Fundamental properties of the pre-main sequence eclipsing stars of MML 53 and the mass of the tertiary

We present the most comprehensive analysis to date of the Upper Centaurus Lupus eclipsing binary MML 53 (with PEB = 2.097892 d), and for the first time, confirm the bound-nature of the third star (in a P3 ∼ 9 yr orbit) by constraining its mass dynamically. Our analysis is based on new and archival spectra and time-series photometry, spanning 80% of one orbit of the outer component. From the spectroscopic analysis, we determined the temperature of the primary star to be 4880 ± 100 K. The study of the close binary incorporated treatment of spots and dilution by the tertiary in the light curves, allowing for the robust measurement of the masses of the eclipsing components within 1% (M1 = 1.0400 ± 0.0067 M⊙ and M2 = 0.8907 ± 0.0058 M⊙), their radii within 4.5% (R1 = 1.283 ± 0.043 R⊙ and R2 = 1.107 ± 0.049 R⊙), and the temperature of the secondary star (Teff, 2 = 4379 ± 100 K). From the analysis of the eclipse timings, and the change in systemic velocity of the eclipsing binary and the radial velocities of the third star, we measured the mass of the outer companion to be 0.7 M⊙ (with a 20% uncertainty). The age we derived from the evolution of the temperature ratio between the eclipsing components is fully consistent with previous, independent estimates of the age of Upper Centaurus Lupus (16 ± 2 Myr). At this age, the tightening of the MML 53 eclipsing binary has already occurred, thus supporting close-binary formation mechanisms that act early in the stars’ evolution. The eclipsing components of MML 53 roughly follow the same theoretical isochrone, but appear to be inflated in radius (by 20% for the primary and 10% for the secondary) with respect to recent evolutionary models. However, our radius measurement of the 1.04 M⊙ primary star of MML 53 is in full agreement with the independent measurement of the secondary of NP Per which has the same mass and a similar age. The eclipsing stars of MML 53 are found to be larger but not cooler than predicted by non-magnetic models, it is not clear what is the mechanism that is causing the radius inflation given that activity, spots and/or magnetic fields slowing their contraction, require the inflated stars to be cooler to remain in thermal equilibrium.

Fundamental properties of the pre-main sequence eclipsing stars of MML 53 and the mass of the tertiary

We present the most comprehensive analysis to date of the Upper Centaurus Lupus eclipsing binary MML 53 (with PEB = 2.097892 d), and for the first time, confirm the bound-nature of the third star (in a P3 ∼ 9 yr orbit) by constraining its mass dynamically. Our analysis is based on new and archival spectra and time-series photometry, spanning 80% of one orbit of the outer component. From the spectroscopic analysis, we determined the temperature of the primary star to be 4880 ± 100 K. The study of the close binary incorporated treatment of spots and dilution by the tertiary in the light curves, allowing for the robust measurement of the masses of the eclipsing components within 1% (M1 = 1.0400 ± 0.0067 M⊙ and M2 = 0.8907 ± 0.0058 M⊙), their radii within 4.5% (R1 = 1.283 ± 0.043 R⊙ and R2 = 1.107 ± 0.049 R⊙), and the temperature of the secondary star (Teff, 2 = 4379 ± 100 K). From the analysis of the eclipse timings, and the change in systemic velocity of the eclipsing binary and the radial velocities of the third star, we measured the mass of the outer companion to be 0.7 M⊙ (with a 20% uncertainty). The age we derived from the evolution of the temperature ratio between the eclipsing components is fully consistent with previous, independent estimates of the age of Upper Centaurus Lupus (16 ± 2 Myr). At this age, the tightening of the MML 53 eclipsing binary has already occurred, thus supporting close-binary formation mechanisms that act early in the stars’ evolution. The eclipsing components of MML 53 roughly follow the same theoretical isochrone, but appear to be inflated in radius (by 20% for the primary and 10% for the secondary) with respect to recent evolutionary models. However, our radius measurement of the 1.04 M⊙ primary star of MML 53 is in full agreement with the independent measurement of the secondary of NP Per which has the same mass and a similar age. The eclipsing stars of MML 53 are found to be larger but not cooler than predicted by non-magnetic models, it is not clear what is the mechanism that is causing the radius inflation given that activity, spots and/or magnetic fields slowing their contraction, require the inflated stars to be cooler to remain in thermal equilibrium.

