Each product shows specific advantages and disadvantages. Depending on the study in question, at least one product should be suitable for a particular requirement. The reader should bear in mind that many products suffer from a large bias. Based on the evaluation criteria in this study, the three highest ranked products, CMRSET, SSEBop and WaPOR, would suit many users' needs due to the low biases and good spatial variability across Africa.
Information at Work: Information Management in the Workplace
Authors: Farris David
Published: April 2020

This book is highly recommended to add to academic library collections, especially those supporting a university with a library and information science program.
Using the Lens database for staff publications
Authors: Penfold Rob
Published: April 2020

In a rapidly changing landscape, many health sciences libraries are looking to increase the support they provide for research in their organization. The Lens database is a free platform for enabling discovery of both scholarly and patent literature.
Claire Fraser, RN, MD, OMG: history of medicine in the Outlander novels and series
Authors: Greenberg Stephen J.
Published: April 2020

This article discusses how Claire Randall, RN, MD, the fictional protagonist of Diana Gabaldon’s widely popular Outlander series, uses her knowledge of twentieth century medicine in her adventures in eighteenth century Scotland, France, and America.
Nuevos desafíos en la Educación Superior: análisis de resultados obtenidos y dificultades experimentadas en la realización del Trabajo Fin de Grado de estudiantes de los Grados de Maestro de la Universidad de Salamanca
Authors: Vicario-Molina Isabel , Martín-Pastor Elena , Gómez-Gonçalves Alejandro , González Rodero Luis María
Published: April 2020

En la universidad española, el Trabajo Fin de Grado (TFG) es el último escalón en el periodo formativo de los estudiantes de grado, y desempeña una importante función en la evaluación de las competencias, conocimientos y aptitudes adquiridas. Esta asignatura supone un reto para los futuros graduados ya que deben hacer frente a diferentes dificultades durante su proceso de elaboración. La base de inicio de este trabajo se encuentra en el estudio de las variables que determinan estas dificultades, así como de aquellas que influyen en el resultado final del TFG. Por tanto, el objetivo de esta investigación es analizar los resultados obtenidos –nota y satisfacción- y las dificultades experimentadas por una muestra de alumnos universitarios durante la elaboración de su TFG. Para alcanzar el objetivo formulado, se contó con la participación de 251 estudiantes egresados de los Grados de Maestro (Infantil y Primaria) de la Universidad de Salamanca, a los que se administró un cuestionario online, elaborado ad hoc para el presente estudio, compuesto por 17 ítems. Los resultados desvelan que las principales dificultades experimentadas por los alumnos se concretan en el uso correcto de la normativa APA y en la compatibilidad del TFG con el desarrollo de otras actividades. Además, el nivel de satisfacción de los estudiantes con el trabajo realizado es inferior a la nota obtenida, siendo el papel que desempeña el tutor, uno de los principales factores predictivos de los resultados obtenidos. Este trabajo pretende complementar los estudios existentes sobre el TFG al profundizar en aquellos aspectos que más entorpecen su desarrollo desde la perspectiva del propio alumnado, así como las variables que más directamente se relacionan con el resultado final.
Entrevista a Elías José Palti sobre Arqueología de lo político y la multiplicidad de regímenes del poder
Authors: Editorial Equipo
Published: April 2020

Elías José Palti entrevistado por Aldo Ocampo González
“Like a Realtor in Peoria”: Patton Oswalt, Twitter, and Heckling as Social Activism
Authors: Kapica Steven S.
Published: April 2020

In late January of 2017, comedian and prolific Twitter user Patton Oswalt posted a satirical tweet about President Donald Trump's firing of acting Attorney General Sally Yates. Pro-Trump Illinois real estate agent Tony Brust heckled Oswalt in a response tweet, instigating a Twitter battle that resulted in Brust deleting his Twitter and Facebook accounts and losing his job. This article defines Oswalt's social media-based comedy as a rhetoric of agitation, suggesting his comedic tweets, characterized by features of heckling and trolling, work as the highly emotional appeals of agitational rhetoric. The incident with Oswalt and Brust enriches our understanding of internet trolling and heckling and reveals the uneven power dynamics at work in Twitter's participatory culture. The platform's facilitation of multiple, permeable publics allows comedy to be a vehicle for the unregulated advancement of social agendas, the policing of dissent, and ultimately the promotion of real world change.
Religiosity and Intention towards Saving of a Muslim Minority in Greece
Authors: Satsios Nikolaos , Hadjidakis Spyros , Sotiropoulos Ioannis , Tsounis Nicholas
Published: April 2020

