Components A2 Research Articles

Characteristics of oxytetracycline stress-sensitive microbe-dissolved organic matter component interactions during composting

Dissolved organic matter (DOM) has important impacts on the transportation of antibiotics through chemical and biological processes in composting. The interaction between DOM and antibiotics is reciprocal. The interaction between DOM ligands and antibiotics could be characterized based on a technique combining parallel factor analysis (PARAFAC) and microbial community structure analysis. However, PARAFAC cannot reveal the dynamic changes in each DOM peak in one PARAFAC component under antibiotic stress. In this study, two-dimensional correlation spectroscopy (2DCOS) combined with PARAFAC and bacterial community diversity analyses were employed to reveal the effects of oxytetracycline (OTC) stress and the key microorganisms on the transformation of different fluorescent peaks from DOM PARAFAC components during chicken manure composting. The results showed that OTC inhibits the transformation between DOM PARAFAC components by inhibiting the core microbial activities involved in the transformation of DOM components. Protein-like components (C1 and C2) were more sensitive to OTC residue, and components with a high humification degree promoted the degradation of OTC. The interaction between special DOM PARAFAC components and certain bacteria affects the degradation of OTC. The DOM PARAFAC components A2(C1), B1(C2), B2(C2) and Z1(C4) enhanced OTC degradation by stimulating the genera Pseudomonas, Glycomyces and Hyphomicrobium. With these promising results, the true effect of DOM PARAFAC components on the degradation of OTC can be revealed, which is helpful for addressing antibiotic contamination to improve the bioavailability of compost products.

FAUST VI. VLA1623−2417 B: a new laboratory for astrochemistry around protostars on 50 au scale

ABSTRACT The ALMA (Atacama Large Millimeter Array) interferometer, with its unprecedented combination of high sensitivity and high angular resolution, allows for (sub-)mm wavelength mapping of protostellar systems at Solar system scales. Astrochemistry has benefitted from imaging interstellar complex organic molecules in these jet–disc systems. Here, we report the first detection of methanol (CH3OH) and methyl formate (HCOOCH3) emission towards the triple protostellar system VLA1623−2417 A1+A2+B, obtained in the context of the ALMA Large Programme FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars). Compact methanol emission is detected in lines from Eu = 45 K up to 61 K and 537 K towards components A1 and B, respectively. Large velocity gradient analysis of the CH3OH lines towards VLA1623−2417 B indicates a size of 0.11–0.34 arcsec (14–45 au), a column density $N_{\rm CH_3OH}$ = 1016–1017 cm−2, kinetic temperature ≥ 170 K, and volume density ≥ 108 cm−3. A local thermodynamic equilibrium approach is used for VLA1623−2417 A1, given the limited Eu range, and yields Trot ≤ 135 K. The methanol emission around both VLA1623−2417 A1 and B shows velocity gradients along the main axis of each disc. Although the axial geometry of the two discs is similar, the observed velocity gradients are reversed. The CH3OH spectra from B show two broad (4–5 km s−1) peaks, which are red- and blueshifted by ∼ 6–7 km s−1 from the systemic velocity. Assuming a chemically enriched ring within the accretion disc, close to the centrifugal barrier, its radius is calculated to be 33 au. The methanol spectra towards A1 are somewhat narrower (∼ 4 km s−1), implying a radius of 12–24 au.

Frequency shift of an optical frequency standard as a function of probe modulation of the radiation frequency, pressure, and gas temperature in an absorbing cell

Frequency shifts of an optical Nd : YAG/I2-standard are measured in a pressure range of molecular iodine 5 – 22 mTorr and deviation of probe modulation frequency 480 kHz – 4 MHz for the hyperfine structure component a1 of the molecular iodine absorption line R(56) 32 – 0. The frequency shift of the optical standard is estimated under varied temperatures of a cell and cell finger, which determines the pressure of the molecular iodine vapour. The requirements are defined to temperature stability of the cell and its finger for obtaining high long-term frequency stability of the optical frequency standard.

