bluuebunny/crossref_metadata_2025 huggingface dataset:
The E-Learning on Analysis of the Experimental Results by Using Graphs
Authors: Sirathanakul Sirin , Amnuywattanakul Tanatta
Published: October 2015

E-learning is a popular technique that can solve learning problems of student. In this study, the learning package of data analysis by using graphing paper to attain linear relationship between independent and dependent variables was invented and utilized. The learning package, consisting of contents and answer key video made from Power Point was converted to video format. The samples were 58 students of Bachelor of Science program who were selected by multi-stage sampling and divided into experimental and control groups. The experimental group composed of 29 students, learnt by using e-learning via LMS Moodle at RMUTP website. The control group, 29 students, was performed by a conventional technique through multimedia teaching with PowerPoint. The research tools consisted of the lesson of graphical analysis, the questionnaire for quality evaluation of the lesson and the achievement evaluation. The results were found that the quality of research tools was very good and the average value of learning achievement of the experimental group was higher than the control group, no significant statistic at level of 0.05 by comparing with statistical method of t-test (n=29). It indicated that e-learning system can be used as a practical tool for increasing skill of the samples as well as correspondence between them in classroom.
Effects of Catalyst on Carbon Nanotubes Synthesized by Thermal Chemical Vapor Deposition Method
Authors: Pakdee Udomdej , Srabua Santipab , Phongphala Aphichard , Pawong Chutchai
Published: October 2015

The effects of cobalt, nickel and iron catalyst on carbon nanotubes (CNTs) were examined with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractrometer (XRD) and Fourier transform Raman spectrometer (FT-Raman). The samples were prepared by the thermal chemical vapor deposition (CVD) method at 780 °C under pressure of acetylene gas (C2H2) at 0.5 bar. The average diameter of CNTs grown on Co, Fe and Ni catalyst obtained from SEM image is 100, 90, 70 nm, respectively. The crystallinity and the yield of CNTs synthesized from Ni catalyst were higher than that from Fe or Co catalyst. The Raman peak of radial breathing mode (RBM) region and the TEM images highlighted the hollow tubes of the CNTs. The results indicated that the diameter, the yield and the crystallinity for synthesis of carbon nanotubes were manipulated by the selection of the catalyst.
Effects of Milling Technique on Physical and Mechanical Properties of Lead-Free Ba(Zr0.3Ti0.7)O3 Ceramics
Authors: Kruae-In Chatchai , Leenakul Wilaiwan
Published: October 2015

Barium zirconium titanate powders with a composition of Ba (Zr0.3Ti0.7)O3 were synthesized by a conventional mixed oxide and vibro-milling method. Ba (Zr0.3Ti0.7)O3 ceramics were fabricated from the synthesized powders. The effects of milling technique on the physical and mechanical properties of the prepared samples were investigated. Compared to conventional samples, the samples prepared by the vibro-milling method showed a higher densification. The vibro-milling methods also produce a higher degree of crystallinity. The microstructure results were correlated with the characteristics of the milling process. The measurement results indicated that the milling technique affected both of physical and mechanical properties of the lead-free BZT ceramics.
Electrical Properties of Y2NiMnO6 Ceramics Sintered at High Temperature
Authors: Sareein Thanapong , Deeyai Panakamon , Putasaeng Bundit , Chathirat Naphat
Published: October 2015

In this work, impedance spectroscopy technique was used in order to investigate the electric properties of double perovskites of the Y2NiMnO6 ceramics, which were prepared by thermal decomposition technique at 800°C for 6 hours and then sintered at a high temperature of 1400°C for 6, 12, 18, and 24 hours. Consequently, the electric characterization of the Y2NiMnO6 ceramics was performed at 30°C °C in the frequency range from 102 Hz to 108 Hz. The results in the Rg with 10,000, 9,990, 6,400, and 1,700 (Ω) at sintering time, respectively. Dispersion was observed in the variation of impedance values with frequency. Possible reason for all the above observation was discussed.
Investigation on Structural and Electrical Property of (1-x) PLZT - x PZN Ceramics
Authors: Chumprasert Ladapak , Funsueb Narit , Somwan Siripong , Limpichaipanit Apichart , Ngamjarurojana Athipong
Published: October 2015

In this study, (1-x)Pb0.92La0.08(Zr0.4Ti0.6)O3 - xPb (Zn1/3Nb2/3)O3 (PLZT-PZN, x = 0, 0.05, 0.10, 0.15 0.20 and 0.25) ceramics with pure perovskite were synthesized by mixed oxide synthetic route via a rapid vibro-milling technique. The ceramic pellets were sintered at 1250°C for 4 h. The phase formation and composition was investigated using X-ray diffraction. The dielectric properties of the densified samples were investigated by LCR meter as a function of temperature and frequency. It can be seen that when optimal amount of PZN was added to tetragonal Pb0.92La0.08(Zr0.4Ti0.6)O3 ceramics, the electrical properties were found to be optimal.
Characterization and Optical Properties of Zinc Oxide Films Prepared by Microwave Technique
Authors: Narksitipan Suparut , Awirut Thaweedet
Published: October 2015