Culture influences financial decisions of individuals therefore, by examining the cultural background of cultural differences stemming from difference in religious beliefs is of significance to better understand their preferences and financial decisions. This research examines the relation of religiosity and intention towards saving of Pomak households, a Muslim minority living in the northeaster part of Greece. Quantitative data, collected with field research using the Religious Commitment Inventory (RCI-10) and Warneryd’s saving intention scale was used. The results reveal that there is a strong relation between religiosity and intention towards saving, indicating that the intention to save is affected by the religious norms of a person.
Emergency Nurses Job Satisfaction Prediction Model: Personality traits, Resilience, Emotional Expression and Ambiguity Tolerance
Authors: Eghbali Sahar , Najafi Masoomeh
Published: April 2020

Background: Nursing is considered as one of the most stressful jobs due to the emotional nature of the patient's demands, long working hours, professionals and interpersonal conflicts.

Aim: The purpose of present research was the study of job satisfaction predictors consisted personality traits, resilience, emotional expression and ambiguity tolerance of emergency nurses in Tehran hospitals.

Methods: This is a descriptive and correlational study. The population includes all emergency nurses in all hospitals of Tehran in 2017. The sample size consisted of 300 nurses who were selected randomly. For data collection were used NEO Personality Inventory, Berkeley Emotional Expression Questionnaire (BEQ), Job Satisfaction Survey (JSS), Resilience Scale (RS) and Ambiguity Tolerance Scale (ATS).

Results: The results demonstrate that ambiguity tolerance, resilience and emotional expression respectively had respectively the highest impact on job satisfaction, but personality traits had the lowest impact on it.

Implications for Practice: Personality traits can be a predictor of the job satisfaction of emergency nurses in hospital environment.
The Effect of One Session Acute Exercise on the Urinary Excretion of Urinary Gamma-Glutamyl Transferase, Protein and Creatinine Levels of Elite Football Players
Authors: Azar Ramtin , Majidi Paria
Published: April 2020

The aim of the present study was to evaluate the effect of one session acute exercise on the urinary excretion of urinary Gamma-glutamyl transferase, protein and creatinine levels in elite football players. A total of 30 Premier League football players with a mean age (26.1±3.80), a mean height (180.01±7.39), a mean weight (78.6±9.26) and a mean body mass index (24.87±1.13) were voluntarily and purposefully selected as statistical samples. The urinary sample of the players was collected in two stages. In the first stage, the players' urinary samples were taken on the rest day when they had not exercised for 24 hours. In the second stage, it was taken immediately after exercise and transferred to the laboratory. To test the hypotheses, especially to compare urinary protein, creatinine, and gamma-glutamyl transferase levels before and after exercise, and to compare excretion levels of protein, creatinine, and gamma-glutamyl transferase between the positions, ANOVA test was used. There was a significant difference between the levels of gamma-glutamyl transferase, proteinuria and creatinine before and after exercise (P
The Effect of Copper Price Shock on the Relationship between Government Revenue and Expenditure: Testing the Fiscal Stability Law of Mongolia
Authors: Bayarsaikhan Ariungerel
Published: April 2020

This study empirically investigates the relationship between government revenue, government expenditure and the copper price in Mongolia, a resource abundant country. Using quarterly data of government revenue, expenditure and international copper price from 2000 to 2015, the results of auto regression (VAR) show that there is a strong causality from revenue to expenditure, while increase in expenditure, most likely, is not accompanied by rises in revenue. This result is consistent with the revenue-spent hypothesis. Moreover, the result also indicates that copper price shock increases revenue, but decreases expenditure. This finding supports the assumption that the Mongolian government follows its Fiscal Stability Law, a strategy that intends to maintain the stability and sustainability of the government budget.
Relationship Between Intrinsic/Extrinsic Motivation and L2 Speaking Skill Among Iranian Male and Female EFL Learners
Authors: Salehpour Gholamreza , Roohani Ali
Published: April 2020

