Radial Slope Research Articles

BeM(CO)3- (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt): Triply bonded terminal beryllium in zero oxidation state.

We perform detailed potential energy surface explorations of BeM(CO)3- (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt) using both single-reference and multireference-based methods. The present results at the CASPT2(12,12)/def2-QZVPD//M06-D3/def2-TZVPPD level reveal that the global minimum of BeM(CO)3- (M = Co, Rh, Ir) and BePt(CO)3 is a C3v symmetric structure with an 1A1 electronic state, where Be is located in a terminal position bonded to M along the center axis. For other cases, the C3v symmetric structure is a low-lying local minimum. Although the present complexes are isoelectronic with the recently reported BFe(CO)3- complex having a B-Fe quadruple bond, radial orbital-energy slope (ROS) analysis reveals that the highest occupied molecular orbital (HOMO) in the title complexes is slightly antibonding in nature, which bars a quadruple bonding assignment. Similar weak antibonding nature of HOMO in the previously reported BeM(CO)4 (M = Ru, Os) complexes is also noted in ROS analysis. The bonding analysis through energy decomposition analysis in combination with the natural orbital for chemical valence shows that the bonding between Be and M(CO)3q (q = -1 for M = Co, Rh, Ir and q = 0 for M = Ni, Pd, Pt) can be best described as Be in the ground state (1S) interacting with M(CO)30/- via dative bonds. The Be(spσ) → M(CO)3q σ-donation and the complementary Be(spσ) ← M(CO)3q σ-back donation make the overall σ bond, which is accompanied by two weak Be(pπ) ← M(CO)3q π-bonds. These complexes represent triply bonded terminal beryllium in an unusual zero oxidation state.

Origin of neutron-capture elements with the Gaia-ESO survey: the evolution of s- and r-process elements across the Milky Way

ABSTRACT We investigate the origin of neutron-capture elements by analysing their abundance patterns and radial gradients in the Galactic thin disc. We adopt a detailed two-infall chemical evolution model for the Milky Way, including state-of-the-art nucleosynthesis prescriptions for neutron-capture elements. We consider r-process nucleosynthesis from merging neutron stars (MNS) and magneto-rotational supernovae (MR-SNe), and s-process synthesis from low- and intermediate-mass stars (LIMS) and rotating massive stars. The predictions of our model are compared with data from the sixth data release of the Gaia-ESO survey, from which we consider 62 open clusters with age ≳ 0.1 Gyr and ∼1300 Milky Way disc field stars. We conclude that: (i) the [Eu/Fe] versus [Fe/H] diagram is reproduced by both prompt and delayed sources, with the prompt source dominating Eu production; (ii) rotation in massive stars significantly contributes to the first peak s-process elements, but MNS and MR-SNe are necessary to match the observations; and (iii) our model slightly underpredicts Mo and Nd, while accurately reproducing the [Pr/Fe] versus [Fe/H] trend. Regarding the radial gradients, we find that: (i) our predicted [Fe/H] gradient slope agrees with observations from Gaia-ESO and other high-resolution spectroscopic surveys; (ii) the predicted [Eu/H] radial gradient slope is steeper than the observed one, regardless of how quick the production of Eu is, prompting discussion on different Galaxy-formation scenarios and stellar radial migration effects; and (iii) elements in the second s-process peak as well as Nd and Pr exhibit a plateau at low-Galactocentric distances, likely due to enhanced enrichment from LIMS in the inner regions.

Semiempirical Models of Speedup Effect for Downburst Wind Field over 3-D Hills

Downbursts occur frequently in mountainous regions, such as the southwest of China, and causing extensive damage to engineering structures. While some researchers have developed semiempirical models for the speedup effect, most are based on the wind field in the boundary layer over the hill, and there is a lack of semiempirical models for the downburst wind field over the hill. This study employs three RANS (Reynolds Average Navier-Stokes) turbulence models to numerically simulate the downburst wind field over a quadratic curved hill. The realizable k-ε model is selected as the optimal model for the subsequent numerical simulations based on comparison with wind tunnel test results. Then, a semiempirical model of the speedup effect of the downburst wind field over the hill is constructed by numerically simulating the downburst wind field over the hill with different radial locations and different slopes. Finally, the constructed semiempirical model is validated and demonstrates good accuracy.