Post–Vacuum-Assisted Stereotactic Core Biopsy Clip Displacement: A Comparison between Commercially Available Clips and Surgical Clip

Purpose The placement of localization clips following percutaneous biopsy is a standard practice for a variety of situations. Subsequent clip displacement creates challenges for imaging surveillance and surgical planning, and may cause confusion amongst radiologists and between surgeons and radiologists. Many causes have been attributed for this phenomenon including the commonly accepted “accordion effect.” Herein, we investigate the performance of a low cost surgical clip system against 4 commercially available clips. Methods We retrospectively reviewed 2112 patients who underwent stereotactic vacuum-assisted core biopsy followed by clip placement between January 2013 and June 2016. The primary performance parameter compared was displacement >10 mm following vacuum-assisted stereotactic core biopsy. Within the group of clips that had displaced, the magnitude of displacement was compared. Results There was a significant difference in displacement among the clip types ( P < .0001) with significant pairwise comparisons between pediatric surgical clips and SecureMark (38% vs 28%; P = .001) and SenoMark (38% vs 27%; P = .0001) in the proportion displaced. The surgical clips showed a significant magnitude of displacement of approximately 25% greater average distance displaced. Conclusions As a whole, the commercial clips performed better than the surgical clip after stereotactic vacuum-assisted core biopsy suggesting the surrounding outer component acts to anchor the central clip and minimizes clip displacement. The same should apply to tomosynthesis-guided biopsy.

The primordial helium abundance determination using multicomponent photoionization modelling of low-metallicity H II regions

The method for the multicomponent photoionization modelling (MPhM) of low-metallicity H II regions surrounding the starburst region was developed. The internal structure of the H II region has been determined using the evolutionary modelling of the superwind bubble surrounding the star-forming region. Models of Chevalier and Clegg (1985) and Weaver et al. (1977) have been used to determine the radial distribution of the gas density, the velocity of gas layers, and the temperature within internal components (the region of the superwind free expansion and the cavity, respectively). The chemical abundances in region of the superwind free expansion were obtained from the evolutionary population synthesis with including of rotating stars. The chemical abundances within cavity were defined by averaging over mass the chemical compositions of mixture of the abundances of gas from superwind and ones within outer component, because of gas evaporation from external component into the cavity. External components of our models describe a high-density, thin shell of gas formed by superwind shock and a typical undisturbed hydrodynamically H II region, respectively. Evolutionary grids of multicomponent low-metallicity models are calculated. A comparative analysis of the results of their calculation with the observed data has been carried out. The ionic abundances averaged over modelling volume as well as chemical composition assumed in models were used to derive the new expressions for ionization-correction factors that were used to redetermine the chemical compositions of 88 H II regions in blue compact dwarf galaxies. It must be noticed that we used for this propose the ionic abundances obtained by Izotov et al. (2007). In result the primordial helium abundance and its enrichment during stellar chemical evolution of matter were determined.

The halo of M49 and its environment as traced by planetary nebulae

We investigate the stellar halo of the nearby elliptical Virgo-cluster galaxy M49 using Planetary Nebulae (PNe). M49 is the second-brightest galaxy of the Virgo cluster and is at the center of the Virgo subcluster B. We present an extended catalogue extracted from a narrow-band survey carried out with Subaru’s Suprime Cam, consisting of 735 PNe down to a limiting magnitude of m5007 = 29.3. This PNe population traces the halo out to 155 kpc from the galaxy’s center, which provides accurate measurement of the luminosity-specific PN-number (α-parameter) in the inner and outer regions of M49’s halo. We are also able to determine the morphological variation of the planetary nebulae luminosity function (PNLF), that may trace different parent stellar populations. This enables us to identify the transition from the PN-scarce, possibly metal-rich, galaxy halo to the PN-rich, metal-poor, outer component.