This study investigated the relationship between intrinsic/extrinsic motivation and L2 (English) speaking skill between male and female high school students in Iranian EFL context. To this end, 249 male and female students’ intrinsic and extrinsic motivation was measured with a questionnaire and their English speaking skill was assessed by a speaking rating scale. To triangulate the data, semi-structured interviews with a sample of 25 EFL students were conducted. The results of descriptive statistics and correlation coefficients demonstrated that the females had a higher level of intrinsic motivation while the males had a higher level of extrinsic motivation. Besides, the degree of correlation between intrinsic motivation and attainment of L2 speaking skill was statistically higher among the females. Also, t-test results indicated a statistically significant difference in the intrinsic/extrinsic type of motivation between the male and female students. The findings highlight the role of gender in dealing with motivation in L2 classes.
Application methods of multidimensional comparative analysis to the assessment of environmental state in Dolnośląskie voivodship
Authors: Bąk Andrzej
Published: April 2020

The aim of this article is to present the results of multidimensional comparative analysis methods used to assess the state of the environment in Dolnośląskie voivodship in the cross-section of powiats. The research was conducted on the basis of data from the CSO of Poland for 2015 concerning the state and environmental protection in 30 powiats of Dolnośląskie voivodship. The method of linear ordering of objects based on a pattern object (or an anti- -pattern object) was used in the research. Many of them described in the subject literature usually lead to differing results (rankings of objects are not the same). It results from i.a. the adopted methods of normalization and weighing of variables and aggregations (creation of synthetic variables). The article is an attempt to compare the results of linear ordering of powiats due the environmental state with the use of method based on a pattern object (or an anti-pattern object). In the rankings correctness analysis, quality indicators were used to evaluate the quality of linear ordering methods.
Several Aspects of Nonparametric Prediction of Nonlinear Time Series
Authors: Orzeszko Witold
Published: April 2020

Nonparametric regression is an alternative to the parametric approach, which consists of applying parametric models, i.e. models of the certain functional form with a fixed number of parameters. As opposed to the parametric approach, nonparametric models have a general form, which can be approximated increasingly precisely when the sample size grows. Hereby they do not impose such restricted assumptions about the form of the modelling dependencies and in consequence, they are more flexible and let the data speak for themselves. That is why they are a promising tool for forecasting, especially in case of nonlinear time series. One of the most popular nonparametric regression method is the Nadaraya- Watson kernel smoothing. Nowadays, there are a number of variations of this method, like the local-linear kernel estimator, which combines the local linear approximation and the kernel estimator. In the paper a Monte Carlo study is conducted in order to assess the usefulness of the kernel smoothers to nonlinear time series forecasting and to compare them with the other techniques of forecasting.
The Effect of Nonmonetary Factors on the Demand for Insurance and Self-Insurance
Authors: Dudziński Piotr
Published: April 2020

The article considers the impact of nonmonetary factors (health) on insurance and self-insurance (against material damage) decisions. Using a two-argument utility function, we prove that the health deterioration leads to increased demand for insurance if the decision-maker is cross-prudent in health and if wealth and health are complements. Those conditions are equivalent to positivity of second and third order degree cross-derivatives of the utility function. Second part of the article considers analogous effect of health deterioration on self-insurance. In this case the result depends additionally on effectivity of self-insurance as a function of the state of the world.
Strong and Safe Nash Equilibrium in Some Repeated 3-Player Games
Authors: Kufel Tadeusz , Plaskacz Sławomir , Zwierzchowska Joanna
Published: April 2020

The paper examines an infinitely repeated 3-player extension of the Prisoner’s Dilemma game. We consider a 3-player game in the normal form with incomplete information, in which each player has two actions. We assume that the game is symmetric and repeated infinitely many times. At each stage, players make their choices knowing only the average payoffs from previous stages of all the players. A strategy of a player in the repeated game is a function defined on the convex hull of the set of payoffs. Our aim is to construct a strong Nash equilibrium in the repeated game, i.e. a strategy profile being resistant to deviations by coalitions. Constructed equilibrium strategies are safe, i.e. the non-deviating player payoff is not smaller than the equilibrium payoff in the stage game, and deviating players’ payoffs do not exceed the nondeviating player payoff more than by a positive constant which can be arbitrary small and chosen by the non-deviating player. Our construction is inspired by Smale’s good strategies described in Smale’s paper (1980), where the repeated Prisoner’s Dilemma was considered. In proofs we use arguments based on approachability and strong approachability type results.
Labour Market Areas in Poland
Authors: Ryczkowski Maciej , Ryczkowski Maciej , Stopiński Paweł
Published: April 2020