In this research, zinc oxide (ZnO) films were prepared using a wet chemical reaction via a microwave technique. X-ray diffraction techniques (XRD) and energy dispersive x-ray spectroscopy (EDS) were used to study the phases, crystalline structures, chemical compositions and optical properties of the films, respectively. Optical transmittance was also measured through UV-VIS spectroscopy. Surface film morphologies were investigated by scanning electron microscopy (SEM). As a result, a ZnO phase with a hexagonal structure was detected. The EDS spectrum shows that elements of Zn and O were present. The average optical transmittance value for all films was 75% at a wavelength of 370-375 nm, a comparison among the films obtained at different times show a transmittance value slightly higher for films obtained at higher times. A calculation of the energy band gap of ZnO films was estimated to be in the range of 3.31 to 3.35 eV. Additional, the ZnO films showed a smooth surface.
Magnetic Field Dependent Dielectric Properties in Ba(Ti0.99-xMn0.01Tax)O3 Ceramics
Authors: Sareein Thanapong , Ngamjarurojana Athipong , Yimnirun Rattikorn
Published: October 2015

Hybrid-doped BaTiO3 ferroelectric ceramics Ba (Ti(0.99-x)Mn0.01Tax)O3 systems have been prepared by a conventional mixed-oxide method viavibro-milling technique. The dielectric properties at room temperature were observed under magnetic field applied parallel to electric field. The results indicate significant changes of both properties with the magnetic field. Moreover, explained in terms of the induction of magnetization by means of an electric field and induction of polarization according to domain switching of the dielectric properties under the influence of the applied magnetic field.
Properties of Mg Doped ZnO Films Prepared by Ultrasonic Spray Pyrolysis
Authors: Thonglem Sutatip , Sirisoonthorn Somnuk , Pengpat Kamonpan , Rujijanagul Gobwute , Eitssayeam Sukum , Intatha Uraiwan , Tunkasiri Tawee
Published: October 2015

This work is focused on the preparation of Mg doped ZnO films by ultrasonic spray pyrolysis and investigated the physical, optical and electrical properties of the films. These films were prepared from 0.02 M of Zn (CH3OO)2.2H2O and MgCl2 was used for doping. The atomic percentage ratio of Mg/Zn was varied from 0 to 9 at.%. The crystalline phase of all films was identified as ZnO polycrystalline structure with preferred orientation along the (002) plane. While, the grain shape of ZnO film was irregular shape, this shape changed to spherical shape with doped Mg concentration and changed again to rod shape with doped Mg concentration to 9 at.%. Although, the Mg dopant affects the shape of ZnO films but don’t affect resistivity of the films. Moreover, the Mg dopant shifts the absorption edge in transmittance spectra of films to lower wavelength and increases band gap of the films.
Study Behavior of XPS Spectra of Ni, Mn, Y and O in Y2NiMnO6 Ceramics
Authors: Deeyai Panakamon , Sareein Thanapong , Putasaeng Bundit , Chathirat Naphat
Published: October 2015

Bulk Y2NiMnO6 samples were prepared by thermal decomposition technique at 800 °C for 6 hours. The effects of temperature on the structure of ceramics were investigated for different sintering temperatures in the range of 1000-1300 °C, while kept constant the sintering time of 12 hours. Structural characterization had been investigated via X-ray diffraction (XRD) on samples of different sintering temperatures. Results from the experiment had revealed that high temperature affected oxide in ceramic materials. Further analysis with X-ray photoelectron spectroscopy (XPS) technique had revealed an outstanding point of ceramics by investigating the Ni 2p, 2p3/2, Mn 2p1/2, 2p3/2, and Y 3d3/2, 3d5/2 at the surface of Y2NiMnO6 ceramics. The changes in relative intensity of XPS peaks and the shifts in their binding energy (eV) were observed in the results, while the effect of temperature on oxide in ceramics may be investigated with dielectric property in the future.
Effect of Nonlinear Thermal Radiation on MHD Flow between Rotating Plates with Homogeneous-Heterogeneous Reactions
Authors: Janke Venkata Ramana Reddy , Sugunamma Vanagala , Sandeep Naramgari
Published: October 2015

In this study we investigated the effect of nonlinear thermal radiation on magnetohydrodynamic flow between horizontal rotating plates in the presence of homogeneous-heterogeneous reactions. By making use of the appropriate similarity transformations, the equations which govern the flow are reduced to a set of nonlinear ordinary differential equations. Further, these equations are solved numerically using the Runge-Kutta based shooting technique. Also, the effects of various pertinent parameters on velocity, temperature and concentration profiles along with the friction factor, local Nusselt and Sherwood numbers are discussed and presented with the help of graphs and tables. We found an excellent agreement of the present results with the existed literature under some special limited cases. Results indicate that concentration profiles are highly influenced by the homogeneous-heterogeneous parameters. Nonlinear thermal radiation have tendency to enhance the thermal boundary layer thickness.
Heat and Mass Transfer in MHD Mixed Convection Flow on a Moving Inclined Porous Plate
Authors: Veeresh C. , Varma S.V.K. , Kumar B. Rushi , Vijaya Kumar A.G.
Published: October 2015

:The effects of mixed convection with thermal radiation and chemical reaction on MHD flow of viscous, incompressible and electrically conducting fluid on a moving inclined heated porous plate is analyzed. The non-linear coupled partial differential equations are solved by perturbation technique. The influence of different pertinent parameters such as Grashof number (Gr), modified Grashof number (Gm), magnetic field parameter (M), heat source parameter (), chemical reaction parameter (γ), Schmidt number (Sc) and angle of inclination () on velocity, temperature and concentration distribution have been studied and analyzed with the help of graphs. An analysis of the coupled heat and mass transfer phenomena is provided in detail. We observed that velocity decreases for increasing values of the angle of inclination α. The results of the present study are compared with the results obtained by Chaudhary et al. [1], and Dulal et al. [4] in the absence of angle of inclination, our results appear to be in good agreement with the existing results. Key words: Heat and mass transfer, Viscous and Ohmic dissipation, Radiation, Chemical reaction, Inclined, Porous plate.
Numerical Prediction of the Fire Spread in Vegetative Fuels Using NISTWFDS Model
Authors: Miloua Hadj
Published: October 2015

