On Four-Dimensional Paracomplex Structures with Norden Metrics

We study almost paracomplex structures with Norden metric on Walker 4-manifolds and try to find general solutions for the integrability of these structures on suitable local coordinates. We also discuss para-Kähler (paraholomorphic) conditions for these structures.Вивчаються майже паракомплексні структури з метрикою Нордена на 4-многовидах Уолкера. Встановлено загальні розв'язки щодо інтегровності таких структур у відповідних локальних координатах. Також обговорюються пара-кєлєрові (параголоморфні) умови для таких структур

Short and user-friendly: The development and validation of the Mini-DBQ

The Driver Behavior Questionnaire (DBQ) is used to measure aberrant driver behavior by asking drivers how often they engage in various aberrant driver behaviors. Since the development of the original DBQ several modified versions have been developed. The difference between the various versions is that new items are added or existing items modified or excluded. However, despite the differences, all versions are relatively long and therefore time-consuming and tiring to answer, which might limit the usability of the instrument. The main purpose of the present study was to develop a mini DBQ version by reducing the 27-item original DBQ to the shortest possible DBQ version. A second aim was to explore the feasibility of a second-order structure within the data, which means that violations, errors and lapses factors load on a higher-order aberrant driver behavior factor. The presence of a second-order structure further indicates the validity of the DBQ and its theoretical structure. Confirmatory factor analysis (CFA) was used to test the fit (i.e., how well the models explain the data) of the original DBQ versus the fit of the shortest possible DBQ as well as the presence of a second-order structure for the DBQ. The results indicated a nine-item Mini-DBQ In addition, a second-order structure was established in the data. These findings indicate that the Mini-DBQ is a valid and useful short measure of aberrant driver behavior

ANSYS Creep-Fatigue Assessment tool for EUROFER97 components

The damage caused by creep-fatigue is an important factor for materials at high temperatures. For in- vessel components of fusion reactors the material EUROFER97 is a candidate for structural application where it is subjected to irradiation and cyclic thermo-mechanical loads. To be able to evaluate fusion reactor components reliably, creep-fatigue damage has to be taken into account. In the frame of Engi- neering Data and Design Integration (EDDI) in EUROfusion Technology Work Programme rapid and easy design evaluation is very important to predict the critical regions under typical fusion reactor loading conditions. The presented Creep-Fatigue Assessment (CFA) tool is based on the creep-fatigue rules in ASME Boiler Pressure Vessel Code (BPVC) Section 3 Division 1 Subsection NH which was adapted to the material EUROFER97 and developed for ANSYS. The CFA tool uses the local stress, maximum elastic strain range and temperature from the elastic analysis of the component performed with ANSYS. For the as- sessment design fatigue and stress to rupture curves of EUROFER97 as well as isochronous stress vs. strain curves determined by a constitutive model considering irradiation influence are used to deal with creep-fatigue damage. As a result allowable number of cycles based on creep-fatigue damage interaction under given hold times and irradiation rates is obtained. This tool can be coupled with ANSYS MAPDL and ANSYS Workbench utilizing MAPDL script files

Gould Belt Members in X-ray RAVE: Cross-Matching RAVE Stars with 3XMM Point Sources

In this paper the results of matching the RAdial Velocity Experiment (RAVE), a spectroscopic Southern hemisphere survey (9 $< I_{DENIS} <$ 12), and XMM-Newton Serendipitous Source Catalogue (3XMM) are presented. The latest data releases of RAVE and XMM were matched and a X-ray RAVE catalogue of 1071 stars was obtained. Then the catalogue was checked for possible Gould Belt (GB) members. We obtained a subsample of 10 stars that meet the GB membership criteria. This subsample and GB member candidates were tested photometrically and kinematically. Among the members there are two BY Dra type variables, an NGC2451 open cluster member, a high proper motion star. The rest are regular main sequence stars. The members have very low velocity dispersions which lead us to think that the members belong in a single structure. We also found out that a kinematical GB membership test might be possible to derive given a large enough GB member sample as they fit in a narrow interval in space velocity diagrams.Comment: Accepted by Astrophysics and Space Scienc

A new type of Na+-driven ATP synthase membrane rotor with a two-carboxylate ion-coupling motif