The aim of the article is to delineate Labour Market Areas (LMAs) in Poland with the use of the European version of the Travel to Work Areas (EU-TTWA) methodology that was developed under Eurostat auspices. We received over 300 areas that consist of LAU-2 units (gminas) – the smallest administrative regions in Poland. We discuss Poland-specific results and problems. We compare numbers of LMAs in countries with EU-TTWA-delineated LMAs in relation to population density, total population and area. We propose the taxonomic rank method to select the parameter values for the EU-TTWA algorithm. LMAs may deliver useful spatial information, although one needs to account for their heterogeneity.
Impact of Discretization Units on the Modelling Efficiency of Currency Exchange Rate in Binary Representation
Authors: Piasecki Krzysztof , Stasiak Michał Dominik
Published: April 2020

Exchange rate course trajectory can be visualised in a binary representation. Binarization algorithm involves transformation of a course represented by tic data into a respective binary string. Each exchange rate increase by one discretization unit is assigned a binary value 1, and a respective decrease is assigned a 0. Properties and character of the exchange rate course in binary representation, that is, for example, influence of random fluctuations (noise) or relationship between current changes and historical data, are dependent on the appointed discretization unit. In the article a statistical analysis of an exchange rate trajectory for AUD/NZD currency pair in binary representation with different discretization units is presented. The analysis was performed in order to verify possible application of binary representation to create prediction systems based on binary representation state model (BRSM). Data used in performed research consisted of tick data for AUD/NZD from a five-year time period 2012–2017.
Analysis of factors determining the reaction to a legal problem using a multinomial logit model
Authors: Florczak Waldemar , Grabowski Wojciech
Published: April 2020

The aim of the study is to identify and quantify the influence of factors determining the reaction to the occurrence of a legal problem. On the basis of literature review, a list of such factors was prepared and, subsequently, on the basis of data from the national survey conducted by the Institute of Public Affairs (IPA) in Warsaw in 2012, structural parameters of the multinomial logit model were estimated. The research presents that a decision on the legal problem depends primarily on the type of experienced issue, its importance, attitudes towards law and several other socio-economic features which influenced people. Moreover, the research outcomes show that reductions in demand for legal counselling caused by the low income are not significant, whereas, spatial availability appears to be a more important barrier.
(A)symmetrical supply and demand shocks in Central and Eastern European countries
Authors: Piłat Katarzyna
Published: April 2020

The aim of the paper is to examine the similarity of responses of the economies of Central and Eastern Europe countries to the shocks in euro area and response observed in the group of countries that adopted common currency. The study used time series of quarterly GDP values and inflation rate. Data were extracted from the Eurostat database for the period from 1st quarter 1998 to 1st quarter 2014. The methodology of the research was based on a structural model of vector autoregression (SVAR) and shock decomposition was carried out using the Blanchard and Quah approach. The results obtained show a relatively strong correlation between the responses of the examined countries and the euro area to demand disturbances, with the highest coefficients for the Czech Republic and Poland. In the case of supply shocks, the correlation coefficients achieved a lower level, while the best adjustment of the response to the euro area disturbances was observed in Poland and Hungary.
Economic determinants of intervoivodship migration
Authors: Szczepaniak Daniela , Tokarski Tomasz
Published: April 2020

The aim of the research is to indicate the influence of economic determinants of interregional migration flows in Poland in the years 1999—2015. The analysis was conducted on the basis of data from the Local Data Bank of Statistics Poland using descriptive methods of migration flows differentiation analysis, wages and unemployment rates in time and space and spatial econometrics methods: the least squares method (LSM), generalised method of moments (GMM), logistic models and fixed effects models.
The conclusions of the research are as follows: migration inflows are most strongly influenced by relative wages, and outflows by the relative unemployment rate. Moreover, migrants decide to change their place of residence, taking into account a spatial factor.
Use of information and communication technologies in enterprises in voivodship terms
Authors: Becker Aneta
Published: April 2020

The aim of the article is a multi-criteria analysis of voivodships with regard to the use of information and communication technologies (ICT) by enterprises in 2015.The ANP method, which is classified as one of multi-criteria decision-making methods, was used in the research. Expert knowledge of ICT specialists employed in enterprises participating in the survey of Statistics Poland was applied. On this basis, ICT attributes were selected and a criterion structure was constructed. In the case of main criteria, preferences were determined considering strengths and weaknesses of voivodships. As a result of the k-means method classification, groups of voivodships were established due to the use of ICT by enterprises. Preferences in the case of sub-criteria were based on the principle that the criteria characterizing the latest trends of ICT development are of the highest importance.
The obtained results can be applied to evaluate the ICT space and the degree of enterprises involvement in modern technologies usage by voivodships.