Current study focuses to the application of an advanced physics-based (reaction–diffusion) fire behavior model to the fires spreading through surface vegetation such as grasslands and elevated vegetation such as trees present in forest stands. This model in three dimensions, called Wildland Fire Dynamics Simulator WFDS, is an extension, to vegetative fuels, of the structural FDS developed at NIST. For simplicity, the vegetation was assumed to be uniformly distributed in a tree crown represented by a well defined geometric shape. This work on will focus on predictions of thermal function such as the radiation heat transfer and and thermal function for diverse cases of spatial distribution of vegetation in forest stands. The influence of wind, climate characteristics and terrain topography will also be used to extend and validate the model. The results obtained provide a basis to carry out a risk analysis for fire spread in the studied vegetative fuels in the Mediterranean forest fires.
Using Social Media as a Marketing Tool in Tertiary Institutions: A Case Study of Data Link University, Ghana
Authors: Ghansah Nathaniel Ekow , Ghansah Benjamin , Benuwa Ben Bright , Ocquaye Elias Nii Noye
Published: October 2015

Social media has provided the platform for producers of goods and services to publicize their products and also to be more competitive through the provision of consumer feedback. In recent times, businesses and business owners are becoming more comfortable with including social media as part of their integrated marketing communications and strategies. This paper examines the role of social media as a marketing tool in stimulating demand for commodities, specifically using social media as a marketing tool to influence prospective candidates in their bid to apply to a particular tertiary institution. We examine the current marketing mix being used by Data Link University College, a private tertiary institution located in Ghana and how the inculcation of social media marketing strategies can help improve the system.
Integration of the Extended Gateway Concept in Supply Chain Disruptions Management in East Africa-Conceptual Paper
Authors: Werikhe Gerald Wanzala , Jin Zhi Hong
Published: October 2015

In the recent past, emerging regions of the world have become significant contributorsin powering growth of the global economy. The regions have experienced increase in foreign direct investment, rise in volumes of exports and imports, and an increase in shipping lines towards such regions. Africa in this trend has not been left behind with the IMF reporting that six out of ten fastest growing economies in the world are found in Africa. Specifically, East Africa is one of the regions that have experienced this positive trend relating to moreintegration of the economies, high average GDP growth, and tremendous increase in international freight destined for overseas and inlandthrough the ports of Mombasa and Dares Salaam. The rise in freightvolume however, has resulted into port terminal capacity and productivity challenges, congestion along transport corridors, damage of highways, traffic jam in port cities and environmental pollution hence making the nature of growth and development expensive and unsustainable.
This conceptual paper therefore tries topropose the adoption of the ‘extended gateway concept ‘to be integrated into East Africa’s transportation -logistics systemin order to manage and prevent supply chain related disruptions related to time,costs,reliability and safety .The paper presents a theoretical meaning of the concept, discusses the logistical challenges of East Africa from a shipping perspective, and proposes a ‘Three tier’ Extended gateway model for the region based on the development of inland intermodal terminals or dry ports to achieve a modern, economically and environmentally sustainable fright transportation system.
Modelling and Analysis of Wear Prediction in Machining of Nano Based GFRP Composites Using RSM
Authors: Solairajan A. Saravanapandi , Alexraj S. , Rajan P. Vijaya , Jose Godwin
Published: October 2015

Glass fiber reinforced composite material was fabricated using E-glass fiber with unsaturated polyester resin. In Glass Fiber Reinforced Plastic (GFRP) composites, the matrix of polymer is reinforced with glass fibers. The surface quality and dimensional precision significantly affect the parts during their suitable life, particularly in cases where the components come in contact with other elements or materials. In the current study, GFRP is machined with two cases i.e. with and without Nano combinations in lathe. These machining studies were carried out on lathe using three different cutting tools: namely Carbide (K-20), Cubic Boron Nitrate (CBN) and Polycrystalline Diamond (PCD). The cutting parameters considered were cutting speed, feed, and depth of cut. Surface Finish is the most important parameter measured by main spindle and compares the value with another. A second order mathematical model in terms of cutting parameters was developed using RSM. The results specify the developed model is suitable for prediction of surface roughness in machining of GFRP composites.
Utilization of Crushed Glass Waste in Concrete Samples Prepared with Coal Fly Ash
Authors: Junak Jozef
Published: October 2015

This article is aimed on the study of glass bottle cullet influence on the compressive and flexural strength development of products prepared as the partial natural aggregate replacement by crushed glass waste. For this study, eight different mixtures containing coloured glass cullet as a full replacement of natural aggregate fractions 0/4, 4/8 and 8/16 mm and two comparative mixtures were prepared. In four of these mixtures, 25% of Portland cement were replaced by coal fly ash. After 7, 28 and 90 days of hardening, samples were tested on flexural strength and compression strength. Results showed, that specimens containing full replacement of fraction 8/16 mm of glass cullet reached the highest compressive strength 43.32 MPa corresponding to concrete strength class C 30/37. Partial cement replacement by coal fly ash leads to low compressive strength after 7, 28 and 90 days of curing. Use of coloured glass bottle cullet in concrete should not have negative impact on the strength characteristics of hardened concrete and should have positive effects for preparing quality fair-faced concrete surfaces.
Activated Zeolite and Magnesite as Potential Reactive Materials for Passive Acidic Groundwater Treatment Technology
Authors: Fedoročková Alena , Sučik Gabriel , Raschman Pavel
Published: October 2015