Black hole perturbations in vector-tensor theories: the odd-mode analysis

In generalized Proca theories with vector-field derivative couplings, a bunch of hairy black hole solutions have been derived on a static and spherically symmetric background. In this paper, we formulate the odd-parity black hole perturbations in generalized Proca theories by expanding the corresponding action up to second order and investigate whether or not black holes with vector hair suffer ghost or Laplacian instabilities. We show that the models with cubic couplings G3(X), where X=−AμAμ/2 with a vector field Aμ, do not provide any additional stability condition as in General Relativity. On the other hand, the exact charged stealth Schwarzschild solution with a nonvanishing longitudinal vector component A1, which originates from the coupling to the Einstein tensor GμνAμ Aν equivalent to the quartic coupling G4(X) containing a linear function of X, is unstable in the vicinity of the event horizon. The same instability problem also persists for hairy black holes arising from general quartic power-law couplings G4(X) ⊃ β4 Xn with the nonvanishing A1, while the other branch with A1=0 can be consistent with conditions for the absence of ghost and Laplacian instabilities. We also discuss the case of other exact and numerical black hole solutions associated with intrinsic vector-field derivative couplings and show that there exists a wide range of parameter spaces in which the solutions suffer neither ghost nor Laplacian instabilities against odd-parity perturbations.

Utjecaj navodnjavanja i gnojidbe du�ikom na urod i komponente uroda zrna kukuruza (Zea mays L.)

Grain yield of maize is mostly affected by amount of available water and nitrogen and correlated to yield components. In this 2-years study the influence of different irrigation water amounts (a1=rainfed; a2=60-100% field water capacity (FWC); a3=80-100% FWC), nitrogen fertilizer levels (b1=0 kg*N*ha-1; b2=100 kg*N*ha-1; b3=200 kg*N*ha-1) and hybrids (c1=OSSK515; c2=OS5997; c3=OS5775; c4=OS5885) on grain yield and yield components was tested. Furthermore the correlation analysis as well as direct and indirect path coefficients were used to analyse the connection between yield and yield components (grain number/cob, grain weight, 1000 grain weight, cob length, cob weight) across tested treatments. The influence of all tested factors was significant (P<0.05) in both years of study. Specific study results were obtained in extremely wet year 2010 when irrigation water reduced grain yield and yield components (a1=9.9; a2=8.8; a3=7.8 t*ha-1). Opposite to year 2013 when irrigation water increased grain yield as well as yield components (a1=8.9; a2=9.7; a3=10.3 t*ha-1). Nitrogen fertilizer was significant to all tested variables in both years of the study (b1=5.7; b2=9.2; b3=11.7 t*ha-1 in 2010 and b1=6.3; b2=8.9; b3=10.6 t*ha-1 in 2013). Generally, the greatest amount of nitrogen fertilizer the larger yield or yield components are achieved. The influence of hybrid was significant for all tested variables with exemption to 1000 grain weight and grain weight/cob during growing season 2013. In both years of the study hybrid c2 OS5997 achieved the highest yield as well as yield components. Correlation analysis showed strong positive correlation between yield and cob weight (r=0.77 (2010); r=0.84 (2013)) what is confirmed with direct and indirect path analysis test.

Serum reactome induced by Bordetella pertussis infection and Pertussis vaccines: qualitative differences in serum antibody recognition patterns revealed by peptide microarray analysis.