CotG-Like Modular Proteins Are Common among Spore-Forming Bacilli

ABSTRACTCotG is an abundant protein initially identified as an outer component of theBacillus subtilisspore coat. It has an unusual structure characterized by several repeats of positively charged amino acids that are probably the outcome of multiple rounds of gene elongation events in an ancestral minigene. CotG is not highly conserved, and its orthologues are present in only twoBacillusand twoGeobacillusspecies. InB. subtilis, CotG is the target of extensive phosphorylation by a still unidentified enzyme and has a role in the assembly of some outer coat proteins. We report now that most spore-forming bacilli contain a protein not homologous to CotG ofB. subtilisbut sharing a central “modular” region defined by a pronounced positive charge and randomly coiled tandem repeats. Conservation of the structural features in most spore-forming bacilli suggests a relevant role for the CotG-like protein family in the structure and function of the bacterial endospore. To expand our knowledge on the role of CotG, we dissected theB. subtilisprotein by constructing deletion mutants that express specific regions of the protein and observed that they have different roles in the assembly of other coat proteins and in spore germination.IMPORTANCECotG ofB. subtilisis not highly conserved in theBacillusgenus; however, a CotG-like protein with a modular structure and chemical features similar to those of CotG is common in spore-forming bacilli, at least when CotH is also present. The conservation of CotG-like features when CotH is present suggests that the two proteins act together and may have a relevant role in the structure and function of the bacterial endospore. Dissection of the modular composition of CotG ofB. subtilisby constructing mutants that express only some of the modules has allowed a first characterization of CotG modules and will be the basis for a more detailed functional analysis.

Contrasting magma emplacement mechanisms within the Rogart igneous complex, NW Scotland, record the switch from regional contraction to strike-slip during the Caledonian orogeny

The Rogart igneous complex is unique within the northern Scottish Caledonides because it comprises an apparent continuum of magma types that records a progressive change in emplacement mechanisms related to large-scale tectonic controls. Syn-D2 leucogranites and late-D2 quartz monzodiorites were emplaced during crustal thickening and focused within the broad zone of ductile deformation associated with the Naver Thrust. In contrast, emplacement of the post-D2 composite central pluton was controlled by development of a steeply dipping dextral shear zone along the Loch Shin Line, interpreted as an anti-Riedel shear within the Great Glen Fault system. The mantle-derived nature of the late-to-post-D2 melts implies that the Naver Thrust and the Loch Shin Line were both crustal-scale structures along which magmas were channelled during deformation. A U–Pb zircon age of 425±1.5 Ma for the outer component of the central pluton provides an upper limit on regional deformation and metamorphism within host Moine rocks. These findings are consistent with the view that a fundamental change in tectonic regime occurred in the Scottish Caledonides at c. 425 Ma, corresponding to the switch from regional thrusting that resulted from the collision of Baltica and Laurentia, to the development of the orogen-parallel Great Glen Fault system.

Planetary nebulae and determination of the bulge–disk boundary

In this paper, a sample of planetary nebulae in the Galaxy's inner-disk and bulge is used to find the galactocentric distance that optimally separates these two populations in terms of their abundances. Statistical distance scales were used to investigate the distribution of abundances across the disk–bulge interface, while a Kolmogorov–Smirnov test was used to find the distance at which the chemical properties of these regions separate optimally. The statistical analysis indicates that, on average, the inner population is characterized by lower abundances than the outer component. Additionally, for the α-element abundances, the inner population does not follow the disk's radial gradient toward the Galactic Center. Based on our results, we suggest a bulge–disk interface at 1.5 kpc, marking the transition between the bulge and the inner disk of the Galaxy as defined by the intermediate-mass population.