Permeable reactive barriers (PRBs) are passive, in-situ remediation systems that comprise the filtration of a contaminated groundwater through a reactive media able to degrade, adsorb or precipitate the pollutants. Selection of the reactive media depends on the nature of the contamination. While the majority of PRBs are used to treat groundwater contaminated with chlorinated volatile organic compounds or acid mine drainage, the present study is focused on heavy metals, namely Fe, Al, Cu, Ni, Zn, Mn and As. To remove such inorganic pollutants, four methodologies are usually implemented: a) redox reaction, b) adsorption and ion exchange, c) biological treatment (e.g. metal sulphides precipitation) and d) pH control and precipitation.
The present paper deals with the last methodology in which an adjustment of pH by alkalinity-generating materials leads to the precipitation of metal hydroxides and the decrease in the concentration of dissolved species. As the solubility of metals depends on their valence, redox-potential, concentrations and kinetics of reaction, the target pH varies with respect to the considered metal. A pH of about 10 allows the precipitation of hydroxides of divalent ions (zinc, manganese, copper, lead, nickel, cobalt and cadmium), while a pH of around 6-7 is adapted to trivalent ions (iron, aluminium and chromium). However, the accumulation of precipitates in the pore spaces can cause clogging of the pores, hence decrease the porosity and hydraulic conductivity of the reactive media and alter its efficiency. To validate this assumption, the neutralizing ability of alkaline materials such as activated zeolite and magnesite were examined in a test column by monitoring the resultant pH with attention to impact of precipitates on the hydraulic properties of reactive materials. Based on the test results, both materialls are considered suitable to remove the groundwater contaminants with high efficiency (up to 99%) and suitable grain size to encourage flow through the PRB.
Study of Precipitates from Mine Water after Defrosting and Oxidation
Authors: Balintova Magdalena , Demcak Stefan , Holub Marian , Hurakova Maria
Published: October 2015

Acid mine drainage contains many toxic pollutants, mainly heavy metals and sulphates, which have negative impact on the environment. This paper deal with a study of two precipitates from acid mine drainage outflowing from the abandoned mine Smolnik (Slovakia). The precipitates were created after defrosting of mine water and after the process of oxidation. After drying the precipitates were analysed by infrared spectrometry and scanning electron microscopy (SEM) with EDX analysis. Using infrared spectrometry it was found that the precipitate contained OH-, SO42- functional groups. The inhomogeneous structure of the precipitate was observed by SEM with EDX analysis. The presence of CaSO4.2H2O (approx. 90 %) in precipitate after defrosting was confirmed by FTIR and SEM with EDX. Particulate substances after oxidation consisted mainly iron (30.5%), oxygen (44.4 %) and sulphur (7.9 %). Complex compounds with mainly contents of iron (III), hydroxides and sulphate with crystal bound water in structure were identified.
Determination the Availability of Chromium from Powdered Cement Composites Containing Blast Furnace Slag
Authors: Oravec Jozef , Eštoková Adriana
Published: October 2015

Nowadays, cement composites often contain a certain amount of waste materials, which can lead to increased heavy metals leaching. Important environmental indicator of the suitability of concrete is a leachability of chromium. In this paper, concrete samples containing special admixture based on the blast furnace slag as replacement of Portland cement (65%, 75%, 85% and 95%, respectively) as well as reference sample containing only a Portland cement were analyzed. Availability test was used to study the maximum chromium leaching from finely ground cement composites samples. The findings revealed that the leachability of hexavalent chromium from the samples containing 65 and 75 wt. % of slag-based additive was 4.59 and 1.70 times higher, respectively then the leachability of hexavalent chromium from the samples containing no slag. On the other hand, the 85 and 95 wt. % slag-containing-samples provided the Cr (VI) leachability by 26 and 41 % lower than the samples without any slag addition. Regarding the slag containing samples, the higher content of slag-based additive was in concrete sample, the lower leachability of Cr (VI) was detected.
Hybrid Sorption and Microfiltration Characteristics of Zeolite
Authors: Sabo Štefan , Bakalár Tomáš , Búgel Milan , Pavolová Henrieta
Published: October 2015

Industrial wastewater treatment and reuse is one of the principal tasks of present. For this purpose several physical, chemical and combined methods have been used. This paper deals with the study of sorption behaviour of natural zeolite with respect to Zn (II) and Cu (II) followed by cross-flow membrane microfiltration. The experiments realised were aimed at verification of effectiveness of ion exchange of selected metals from wastewater using zeolite – with main component clinoptilolite. The experimental data obtained were fitted using Langmuir and Freundlich isotherms. The sorption capacity was studied for zinc and copper uptake, followed by a study of microfiltration of zeolite suspension using a cross-flow microfiltration device with tubular ceramic membrane. According to experimental results the basic parameters of microfiltration process were evaluated. In comparison with other processes, the hybrid membrane microfiltration offers more effective way of water treatment.
The Synthesis of α-C2S Hydrate Substituted with Al3+ Ions in Mixture with CaO/SiO2 = 1.75
Authors: Baltakys Kestutis , Dambrauskas Tadas , Eisinas Anatolijus
Published: October 2015