BackgroundPertussis (whooping cough) remains a public health problem despite extensive vaccination strategies. Better understanding of the host-pathogen interaction and the detailed B. pertussis (Bp) target recognition pattern will help in guided vaccine design. We characterized the specific epitope antigen recognition profiles of serum antibodies (‘the reactome’) induced by whooping cough and B. pertussis (Bp) vaccines from a case–control study conducted in 1996 in infants enrolled in a Bp vaccine trial in Sweden (Gustafsson, NEJM, 1996, 334, 349–355).MethodsSera from children with whooping cough, vaccinated with Diphtheria Tetanus Pertussis (DTP) whole-cell (wc), acellular 5 (DPTa5), or with the 2 component (a2) vaccines and from infants receiving only DT (n = 10 for each group) were tested with high-content peptide microarrays containing 17 Bp proteins displayed as linear (n = 3175) peptide stretches. Slides were incubated with serum and peptide-IgG complexes detected with Cy5-labeled goat anti-human IgG and analyzed using a GenePix 4000B microarray scanner, followed by statistical analysis, using PAM (Prediction Analysis for Microarrays) and the identification of uniquely recognized peptide epitopes.Results367/3,085 (11.9%) peptides were recognized in 10/10 sera from children with whooping cough, 239 (7.7%) in DTPwc, 259 (8.4%) in DTPa5, 105 (3.4%) DTPa2, 179 (5.8%) in the DT groups. Recognition of strongly recognized peptides was similar between whooping cough and DPTwc, but statistically different between whooping cough vs. DTPa5 (p < 0.05), DTPa2 and DT (p < 0.001 vs. both) vaccines. 6/3,085 and 2/3,085 peptides were exclusively recognized in (10/10) sera from children with whooping cough and DTPa2 vaccination, respectively. DTPwc resembles more closely the whooping cough reactome as compared to acellular vaccines.ConclusionWe could identify a unique recognition signature common for each vaccination group (10/10 children). Peptide microarray technology allows detection of subtle differences in epitope signature responses and may help to guide rational vaccine development by the objective description of a clinically relevant immune response that confers protection against infectious pathogens.Electronic supplementary materialThe online version of this article (doi:10.1186/s12865-015-0090-3) contains supplementary material, which is available to authorized users.

Determining the time delays in the gravitational lens PG 1115+080

A statistical analysis of published long-term photometric monitoring observations of the gravitationally lensed quasar PG 1115+080 in the optical is presented. This goal of this study is determining the time delay between variability of the quasar manifest in its various images. Light curves of the components of PG 1115+080 obtained in 2001–2006 at the Maidanak Observatory (Uzbekistan) are considered. A linear trend is observed in the light curves of all four components during 2006, with rapid brightness variations observed only in components A1 and C. This could be a consequence of microlensing or observational errors. Application of a modified cross-correlation method to the photometric data obtained in 2004–2005 yields the time delays τ BC = 22 −3 +2 days, τ AC = 12 −1 +2 days, and τ BA = 10 −3 +2 days, in agreement with results obtained earlier by Schechter et al. and Barkana for 1995–1996 light curves using two different statistical-analysis methods. However, the new values of τ BA and τ BC differ from those obtained by Vakulik et al. using the same Maidanak Observatory data. The ratio τ AC/τ BA ∼1.2, which is close to the values obtained by Barkana (∼1.13) and predicted by lens models (∼1.4); these differ from the values obtained by Schechter et al. (∼0.7) and Vakulik et al. (∼2.7).

Vibrational Activation of Methane Chemisorption: The Role of Symmetry.

Quantum state-resolved reactivity measurements probe the role of vibrational symmetry on the vibrational activation of the dissociative chemisorption of CH4 on Pt(111). IR-IR double resonance excitation in a molecular beam is used to prepare CH4 in all three different vibrational symmetry components A1, E, and F2 of the 2ν3 antisymmetric stretch overtone vibration. Methyl dissociation products chemisorbed on the cold Pt(111) surface are detected via reflection absorption infrared spectroscopy (RAIRS). We observe similar reactivity for CH4 prepared in the A1 and F2 sublevels but up to a factor of 2 lower reactivity for excitation of the E sublevel. It is suggested that differences in the localization of the C-H stretch amplitudes for the three states at the transition state leads to the observed difference in reactivity rather than state-specific vibrational energy transfer to electronic excitation of the metal.

Elucidating the process of activation of methyl-coenzyme M reductase.

Methyl-coenzyme M reductase (MCR) catalyzes the reversible reduction of methyl-coenzyme M (CH3-S-CoM) and coenzyme B (HS-CoB) to methane and heterodisulfide CoM-S-S-CoB (HDS). MCR contains the hydroporphinoid nickel complex coenzyme F430 in its active site, and the Ni center has to be in its Ni(I) valence state for the enzyme to be active. Until now, no in vitro method that fully converted the inactive MCRsilent-Ni(II) form to the active MCRred1-Ni(I) form has been described. With the potential use of recombinant MCR in the production of biofuels and the need to better understand this enzyme and its activation process, we studied its activation under nonturnover conditions and achieved full MCR activation in the presence of dithiothreitol and protein components A2, an ATP carrier, and A3a. It was found that the presence of HDS promotes the inactivation of MCRred1, which makes it essential that the activation process is isolated from the methane formation assay, which tends to result in minimal activation rates. Component A3a is a multienzyme complex that includes the mcrC gene product, an Fe-protein homolog, an iron-sulfur flavoprotein, and protein components involved in electron bifurcation. A hypothetical model for the cellular activation process of MCR is presented.