TDCOSMO

When strong gravitational lenses are to be used as an astrophysical or cosmological probe, models of their mass distributions are often needed. We present a new, time-efficient automation code for the uniform modeling of strongly lensed quasars withGLEE, a lens-modeling software for multiband data. By using the observed positions of the lensed quasars and the spatially extended surface brightness distribution of the host galaxy of the lensed quasar, we obtain a model of the mass distribution of the lens galaxy. We applied this uniform modeling pipeline to a sample of nine strongly lensed quasars for which images were obtained with the Wide Field Camera 3 of theHubbleSpace Telescope. The models show well-reconstructed light components and a good alignment between mass and light centroids in most cases. We find that the automated modeling code significantly reduces the input time during the modeling process for the user. The time for preparing the required input files is reduced by a factor of 3 from ~3 h to about one hour. The active input time during the modeling process for the user is reduced by a factor of 10 from ~ 10 h to about one hour per lens system. This automated uniform modeling pipeline can efficiently produce uniform models of extensive lens-system samples that can be used for further cosmological analysis. A blind test that compared our results with those of an independent automated modeling pipeline based on the modeling softwareLenstronomyrevealed important lessons. Quantities such as Einstein radius, astrometry, mass flattening, and position angle are generally robustly determined. Other quantities, such as the radial slope of the mass density profile and predicted time delays, depend crucially on the quality of the data and on the accuracy with which the point spread function is reconstructed. Better data and/or a more detailed analysis are necessary to elevate our automated models to cosmography grade. Nevertheless, our pipeline enables the quick selection of lenses for follow-up and further modeling, which significantly speeds up the construction of cosmography-grade models. This important step forward will help us to take advantage of the increase in the number of lenses that is expected in the coming decade, which is an increase of several orders of magnitude.

Surface figure measurement tool based on a radial shearing interferometer using a geometric phase lens with various spherical wavefronts.

We describe a compact radial shearing interferometer based on a geometric phase lens as a surface figure measurement tool. Based on the polarization and diffraction characteristics of a geometric phase lens, two radially sheared wavefronts are simply generated, and the surface figure of a specimen can be immediately reconstructed from the radial wavefront slope calculated with four phase-shifted interferograms obtained from a polarization pixelated complementary metal-oxide semiconductor camera. In order to increase the field of view, moreover, the incident wavefront is adjusted according to the shape of the target, which allows the reflected wavefront to become planar. By the combination of the incident wavefront formula and the measurement result by the proposed system, the whole surface figure of the target can be instantaneously reconstructed. As the experimental result, the surface figures of various optical components were reconstructed at the extended measurement area with less than 0.78µm deviations, and it was confirmed that the radial shearing ratio was fixed independent of the surface figures.

Projected-field kinetic Sunyaev-Zel'dovich Cross-correlations: halo model and forecasts

The kinetic Sunyaev-Zel'dovich (kSZ) effect, i.e., the Doppler boost of cosmic microwave background (CMB) photons caused by their scattering off free electrons in galaxy clusters and groups with non-zero bulk velocity, is a powerful window on baryons in the universe. We present the first halo-model computation of the cross-power spectrum of the “projected-field” kSZ signal with large-scale structure (LSS) tracers. We compare and validate our calculations against previous studies, which relied on N-body-calibrated effective formulas rather than the halo model. We forecast results for CMB maps from the Atacama Cosmology Telescope (AdvACT), Simons Observatory (SO), and CMB-S4, and LSS survey data from the Dark Energy Survey, the Vera C. Rubin Observatory (VRO), and Euclid. In cross-correlation with galaxy number density, for AdvACT × unWISE we forecast an 18σ projected-field kSZ detection using data already in hand. Combining SO CMB maps and unWISE galaxy catalogs, we expect a 62σ detection, yielding precise measurements of the gas density profile radial slopes. Additionally, we forecast first detections of the kSZ — galaxy weak lensing cross-correlation with AdvACT × VRO/Euclid (at 6σ) and of the kSZ — CMB weak lensing cross-correlation with SO (at 16σ). Finally, ≈ 10-20% precision measurements of the shape of the gas density profile should be possible with CMB-S4 kSZ — CMB lensing cross-correlation without using any external datasets.