The parameters of α-C2SH substituted with Al3+ions hydrothermal synthesis was determined. α-C2SH was synthesized in the primary mixtures with CaO/(SiO2+Al2O3) = 1.75 and Al2O3/(SiO2+Al2O3) = 0; and 0.025. The hydrothermal synthesis has been carried out in unstirred suspensions under saturated steam pressure in argon atmosphere at 175 °C temperature for 4; 8; 16; 24; 48; 72 hours by applying extra argon gas (10 bar). It was determined that in unstirred CaO–SiO2·nH2O–H2O suspensions, the additive of Al2O3changes the formation mechanism of synthesis products as well as their stability during the isothermal curing. It should be noted that in the mixtures with Al2O3, within 4 hours of isothermal curing at 175 °C all Al3+ions were incorporated in the synthesis products structure. However, Al2O3additive has negative influence on the formation of calcium silicate hydrates because even after 24 h of isothermal curing quite intensive diffraction peaks of unreacted portlandite were identified. When hydrothermal synthesis is extended to 48 hours, Ca (OH)2fully reacted and dibasic calcium silicate hydrates start dominate in the products.
Bio-Corrosion Resistance of Concretes Containing Antimicrobial Ground Granulated Blastfurnace Slag BIOLANOVA and Novel Hybrid H-CEMENT
Authors: Strigáč Július , Martauz Pavel , Eštoková Adriana , Števulová Nadežda , Luptáková Alena
Published: October 2015

The article deals with the study of biocorrosion of concretes by sulphuric acid induced by oxidizing bacteria Acidithiobacillus thiooxidans. The concretes were prepared from reference cement CEM I 42,5 N, the mixtures of CEM I 42,5 N and antimicrobial ground granulated blastfurnace slag BIOLANOVA (GGBS) (with amount of GGBS 65 mass % - CEM III/A 32,5 N, 75 mass % - CEM III/B 32,5 N, 85 mass % - CEM III/C 32,5 N a 95 mass % - CEM III/C 32,5 N) and novel hybrid cement H-CEMENT (HC). The experiments were carried out in model laboratory conditions at 30 °C during 91 days. The degree of deterioration of concrete samples has been studied on the base of the pH changes of leachate, the concentrations of selected ions such as S, Ca and Si and the mass changes. It has been clearly confirmed, that in the presence of bacteria, the pronounced degradation of the samples occurred with exception of HC sample, which behaviour proved differences to the other samples. The HC concrete possessed more alkali leachate in comparison with the others. The concentration of sulphur S in leachate was increased by metabolic activity of bacteria due to biogenic H2SO4 formation. The increase of S concentration acidified leachate and so promoted leaching next substances from the samples. The concentration of silicon Si in leachate was promoted by metabolic activity of bacteria, as well. The development of Ca leaching concentration has been similar at all composite samples as in the case of reference CEM I 42,5 N concrete, however the smallest portion of leached Ca has been determined at HC concrete. The Ca leaching concentration has been increasing with the amount of GGBS being added to the composite CEM III concretes. The different tendency has been also observed at the HC samples in regards to the mass changes. The increase in mass has been measured at all concrete samples with exception of HC concrete, at which the mass decrease has been found out. The results confirmed the resistance of the concrete composite samples containing GGBS and HC to the sulphate attack and the HC sample showed the highest resistance to the sulphate biocorrosion.
Thymic Epithelial Cells Are a Nonredundant Source of Wnt Ligands for Thymus Development
Authors: Brunk Fabian , Augustin Iris , Meister Michael , Boutros Michael , Kyewski Bruno
Published: October 2015

Wnt signaling has been implicated in T cell development. However, it remained unclear which cell type is the major source of Wnt ligands and to what extent thymic epithelial cell (TEC) development is dependent on Wnt signaling. In this study, we analyzed the role of Wnt ligands provided by TECs for the development of T cells and TECs without manipulating the intracellular Wnt signaling machinery in either cell type. To this end, we used conditional knockout mice (FoxN1-Gpr177) in which TECs are unable to secrete Wnt ligands. Gpr177 (Evi/Wls) is a Wnt-specific cargo receptor that is required for the secretion of Wnt ligands. We found that TECs are the main source of Wnt ligands in the thymus, which serves a nonredundant role, and lack of TEC-provided Wnt ligands led to thymic hypotrophy, as well as a reduced peripheral T cell pool. Despite being reduced in numbers, T cells that developed in the absence of TEC-secreted Wnt ligands were functionally competent, and the subset composition of the peripheral T cell pool was not affected. Thus, our data suggest that T cell development is not directly dependent on TEC-provided Wnt ligands. Rather, TEC-secreted Wnt ligands are essential for normal thymus development and normal peripheral T cell frequencies but are dispensable for T cell function in the periphery.
Immunohistochemical Markers of Soft Tissue Tumors: Pathologic Diagnosis, Genetic Contributions, and Therapeutic Options
Authors: Parham David M.
Published: October 2015