Abstract: The anaerobic bacterium Fusobacterium nucleatum uses glutamate decarboxylation to generate a transmembrane gradient of Na+. Here, we demonstrate that this ion-motive force is directly coupled to ATP synthesis, via an F1Fo-ATP synthase with a novel Na+ recognition motif, shared by other human pathogens. Molecular modeling and free-energy simulations of the rotary element of the enzyme, the c-ring, indicate Na+ specificity in physiological settings. Consistently, activity measurements showed Na+ stimulation of the enzyme, either membrane-embedded or isolated, and ATP synthesis was sensitive to the Na+ ionophore monensin. Furthermore, Na+ has a protective effect against inhibitors targeting the ion-binding sites, both in the complete ATP synthase and the isolated c-ring. Definitive evidence of Na+ coupling is provided by two identical crystal structures of the c11 ring, solved by X-ray crystallography at 2.2 and 2.6 Å resolution, at pH 5.3 and 8.7, respectively. Na+ ions occupy all binding sites, each coordinated by four amino acids and a water molecule. Intriguingly, two carboxylates instead of one mediate ion binding. Simulations and experiments demonstrate that this motif implies that a proton is concurrently bound to all sites, although Na+ alone drives the rotary mechanism. The structure thus reveals a new mode of ion coupling in ATP synthases and provides a basis for drug-design efforts against this opportunistic pathogen. Author Summary: Essential cellular processes such as biosynthesis, transport, and motility are sustained by the energy released in the hydrolysis of ATP, the universal energy carrier in living cells. Most ATP in the cell is produced by a membrane-bound enzyme, the ATP synthase, through a rotary mechanism that is coupled to the translocation of ions across the membrane. The majority of ATP synthases are energized by transmembrane electrochemical gradients of protons (proton-motive force), but a number of organisms, including some important human pathogens, use gradients of sodium ions instead (sodium-motive force). The ion specificity of ATP synthases is determined by a membrane-embedded sub-complex, the c-ring, which is the smallest known biological rotor. The functional mechanism of the rotor ring and its variations among different organisms are of wide interest, because of this enzyme's impact on metabolism and disease, and because of its potential for nanotechnology applications. Here, we characterize a previously unrecognized type of Na+-driven ATP synthase from the opportunistic human pathogen Fusobacterium nucleatum, which is implicated in periodontal diseases. We analyzed this ATP synthase and its rotor ring through a multi-disciplinary approach, combining cell-growth and biochemical assays, X-ray crystallography and computer-simulation methods. Two crystal structures of the membrane rotor were solved, at low and high pH, revealing an atypical ion-recognition motif mediated by two carboxylate side-chains. This motif is shared by other human pathogens, such as Mycobacterium tuberculosis or Streptococcus pneumonia, whose ATP synthases are targets of novel antibiotic drugs. The implications of this ion-recognition mode on the mechanism of the ATP synthase and the cellular bioenergetics of F. nucleatum were thus examined. Our results provide the basis for future pharmacological efforts against this important pathogen

The 2008 August 1 Eclipse Solar-Minimum Corona Unraveled

We discuss results stemming from observations of the white-light and [Fe XIV] emission corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light corona, visible up to 20 solar radii, was of a transient type with well-pronounced helmet streamers situated above a chain of prominences at position angles 48, 130, 241 and 322 degrees. A variety of coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an original method of image processing, stars up to 12 magnitude, a Kreutz-group comet (C/2008 O1), and a coronal mass ejection (CME) were also detected, with the smallest resolvable structures being of, and at some places even less than, 1 arcsec. Differences, presumably motions, in the corona and prominences are seen even with the 19-min time difference between our sites. In addition to the high-resolution coronal images, which show the continuum corona (K-corona) that results from electron scattering of photospheric light, images of the overlapping green-emission-line (530.3 nm, [Fe XIV]) corona were obtained with the help of two narrow-passband filters (centered on the line itself and for the continuum in the vicinity of 529.1 nm, respectively), each with FWHM of 0.15 nm. Through solar observations, on whose scheduling and details we consulted, with the Solar and Heliospheric Observatory, Hinode's XRT and SOT, TRACE, and STEREO, as well as Wilcox Solar Observatory and SOHO/MDI magnetograms, we set our eclipse observations in the context of the current unusually low and prolonged solar minimum.Comment: Accepted in The Astrophysical Journal, 6 July 200

WC/Co-Ti Kompozitlerinin ısıl ve elastik özelliklerinin ultrasonik dalga hızı ile ilişkisi

In this study,it is aimed to produce various composites and reveal their physical properties. Tungsten carbide (WC) powder and the two of cobalt (Co) and titanium (Ti) powders as binder phase have been used for the preparation of WC-Co-Ti ceramic-metal composite with powder metallurgy. Two different ultrasonic non-destructive techniques were employed to measure the mechanical wave velocity in WCCo-Ti composites. The study was performed on various specimens with different WCx content at the range from 60 to 80% and Co/Ti content in 3:1, 1:1 and 1:3 groups. The WCx content in examined materials was determined using the standard destructive analysis. The Young modulus (E) of the produced composites and the ultrasonic velocity measured through ultrasonic pulse-echo method and immersion method. Thermal conductivity of samples has been measured via hot disk method. The relation between the Young modulus' values with ultrasonic wave velocity, which is obtained through two different methods and thermal conductivity has been physically examined and the results have been compared with the literature

Effect of concentrated growth factor on survival of diced cartilage graft

Background Diced cartilage grafts are important in rhinoplasty for raising the dorsum and eliminating dorsal irregularities. The most common problems with the use of diced cartilage are wrapping and cartilage resorption. Objectives To histopathologically investigate and compare the viability of diced cartilage grafts wrapped with concentrated growth factor, fascia and fenestrated fascia, or blood glue. Methods Cartilage grafts were harvested from the ears of 10 New Zealand White rabbits and diced into 0.5 to 1 mm3 pieces. The grafts were divided into five groups for comparison: (1) bare diced cartilage; (2) diced cartilage wrapped with fascia; (3) diced cartilage wrapped with fenestrated fascia; (4) diced cartilage wrapped with concentrated growth factor (CGF); and (5) diced cartilage wrapped with blood glue. Each of the five grafts was autologously implanted into a subcutaneous pocket in the back of each rabbit. Three months later, the rabbits were sacrificed and the implants were harvested and examined histopathologically. Results Nucleus loss, calcification, inflammation, and giant cell formation differed significantly between the CGF group and both fascia groups. Chondrocyte proliferation was the highest in the CGF group. Nucleus loss rates were similar between the fascia and fenestrated fascia groups. Conclusions Our findings suggest that CGF improves the viability of diced cartilage grafts, while fascia hampers it. Punching holes in the fascia does not improve diced cartilage graft viability and neither does blood glue wrapping. © copyright Crown 2016