An updated global survey of alluvial fans on Mars: Distinguishing alluvial fans from other fan-shaped features through morphologic characterization

Alluvial fans formed on Mars during the late Hesperian to early Amazonian in a climatic transition from a time of regular surface water activity to the current dry and cold climate. The depositional environments recorded by alluvial fans represent the final era of potential habitability on the Martian surface. Alluvial fan deposits can often look similar to deltaic or fluvial systems in visible remote sensing images but are formed in depositional and climatic environments that are distinct from those that lead to other radial depositional features. In order to better constrain regional and global depositional environments and further inform the analysis of the sedimentary history of Mars, we expanded the global catalog of alluvial fans on Mars by adding newly identified features and characterizing all new and previously identified features based on morphologic parameters. Using planform shape, radius, average radial slope, and radial profile shape, we classified features as alluvial fans, possible alluvial fans, and non-alluvial radial features (NARFs), based on how closely they fit the morphologic definition of alluvial fans. Other radial-shaped depositional features form in more water-rich depositional environments whereas alluvial fans form by subaerial deposition in arid to hyper arid environments from sporadic high-energy flow events interspersed with long dry periods of inactivity. By identifying new features and distinguishing alluvial fans from other fan-shaped features in the global catalog, we have isolated distinct depositional environments on a local scale and updated the global perspective of the distribution and variety of aqueous depositional environments during the early history of Mars. Newly identified alluvial fans are found as far as 78°S latitude as well as in numerous locations within the Hesperian to Noachian transition unit along the dichotomy and occur both in craters and along non-crater topographic features, expanding the global range of alluvial fan environments into regions that previously have been overlooked.

Role of the companion lensing galaxy in the CLASS gravitational lens B1152+199

ABSTRACT We reinvestigate the Cosmic Lens All-Sky Survey (CLASS) gravitational lens B1152+199 using archived Hubble Space Telescope (HST) data and Very Long Baseline Interferometry (VLBI) data. A consistent luminosity ratio within effective radius between the host galaxy and the X-galaxy is measured from HST tri-band images, which leads to a mass ratio between the two galaxies as rb ∼ 2. To determine the role of the X-galaxy in the lens system, we modelled the dual-lens system with constraints from the VLBI-resolved jet components and the HST images. The 8.4-GHz global-VLBI data currently provide the most stringent constraints to the mass model, especially to the radial power-law slope. The optimized models for this two-image three-component radio lens favour a steeper-than-isothermal inner slope. The jet bending in image B was also investigated and it turned out to be rather a misalignment than a curvature. The goodness-of-fit indicates that the role of the X-galaxy is crucial in the lens system if three pairs of resolved jet components are to be fitted. When we imported the optimal model from radio constraints to optical modelling with the HST tri-band data, the optimization kept the consistency of the optimal model and successfully reproduced the features observed in the HST images. This implies that the diffuse emission discovered in the HST images is actually a detection of the secondary lensing effects from the companion lens.

Radial Distribution of the Dust Comae of Comets 45P/Honda–Mrkos–Pajdus̆áková and 46P/Wirtanen