After ~30 years of widespread usage, immunohistochemistry (IHC) has become a standard method of diagnosis for surgical pathology. Because of the plethora of diagnoses and often subtle nature of diagnostic criteria, IHC finds particular utility in soft tissue tumors. The use of progressively small amounts of tissue for diagnosis highlights the importance of this method. The sensitivity and crispness of IHC stains have progressively improved with the advent of new techniques. Traditionally, IHC detects cell-typic markers that characterize cell phenotypes, such as chromogranin for neuroectodermal tissue, myogenin for skeletal muscle, and cytokeratin for epithelium. However, the advent of genetic discoveries have led to IHC testing for detection of fusion gene products or overexpressed oncogenes associated with deletions and mutations. Proliferation-based markers such as Ki-67 can also be used for prognosis and grading, but more standardization is needed. Development of monoclonal antibody-based pharmaceuticals, such as imatinib or crizotinib, holds the promise of tailored anticancer therapy. IHC thus has assumed importance not only for diagnosis but also for guidance of personalized medicine.
Application of the Steady-state Variable Nutation Angle Method for Faster Determinations of Long T1S–-an Approach Useful for the Design of Hyperpolarized Mr Molecular Probes
Authors: Jupin Marc , Gamliel Ayelet , Hovav Yonatan , Sosna Jacob , Gomori J. Moshe , Katz-Brull Rachel
Published: October 2015

In the dissolution-dynamic nuclear polarization technique, molecular probes with long T1s are preferred. 13C nuclei of small molecules with no directly bonded protons or sp313C nuclei with proton positions substituted by deuterons may fulfill this requirement. The T1 determination of such new molecular probes is crucial for the success of the hyperpolarized observation. Although the inversion-recovery approach remained by and large the standard for T1 measurements, we show here that the steady-state variable nutation angle approach is faster and may be better suited for the determination of relatively long T1s in thermal equilibrium. Specifically, the T1 of a new molecular probe, [uniformly labeled (UL)-13C6, UL-2H8]2-deoxy-d-glucose, is determined here and compared to that of [UL-13C6, UL-2H7]d-glucose.
A numerical invariant for linear representations of finite groups
Authors: Karpenko Nikita A. , Reichstein Zinovy
Published: October 2015

We study the notion of essential dimension for a linear representation of a finite group. In characteristic zero we relate it to the canonical dimension of certain products of Weil transfers of generalized Severi–Brauer varieties. We then proceed to compute the canonical dimension of a broad class of varieties of this type, extending earlier results of the first author. As a consequence, we prove analogues of classical theorems of R. Brauer and O. Schilling about the Schur index, where the Schur index of a representation is replaced by its essential dimension. In the last section we show that in the modular setting ed(

\rho

) can be arbitrary large (under a mild assumption on

G

). Here

G

is fixed, and

\rho

is allowed to range over the finite-dimensional representations of

G

. The appendix gives a constructive version of this result.
Exceptional hyperbolic 3-manifolds
Authors: Gabai David , Trnkova Maria
Published: October 2015

We correct and complete a conjecture of D. Gabai, R. Meyerhoff and N. Thurston on the classification and properties of thin tubed closed hyperbolic 3-manifolds. We additionally show that if

N

is a closed hyperbolic 3-manifold, then either

N=Vol3

or

N

contains a closed geodesic that is the core of an embedded tube of radius

\mathrm {log}(3)/2

.
Rezensionen
Authors: Haldimann Andreas
Published: October 2015

Rezension zu:
N. Weaver:
Forcing for Mathematicians
. 150 Seiten, e 55.–. World Scientific Publishing, Singapore, 2014; ISBN 978-981-456600-1.
The BNS-invariant for the pure braid groups
Authors: Koban Nic , McCammond Jon , Meier John
Published: October 2015

In 1987 Bieri, Neumann and Strebel introduced a geometric invariant for discrete groups. In this article we compute and explicitly describe the BNS-invariant for the pure braid groups.
Sharp lower bounds for the asymptotic entropy of symmetric random walks
Authors: Gouëzel Sébastien , Mathéus Frédéric , Maucourant François
Published: October 2015

The entropy, the spectral radius and the drift are important numerical quantities associated to random walks on countable groups. We prove sharp inequalities relating those quantities for walks with a finite second moment, improving upon previous results of Avez, Varopoulos, Carne, Ledrappier. We also deduce inequalities between these quantities and the volume growth of the group. Finally, we show that the equality case in our inequality is rather rigid.
A new function space and applications
Authors: Bourgain Jean , Brezis Haïm , Mironescu Petru
Published: October 2015

We define a new function space

B

, which contains in particular BMO, BV, and

W^{1/p,p}

,

1 < p < \infty

. We investigate its embedding into Lebesgue and Marcinkiewicz spaces. We present several inequalities involving

L^p

norms of integer-valued functions in

B

. We introduce a significant closed subspace,

B_0

, of

B

, containing in particular VMO and

W^{1/p,p}

,

1 \le p < \infty

. The above mentioned estimates imply in particular that integer-valued functions belonging to

B_0

are necessarily constant. This framework provides a "common roof" to various, seemingly unrelated, statements asserting that integer-valued functions satisfying some kind of regularity condition must be constant.
Bistable traveling waves for monotone semiflows with applications
Authors: Fang Jian , Zhao Xiao-Qiang
Published: October 2015

This paper is devoted to the study of traveling waves for monotone evolution systems of bistable type. In an abstract setting, we establish the existence of traveling waves for discrete and continuous-time monotone semiflows in homogeneous and periodic habitats. The results are then extended to monotone semiflows with weak compactness. We also apply the theory to four classes of evolution systems.
Extremal metrics and lower bound of the modified K-energy
Authors: Sano Yuji , Tipler Carl
Published: October 2015

We provide a new proof of a result of X.X. Chen and G.Tian [5]: for a polarized extremal Kähler manifold, the minimum of the modified K-energy is attained at an extremal metric. The proof uses an idea of C. Li [16] adapted to the extremal metrics using some weighted balanced metrics.
The Brauer category and invariant theory
Authors: Lehrer Gustav I. , Zhang Ruibin
Published: October 2015