Elucidating the process of activation of methyl‐coenzyme M reductase (615.2)

Elucidating the process of activation of Methyl‐Coenzyme M Reductase from Methanobacter marbugensis Methyl‐coenzyme M reductase (MCR) catalyzes the reversible reduction of methyl‐coenzyme M (CH3‐S‐CoM) and coenzyme B (HS‐CoB) to methane and heterodisulfide CoM‐S‐S‐CoB. MCR contains the hydroporphinoid nickel complex coenzyme F430 in its active site and the Ni centre has to be in its Ni(I) valence state for the enzyme to be active. The mid‐point potential of the F430Ni (II)/Ni (I) is estimated to be ‐650mV. Since the electrons provided by H2 or CO are unlikely to reduce the Ni from Ni (II) to Ni (I), specialized system are needed to activate the MCR. The reduction of metal sites with low reduction potentials is possible by connecting an energetical uphill electron transfer with the hydrolysis of ATP. We confirm that for the activation of MCR only two enzymatic component are required, components A2 and A3a. It is reported here that COB inhibits the activation and HDS promotes the inactivation of MCRred1. Therefore, activation study was performed in non‐turn over condition in the presence of protein component A2 and A3a. Activation of MCR is shown with dithiothreitol as an electron source in the presence of MgATP, A2 and A3a protein complex. This is the first time the activation of MCR has been shown with an electron source that has a higher midpoint potential (‐330mV) than the Ni (I)/Ni (II) couple. Sequence analysis showed that A2 protein contains conserved nucleotide phosphate binding motif; walker A and B. Electron paramagnetic resonance studies of the A3a protein complex indicate that it contains more than one 4Fe‐4S clusters and Sequencing of A3a revealed the presence of Predicted Fe‐S flavoprotein, MCR‐C, Fe‐protein homologue, protein components involved in bifurcation and Cdh. Presence of both Mvh/Hdr/Fwd and Cdh complex indicate that H2 and Co‐dependent in vivo activation of MCR in M.marburgenesis share the common pathway to generate the low potential electron for reduction of Ni center in F430.

Raman spectroscopy study of lattice dynamics of macro-, micro-, and nanostructured barium titanates

The temperature dependences of the components A 1(2TO) and E(1TO) of the soft ferroelectric mode during phase transitions in single crystals, ceramics, polycrystalline and epitaxial thin films of barium titanate, as well as a superlattice consisting of alternating layers of barium and strontium titanates, have been studied using the Raman spectroscopy method. Abrupt changes in soft mode frequencies have been observed in the single crystal during phase transitions between tetragonal, orthorhombic, and rhombohedral phases. Smoothing of the temperature dependences of soft modes and the coexistence of phases have been observed in ceramics and polycrystalline films. In the epitaxial film, the sequence of structural transformations fundamentally differs from that observed in the single crystal; in the superlattice, the ferroelectric phase is stable to 550 K.

The binding mechanisms of F VIII Trp1707Ser mutation-associated inhibitor

To investigate the binding mechanisms of FVIII Trp1707Ser mutation-associated inhibitor. The APPT, PT, TT, Fg and FVIII:C were detected to make phenotypic diagnosis of haemophilia A. Inhibitors titer were measured by Bethesda method. Long distance-PCR (LD-PCR) and sequence-specific PCR were adopted for screening the intron 22 and intron 1 inversions respectively. FVIII coding and boundary sequences were analyzed by direct DNA sequencing. Inhibitor was reacted with different segments of FVIII, including heavy chain and its components A1 and A2, light chain and its components A3, C1 and C2. Corrected test was used to measure the remaining F VIII:C (% ) by adding pooled normal plasmas. After labeling purified inhibitors with biotin, western blot was performed to further confirm the binding reactions between inhibitors and segments. The haemophilia A patient had mild deficiency of FVIII:C (1.1%) and had high FVIII inhibitor titer of 18.4 BU. A mutation c.97223C>G in exon 14 of F8 gene resulted to p.Trp1707Ser was identified by DNA sequencing. Corrected test showed that the remaining F VIII:C was increased when inhibitors reacted with heavy chain and light chain, especially with heavy chain. The remaining FVIII:C was also increased in the A2 and C2 domain reactions. No significant differences were seen in the A1, A3 and C1 domain reactions. Antigen-antibody reaction bands were confirmed by western blots when degenerated B-domain deleted recombinant FVIII, A2 and C2 were used as antigens. The binding sites of FVIIITrp1707Ser mutation inhibitor were the A2 domain of heavy chain and C2 domain of light chain. The binding reaction with heavy chain was more intense.