Abstract There was an unprecedented opportunity to study the inner dust coma environments, where the dust and gas are not entirely decoupled, of comets 45P/Honda–Mrkos–Pajdus̆áková (45P/HMP) from 2016 December 26 to 2017 March 15, and 46P/Wirtanen from 2018 November 10 to 2019 February 13, both in visible wavelengths. The radial profile slopes of these comets were measured in the R and HB-BC filters most representative of dust, and deviations from a radially expanding coma were identified as significant. The azimuthally averaged radial profile slope of comet 45P/HMP gradually changes from −1.81 ± 0.20 at 5.24 days preperihelion to −0.35 ± 0.16 at 74.41 days postperihelion. Contrastingly, the radial profile slope of 46P/Wirtanen stays fairly constant over the observed time period at −1.05 ± 0.05. Additionally, we find that the radial profile of 46P/Wirtanen is azimuthally dependent on the sky-plane-projected solar position angle, while that of 45P/HMP is not. These results suggest that comets 45P/HMP and 46P/Wirtanen have vastly different coma dust environments and that their dust expansion properties are distinct. As evident from these two comets, well-resolved inner comae are vital for detailed characterization of dust environments.

Internal dark matter structure of the most massive galaxy clusters since redshift 1

We investigate the evolution of the dark matter density profiles of the most massive galaxy clusters in the Universe. Using a ‘zoom-in’ procedure on a large suite of cosmological simulations of total comoving volume of 3 (h-1 Gpc)3, we study the 25 most massive clusters in four redshift slices from z ~ 1 to the present. The minimum mass is M500 > 5:5 × 1014 M⊙ at z = 1. Each system has more than two million particles within r500. Once scaled to the critical density at each redshift, the dark matter profiles within r500 are strikingly similar from z ~ 1 to the present day, exhibiting a low dispersion of 0.15 dex, and showing little evolution with redshift in the radial logarithmic slope and scatter. They have the running power law shape typical of the NFW-type profiles, and their inner structure, resolved to 3:8 h-1 comoving kpc at z = 1, shows no signs of converging to an asymptotic slope. Our results suggest that this type of profile is already in place at z > 1 in the highest-mass haloes in the Universe, and that it remains exceptionally robust to merging activity.

Coronal Density Measurements Using Giant Radio Pulses of the Crab Pulsar at the Cycle 24/25 Minimum

Accurate measurements of the coronal plasma density profile, which varies with the solar cycle (SC), are necessary to elucidate the solar wind acceleration. In this study, the Crab pulsar is observed using the 327 MHz radio telescope at the Toyokawa Observatory of the Institute for Space-Earth Environmental Research of Nagoya University to investigate the coronal plasma density profile for radial distances between 5 and 60 solar radii at the SC24/25 minimum. We derive the dispersion measures (DMs) that represent the integration of plasma density along the line of sight (LOS) for giant radio pulses of the Crab pulsar. We find that the observed DMs increased above the interstellar background level when the LOS for the Crab pulsar approached the Sun in mid-June 2018 and 2019. This increase in DM is attributed to the effect of the coronal plasma. We determine the plasma density distribution by fitting a spherically symmetric model to the observed DM data. The flat radial slopes of the best-fit model are consistent with pulsar observations in the low-activity periods of past SCs, and they are attributed to the effect of the coronal hole over the south pole of the Sun. Our results show that the density level near the Sun is similar to those observed in the low activity periods of past SCs, implying recovery of the coronal plasma density from a significant reduction at the SC23/24 minimum.

Radiographic assessment of carpal conformation in the horse: Technique development and validation of the consistency of measurements.

Carpal conformation is often considered as a contributory factor to performance and lameness in the horse; however, few attempts have been made to objectively measure radiographic variations of carpal conformation in horses due to insufficient measurable carpal parameters. This pilot study used carpal radiographic images acquired from 10 cadaveric equine forelimbs transected at the antebrachial midshaft from 7 adult horses (7.2±2.6years), positioned at 'zero lateromedial' (ZLM) and 'zero dorsopalmar' (ZDP) views, to investigate the anatomy of the equine carpus and develop parameters that could be objectively used to assess carpal conformation in horses. Dorsal carpal angle (DCA: 176.61±0.66º), distal radial slope carpal angle (DRSCA: 145.59±2.19º), intermediate carpal bone proximal tuberosity-radial angle (CiPxTRA: 115.69±3.15º) and third carpal bone palmar facet angle (C3PalFCA: 84.43±1.13º) were all developed from the ZLM view while medial carpal angle (MCA: 183.34±1.02º), disto-dorsal slope angle of the third carpal bone (C3DDSA: 8.27±0.92º) and width ratio of distal radius to proximal metacarpus (WDR:WPM=1.13±0.03) were 3 of the 10 parameters developed from the ZDP view. Easy to identify and measurable parameters will help to provide quantitative assessment of carpal conformation in the horse with potential of eliminating subjective observational variation errors between clinicians. These newly developed parameters will be useful in further studies to measure variations in the conformation of the equine carpus in live horses and comparison between subjective visual assessment and objective radiographic evaluation methods.