A category of Brauer diagrams, analogous to Turaev's tangle category, is introduced, a presentation of the category is given, and full tensor functors are constructed from this category to the category of tensor representations of the orthogonal group O

(V)

or the symplectic group Sp

(V)

over any field of characteristic zero. The first and second fundamental theorems of invariant theory for these classical groups are generalised to the category theoretic setting. The major outcome is that we obtain presentations for the endomorphism algebras of the module

V^{\otimes r}

, which are new in the classical symplectic case and in the orthogonal and symplectic quantum case, while in the orthogonal classical case, the proof we give here is more natural than in our earlier work. These presentations are obtained by appending to the standard presentation of the Brauer algebra of degree

r

one additional relation. This relation stipulates the vanishing of a single element of the Brauer algebra which is quasi-idempotent, and which we describe explicitly both in terms of diagrams and algebraically. In the symplectic case, if dim

V=2n

, the element is precisely the central idempotent in the Brauer subalgebra of degree

n+1

, which corresponds to its trivial representation. Since this is the Brauer algebra of highest degree which is semisimple, our generator is an exact analogue for the Brauer algebra of the Jones idempotent of the Temperley-Lieb algebra. In the orthogonal case the additional relation is also a quasi-idempotent in the integral Brauer algebra. Both integral and quantum analogues of these results are given, the latter of which involve the BMW algebras.
Torsion points on families of simple abelian surfaces and Pell's equation over polynomial rings (with an appendix by E. V. Flynn)
Authors: Masser David , Zannier Umberto
Published: October 2015

In recent papers we proved a special case of a variant of Pink's Conjecture for a variety inside a semiabelian scheme: namely for any curve inside anything isogenous to a product of two elliptic schemes. Here we go beyond the elliptic situation by settling the crucial case of any simple abelian surface scheme defined over the field of algebraic numbers, thus confirming an earlier conjecture of Shou-Wu Zhang. This is of particular relevance in the topic, also in view of very recent counterexamples by Bertrand. Furthermore there are applications to the study of Pell equations over polynomial rings; for example we deduce that there are at most finitely many complex

t

for which there exist

A,B \neq 0

in

{\mathbb C}[X]

with

A^2 – DB^2 = 1

for

D = X^6 + X + t

. We also consider equations

A^2 – DB^2 = c'X + c

, where the situation is quite different.
Generating series and asymptotics of classical spin networks
Authors: Costantino Francesco , Marché Julien
Published: October 2015

We study classical spin networks with group SU

_2

. In the first part, using Gaussian integrals, we compute their generating series in the case where the edges are equipped with holonomies; this generalizes Westbury’s formula. In the second part, we use an integral formula for the square of the spin network and perform stationary phase approximation under some non-degeneracy hypothesis. This gives a precise asymptotic behavior when the labels are rescaled by a constant going to infinity.
Brauer relations in finite groups
Authors: Bartel Alex , Dokchitser Tim
Published: October 2015

If

G

is a non-cyclic finite group, non-isomorphic

G

-sets

X, Y

may give rise to isomorphic permutation representations

\mathbb C[X ]\cong \mathbb C[Y]

. Equivalently, the map from the Burnside ring to the rational representation ring of

G

has a kernel. Its elements are called Brauer relations, and the purpose of this paper is to classify them in all finite groups, extending the Tornehave–Bouc classification in the case of

p

-groups.
On Kakeya–Nikodym averages, $L^p$-norms and lower bounds for nodal sets of eigenfunctions in higher dimensions
Authors: Blair Matthew D. , Sogge Christopher D.
Published: October 2015

We extend a result of the second author [27, Theorem 1.1] to dimensions

d \geq 3

which relates the size of

L^p

-norms of eigenfunctions for

2 < p < 2(d+1) / d-1

to the amount of

L^2

-mass in shrinking tubes about unit-length geodesics. The proof uses bilinear oscillatory integral estimates of Lee [22] and a variable coefficient variant of an "

\epsilon

removal lemma" of Tao and Vargas [35]. We also use Hörmander's [20]

L^2

oscillatory integral theorem and the Cartan–Hadamard theorem to show that, under the assumption of nonpositive curvature, the

L^2

-norm of eigenfunctions

e_{\lambda}

over unit-length tubes of width

\lambda^{-1/2}

goes to zero. Using our main estimate, we deduce that, in this case, the

L^p

-norms of eigenfunctions for the above range of exponents is relatively small. As a result, we can slightly improve the known lower bounds for nodal sets in dimensions

d \ge 3

of Colding and Minicozzi [10] in the special case of (variable) nonpositive curvature.
Soft local times and decoupling of random interlacements
Authors: Popov Serguei , Teixeira Augusto
Published: October 2015

In this paper we establish a decoupling feature of the random interlacement process

\mathcal{I}^u \subset \mathbb Z^d

at level

u

,

d \geq 3

. Roughly speaking, we show that observations of

\mathcal{I}^u

restricted to two disjoint subsets

A_1

and

A_2

of

\mathbb Z^d

are approximately independent, once we add a sprinkling to the process

\mathcal{I}^u

by slightly increasing the parameter

u

. Our results differ from previous ones in that we allow the mutual distance between the sets

A_1

and

A_2

to be much smaller than their diameters. We then provide an important application of this decoupling for which such flexibility is crucial. More precisely, we prove that, above a certain critical threshold

u_{**}

, the probability of having long paths that avoid

\mathcal{I}^u

is exponentially small, with logarithmic corrections for

d=3

.