Stress Relaxation Analysis of Polyurethane Foam Preloaded Structures

Based on the nonlinear finite element analysis method, FEA models which describe the viscoelastic friction contact state of the polyurethane foam preloaded structures are created. In the simulations, the general Maxwell viscoelastic constitutive relation is introduced and a seven-parameter general Maxwell viscoelastic model is used to fit the experimental stress relaxation curve of polyurethane foam. During the nonlinear contact analysis, coulomb friction law is adopted, and the effects of the coulomb friction coefficient on the reaction force in the axial direction are analyzed. The FE results show that the change tendencies of relation curves of the structures are similar to which of the polyurethane foams. In the end, the influences of stiffness ratio of polyurethane foam to the outer component on the structural relaxed force are discussed, and the FE results indicate that the stiffness ratios affect the stress (force) relaxation degree remarkably. That is to say a good structure design could optimize the mechanical performance of the complicated structures greatly.

Molecular genetic and anatomical characterization of potato tuber skin appearance

Potato (Solanum tuberosum L.) skin is composed of suberized phellem cells, the outer component of the tuber periderm. The focus of the proposed research was to apply genomic approaches to identify genes that control tuber skin appearance - smooth and shiny skin is highly preferred by the customers while russeted/netted skin potatoes are rejected. The breeding program (at Cornell University) seeks to develop smooth-skin varieties but has encountered frequent difficulties as inheritance of russeting involves complementary action by independently segregating genes, where a dominant allele at each locus is required for any degree of skin russeting. On the other hand, smooth-skin varieties frequently develop unsightly russeting in response to stress conditions, mainly high soil temperatures. Breeding programs in Israel aimed towards the improvement of heat tolerant varieties include skin quality as one of the desired characteristics. At the initiation of the present project it was unclear whether heat induced russeting and genetically inherited russeting share the same genes and biosynthesis pathways. Nevertheless, it has been suggested that russeting might result from increased periderm thickness, from strong cohesion between peridermal cells that prevents the outer layers from sloughing off, or from altered suberization processes in the skin. Hence, the original objectives were to conduct anatomical study of russet skin development, to isolate skin and russeting specific genes, to map the loci that determine the russet trait, and to compare with map locations the candidate russet specific genes, as well as to identify marker alleles that associated with russet loci. Anatomical studies suggested that russet may evolve from cracking at the outer layers of the skin, probably when skin development doesn’t meet the tuber expansion rate. Twodimensional gel electrophoresis and transcript profiling (cDNA chip, potato functional genomic project) indicated that in comparison to the parenchyma tissue, the skin is enriched with proteins/genes that are involved in the plant's responses to biotic and abiotic stresses and further expand the concept of the skin as a protective tissue containing an array of plantdefense components. The proteomes of skin from heat stressed tubers and native skin didn’t differ significantly, while transcript profiling indicated heat-related increase in three major functional groups: transcription factors, stress response and protein degradation. Exceptional was ACC synthase isogene with 4.6 fold increased level in the heat stressed skin. Russeting was mapped to two loci: rusB on chromosome 4 and rusC on chromosome 11; both required for russeting. No evidence was found for a third locus rusA that was previously proposed to be required for russeting. In an effort to find a link between the russeting character and the heat-induced russeting an attempt was made to map five genes that were found in the microarray experiment to be highly induced in the skin under heat stress in the segregating russet population. Only one gene was polymorphic; however it was localized to chromosome 2, so cannot correspond to rusB or rusC. Evaluation of AFLP markers tightly linked to rusB and rusC showed that these specific alleles are not associated with russeting in unrelated germplasm, and thus are not useful for MAS per se. To develop markers useful in applied breeding, it will be necessary to screen alleles of additional tightly linked loci, as well as to identify additional russet (heat-induced and/or native) related genes.