Short-Circuit Electromagnetic Force Distribution Characteristics in Transformer Winding Transposition Structures

For continuous or spiral windings which feature multiple continuously transposed conductors (CTC) wound in parallel, the transposition structure is commonly used to suppress circulation between conductors. This introduces a local asymmetry in transformer windings. Fault analyses have shown that building an asymmetric structure in transformers increases deformation risk in these windings. Researchers have yet to fully investigate this asymmetric structure. This study was conducted to observe the influence of transposition structure in a 110 kV transformer. The conductor's relative position forms three patterns during the transposition process; two parameters are established to describe the position-changing process. A finite-element method (FEM) model is built to investigate the magnetic field and electromagnetic force distributions. The results indicate that the transposition structure distorts the magnetic field distribution. The maximum distortion factor of the axial component of magnetic flux density (B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> ) along the axial direction caused by the transposition structure is 14.6%. The transposition structure only changes the radial change slope of B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> . The gap caused by the transposition process aggravates imbalance in the ampere-turns distribution, increasing the amplitude of the radial component of magnetic flux density (B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ) at the middle height of the transformer low voltage (LV) winding. The maximum amplitude of B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> at the transposition structure increases by 513%. The Lorentz force over the CTCs remains constant from before to after the transposition process, though its linear density over the CTCs is unevenly distributed throughout. The axial component F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> varies from -31 to 10 kN/m, while the radial component F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> varies from -146 to -51 kN/m. The results show that the initial stage of the CTC height rising segment is a weak point and should be strengthened in the manufacturing process.

Effect of pebble flux-regulated planetesimal formation on giant planet formation

Context. The formation of gas giant planets by the accretion of 100 km diameter planetesimals is often thought to be inefficient. A diameter of this size is typical for planetesimals and results from self-gravity. Many models therefore use small kilometer-sized planetesimals, or invoke the accretion of pebbles. Furthermore, models based on planetesimal accretion often use the ad hoc assumption of planetesimals that are distributed radially in a minimum-mass solar-nebula way. Aims. We use a dynamical model for planetesimal formation to investigate the effect of various initial radial density distributions on the resulting planet population. In doing so, we highlight the directive role of the early stages of dust evolution into pebbles and planetesimals in the circumstellar disk on the subsequent planet formation. Methods. We implemented a two-population model for solid evolution and a pebble flux-regulated model for planetesimal formation in our global model for planet population synthesis. This framework was used to study the global effect of planetesimal formation on planet formation. As reference, we compared our dynamically formed planetesimal surface densities with ad hoc set distributions of different radial density slopes of planetesimals. Results. Even though required, it is not the total planetesimal disk mass alone, but the planetesimal surface density slope and subsequently the formation mechanism of planetesimals that enables planetary growth through planetesimal accretion. Highly condensed regions of only 100 km sized planetesimals in the inner regions of circumstellar disks can lead to gas giant growth. Conclusions. Pebble flux-regulated planetesimal formation strongly boosts planet formation even when the planetesimals to be accreted are 100 km in size because it is a highly effective mechanism for creating a steep planetesimal density profile. We find that this leads to the formation of giant planets inside 1 au already by pure 100 km planetesimal accretion. Eventually, adding pebble accretion regulated by pebble flux and planetesimal-based embryo formation as well will further complement this picture.