To obtain the above decoupling, we first develop a general method for comparing the trace left by two Markov chains on the same state space. This method is based in what we call the soft local time of a chain. In another crucial step towards our main result, we also prove that any discrete set can be “smoothened” into a slightly enlarged discrete set, for which its equilibrium measure behaves in a regular way. Both these auxiliary results are interesting in themselves and are presented independently from the rest of the paper.
The Roquette category of finite $p$-groups
Authors: Bouc Serge
Published: October 2015

Let

p

be a prime number. This paper introduces the
Roquette category

\mathcal{R}_p

of finite

p

-groups, which is an additive tensor category containing all finite

p

-groups among its objects. In

\mathcal{R}_p

, every finite

p

-group

P

admits a canonical direct summand

\partial P

, called
the edge
of

P

. Moreover

P

splits uniquely as a direct sum of edges of

Roquette

p

-groups

, and the tensor structure of

\mathcal{R}_p

can be described in terms of such edges.

The main motivation for considering this category is that the additive functors from

\mathcal{R}_p

to abelian groups are exactly the

rational

p

-biset functors

. This yields in particular very efficient ways of computing such functors on arbitrary

p

-groups: this applies to the representation functors

R_K

, where

K

is any field of characteristic 0, but also to the functor of units of Burnside rings, or to the torsion part of the Dade group.
Cubic moments of Fourier coefficients and pairs of diagonal quartic forms
Authors: Brüdern Jörg , Wooley Trevor D.
Published: October 2015

We establish the non-singular Hasse principle for pairs of diagonal quartic equations in 22 or more variables. Our methods involve the estimation of a certain entangled two-dimensional 21st moment of quartic smooth Weyl sums via a novel cubic moment of Fourier coefficients.
Regularity of stable solutions of $p$-Laplace equations through geometric Sobolev type inequalities
Authors: Castorina Daniele , Sanchón Manel
Published: October 2015

We prove a Sobolev and a Morrey type inequality involving the mean curvature and the tangential gradient with respect to the level sets of the function that appears in the inequalities. Then, as an application, we establish
a priori
estimates for semistable solutions of

–\Delta_p u= g(u)

in a smooth bounded domain

\Omega\subset \mathbb{R}^n

. In particular, we obtain new

L^r

and

W^{1,r}

bounds for the extremal solution

u^\star

when the domain is strictly convex. More precisely, we prove that

u^\star\in L^{\infty}(\Omega)

if

n\leq p+2

and

u^\star \in L^{\frac{np}{n-p-2}} (\Omega) \cap W^{1,p}_0 (\Omega)

if

n > p + 2

.
$\mathbf A^1$-homotopy theory of noncommutative motives
Authors: Tabuada Gonçalo
Published: October 2015

In this article we continue the development of a theory of noncommutative motives, initiated in [30]. We construct categories of

{\bf A}^1

-homotopy noncommutative motives, describe their universal properties, and compute their spectra of morphisms in terms of Karoubi–Villamayor's

K

-theory (

KV

) and Weibel's homotopy

K

-theory (

KH

). As an application, we obtain a complete classification of all the natural transformations defined on

KV, KH

. This leads to a streamlined construction of Weibel's homotopy Chern character from

KV

to periodic cyclic homology. Along the way we extend Dwyer–Friedlander's étale

K

-theory to the noncommutative world, and develop the universal procedure of forcing a functor to preserve filtered homotopy colimits.
Multiplicative structures on the twisted equivariant K-theory of finite groups
Authors: Galindo César , Gutiérrez Ismael , Uribe Bernardo
Published: October 2015

Let

K

be a finite group and let

G

be a finite group acting on

K

by automorphisms. In this paper we study two different but intimately related subjects: on the one side we classify all possible multiplicative and associative structures with which one can endow the twisted

G

-equivariant K-theory of

K

, and on the other, we classify all possible monoidal structures with which one can endow the category of twisted and

G

-equivariant bundles over

K

. We achieve this classification by encoding the relevant information in the cochains of a sub double complex of the double bar resolution associated to the semi-direct product

K \rtimes G

; we use known calculations of the cohomology of

K

,

G

and

K \rtimes G

to produce concrete examples of our classification.

In the case in which

K=G

and

G

acts by conjugation, the multiplication map

G \rtimes G \to G

is a homomorphism of groups and we define a shuffle homomorphism which realizes this map at the homological level. We show that the categorical information that defines the Twisted Drinfeld Double can be realized as the dual of the shuffle homomorphism applied to any 3-cocycle of

G

. We use the pullback of the multiplication map in cohomology to classify the possible ring structures that the Grothendieck ring of representations of the Twisted Drinfeld Double may have, and we include concrete examples of this procedure.
The Higson–Mackey analogy for finite extensions of complex semisimple groups
Authors: Skukalek John R.
Published: October 2015

In the 1970s, George Mackey pointed out an analogy that exists between tempered representations of semisimple Lie groups and unitary representations of associated semidirect product Lie groups. More recently, Nigel Higson refined Mackey’s analogy into a one-to-one correspondence for connected complex semisimple groups, and in doing so obtained a novel verification of the Baum–Connes conjecture with trivial coefficients for such groups. Here we extend Higson’s results to any Lie group with finitely many connected components whose connected component of the identity is complex semisimple. Our methods include Mackey’s description of unitary representations of group extensions involving projective unitary representations, as well as the notion of twisted crossed product

C^*

-algebra introduced independently by Green and Dang Ngoc.