Integral-equation approach to resonances in circular two-layer flows around an island with bottom topography

This paper presents an integral-equation approach to the linear instability problem of two-layer quasi-geostrophic flows around circular islands with radial offshore bottom slope. The flows are composed of concentric uniform potential-vorticity (PV) rings in each layer, with the PV of each ring being opposite in sign. The study extends an earlier similar barotropic model and focuses on the degree to which the topographic waves resonate with the deformation waves at the rings’ peripheries. The integral approach poses the instability problem in a physically elucidating way, whereby the resonating waves in the system are directly identified. Four types of instabilities are identified: instability caused by the resonance of waves at the liquid contours at the edge of each PV ring, instability caused by the resonance of the wave at the upper-layer contour and the topographic waves outside the lower-layer contour, a similar resonance of the lower-layer contour with the topographic waves, and a resonance between one of the eigenmodes of the contour subsystem with the topographic waves. The three latter resonances lead to critical layer instabilities and can be identified as resonances between the contour waves and a collection of singular topographic modes with a critical layer. The PV perturbations in the outer region can be represented asymptotically (far from the origin) as a combination of barotropic and baroclinic modes. Usually, the asymptotically barotropic mode is the mode in resonance with the contours, but, for small growth rates, the asymptotically baroclinic mode may be the dominant mode.

Spatiotemporal remodeling of embryonic aortic arch: stress distribution, microstructure, and vascular growth in silico.

The microstructure for mature vessels has been investigated in detail, while there is limited information about the embryonic stages, in spite of their importance in the prognosis of congenital heart defects. It is hypothesized that the embryonic vasculature represents a disorganized but dynamic soft tissue, which rapidly evolves toward a specialized multi-cellular vascular structure under mechanical loading. Here the microstructural evolution process of the embryonic pharyngeal aortic arch structure was simulated using an in ovo validated long-term growth and remodeling computational model, implemented as an in-house FEBio plug-in. Optical coherence tomography-guided servo-null pressure measurements are assignedas boundary conditions through the critical embryonic stages. The accumulation of key microstructural constituents was recorded through zoom confocal microscopy for all six embryonic arch arteriessimultaneously. The total amount and the radial variation slope of the collagen along the arch wall thickness in different archtypes and for different embryonic times, with different dimension scales, were normalized and compared statistically. The arch growth model shows that the stress levels around the lumen boundary increase from [Formula: see text] (Stage 18) to a level higher than [Formula: see text] (Stage 24), depending on matrix constituent production rates, while the homeostatic strain level is kept constant. The statistical tests show that although the total collagen levels differentiate among bilateral positions of the same arch, the shape coefficient of the matrix microstructural gradient changes with embryonic time, proving radial localization, in accordance with numerical model results. In vivo cell number (DAPI) and vascular endothelial growth factor distributions followed similar trends.

Formation of single-moon systems around gas giants

Context. Several mechanisms have been proposed to explain the formation process of satellite systems, and relatively large moons are thought to be born in circumplanetary disks. Making a single-moon system is known to be more difficult than multiple-moon or moonless systems. Aims. We aim to find a way to form a system with a single large moon, such as Titan around Saturn. We examine the orbital migration of moons, which change their direction and speed depending on the properties of circumplanetary disks. Methods. We modeled dissipating circumplanetary disks with taking the effect of temperature structures into account and calculated the orbital evolution of Titan-mass satellites in the final evolution stage of various circumplanetary disks. We also performed N-body simulations of systems that initially had multiple satellites to see whether single-moon systems remained at the end. Results. The radial slope of the disk-temperature structure characterized by the dust opacity produces a patch of orbits in which the Titan-mass moons cease inward migration and even migrate outward in a certain range of the disk viscosity. The patch assists moons initially located in the outer orbits to remain in the disk, while those in the inner orbits fall onto the planet. Conclusions. We demonstrate for the first time that systems can form that have only one large moon around giant planet. Our N-body simulations suggest satellite formation was not efficient in the outer radii of circumplanetary disks.

Sedimentation in a Rifted Basin: Insights from the Proterozoic Rajgarh Siliciclastics, Delhi Supergroup, Northeastern Rajasthan

Abstract The fining upward sequence of Proterozoic Rajgarh Formation mainly consists of feldspathic sandstone, quartzarenite, bands of shale and have a restricted lateral extent with variable palaeoflow pattern. Eight major lithofacies identified from this succession collectively indicate fluvial to marginal marine depositional set up. The Rajgarh quartzose to feldspatho-quartzose siliciclastics are fine- to coarse grained, poorly- to moderately sorted derived from a stable continental block provenance that deposited in a fault bounded graben. The deposition of the Rajgarh siliciclastics can be best explained by short transportation, high relief and fast sedimentation in rapidly subsiding fault-bounded basin and indicate radial slope and source located in the Dausa uplift in the east and banded gneissic complex (BGC) in the south and southeast.

The Multi-object Spectroscopy Observation of Seven Interacting Galaxy Pairs: Metallicity Gradients and Star Formation Distributions

We use the Multi-Object Spectroscopy system of Xinglong 2.16 m telescope to study the gradients of gas-phase oxygen abundance and the distributions of star formation activities of seven nearby interacting galaxy pairs. On the basis of emission line luminosities and flux ratios, we estimate the gas-phase metallicities (log(O/H)), excitation mechanisms, and star formation rates (SFRs) of different regions in each galaxy. The average radial slope of log(O/H) from linear fitting of galaxy pairs in our sample is significantly flatter than that of isolated disk galaxies, also the central metallicity is much lower for interacting galaxies. This supports the predictions and results of previous theoretical numerical simulations and observational works which show the cold gas inflows induced by galaxy interactions can dilute the central metallicity. From the analysis of the radial distribution of SFR surface densities (ΣSFR), we find that, in our sample, galaxies in Spiral–Spiral (S+S) pairs have peak ΣSFR at the center region and lower SFRs at the outer parts than that at the center. On the other hand, for two spirals in Spiral-Elliptical (S+E) pairs (Arp142 and J0338+2120), they both have relatively higher (ΣSFR) in their off-nuclei regions. This may hint a dependence of star formation distributions for paired galaxies on their companion morphologies.

Is Fixation With K-Wire Sufficient In Distal Radioulnar Joint Instability Accompanying The Distal Radius Fracture?

Introduction: Distal radius fractures are the most common fractures of the upper extremity. Recently, the tendency towards surgical treatment has increased in distal radius fractures. Distal radioulnar joint instability is thought to negatively affect the results of distal radius fracture. Our aim in this study is to compare the patients with and without distal radioulnar joint instability, who were operated with the diagnosis of distal radius fracture, clinically and radiologically. Materials and methods: 31 patients who were operated with the diagnosis of distal radius fracture and whose fracture union was completed were included in the study. Patients with an isolated distal radius fracture (19 individuals) were called group 1, while patients with a distal radioulnar joint instability accompanying the distal radius fracture (12 individuals) were called group 2. The groups were compared functionally with DASH and MAYO scores in terms of pain and radiologically with VAS score in terms of radial length, radial slope and volar slope. Joint range of motion was also measured with a standard goniometer and compared between the groups. Results: In the group with isolated distal radius fractures, 11 (57.9%) patients were male and 8 (42.1%) were female. The mean length of follow-up was 22.5 months. In the group with distal radius fractures and accompanying distal radioulnar joint instability, 9 (75.0%) patients were male and 3 (25.0%) were female. The mean length of follow-up in this group was 27.08 months. There was no difference between MAYO, DASH and VAS scores between the groups (p>0.05). The mean radial length was 9.95 ± 1.96 (6; 14) in group 1 and 10.67 ± 2.71 (4; 15) in group 2. The mean radial slope was 19.53 ± 2.78 (14; 26) in group 1 and 18.92 ± 3.6 (11; 26) in group 2. The mean volar slope was 8.32 ± 3.59 in group 1 and 6.92 ± 4.81 (-2; 14) in group 2. It was understood that there was no significant difference between the groups (p>0.05). While the mean supination angle was 80.53 ± 6.64 (60; 90) in group 1, it was 85.42 ± 5.42 (75; 90) in group 2, and it was found to be significantly higher in group 2 (p