Identities on Lie or Jordan-group-graded associative algebras

Let G be a finite group. Bahturin, Giambruno and Riley proved that if A is an (associatively) G-graded associative algebra such that the homogeneous component A1 satisfies a polynomial identity of degree d, then the entire algebra A satisfies a polynomial identity with degree bounded above by an explicit function of d and |G|. We extend this result to include associative algebras A that are either Lie or Jordan-G-graded. We deduce the following sharpening of a well-known theorem of Amitsur: if the invariant (respectively, skew-invariant) subspace of a Jordan (respectively, Lie) involution on A satisfies a polynomial identity of degree d, then the entire algebra A satisfies a polynomial identity of degree bounded above by an explicit function of d.

Antifungal activity of the primycin complex and its main components A1, A2 and C1 on a Candida albicans clinical isolate, and their effects on the dynamic plasma membrane changes

The in vitro antifungal activities of the macrolide lactone antibiotic complex primycin (PC) and its main components, A1 (50%), A2 (7.3%) and C1 (13%), against the opportunistic pathogenic fungus Candida albicans 33erg(+)were determined by microdilution testing. The MIC(100) (the minimal concentration required for 100% growth inhibition) values found, A2 (2 μg ml(-1)), PC (32 μg ml(-1)), A1 (32 μg ml(-1)) and C1 (64 μg ml(-1)), suggested that the biological activity of PC is highly dependent on the proportions of its constituents. In vivo measurements of the biophysical properties of plasma membranes were carried out by electron paramagnetic resonance (EPR) spectroscopic methods, using the spin probe 5-(4,4-dimethyloxazolidine-N-oxyl)stearic acid. Conventional EPR measurements demonstrated altered phase transition temperatures (Tm) of the plasma membrane of strain 33erg(+) as a consequence of treatment with PC or its constituents: for cells treated with 128 μg ml(-1) PC, A1, A2 or C1 for 15 min, Tm was 17, 21, 14.5 and 15 °C, respectively; that is significantly higher than the Tm of untreated cells, 12 °C. The molecular motions of the near-surface hydrophobic region of the plasma membrane, estimated by saturation transfer EPR spectroscopy, reflected changes in the membrane phases after the treatment. Two physiological membrane phases were detected in control samples: liquid-ordered and liquid-disordered, characterized by molecular movements ∼10(-6)-10(-8) s and ≥10(-9) s. The cells treated with the investigated compounds showed the strong presence of a non-physiological gel phase additional to the above phases, characterized by movements ≤10(-5) s.

On the impact of the Yarkovsky effect on Apophis’ orbit

In October 2009, a new set of optical observations of Apophis, a potentially hazardous asteroid, was published. These data have significantly expanded the interval of observations and their total number. In the article we compare the results of refinement of Apophis’ orbit made at the Jet Propulsion Laboratory (JPL, United States), the University of Pisa (Italy), and the Institute of Applied Astronomy (IAA) of the Russian Academy of Sciences with consideration for new observations. New orbits lead to a significant decrease in the probability of Apophis’ collision with the Earth in 2036. As a result of processing a large number of observations of asteroids approaching the Earth and main belt asteroids less than 40 km in size, with a large number of optical and, in many cases, radar observations in different oppositions, one of the authors revealed that additional acceleration affects their motion. This acceleration can be represented by the transversal component A2 in the orbital coordinate system. The presence of this acceleration can be interpreted as the Yarkovsky effect. The statistical properties of distribution of A2 for asteroids, for which it is determined quite reliably, evidence in favor of this interpretation. The value of additional acceleration for bodies the size of Apophis falls in the range ±10−13 AU/day2. In this paper we have calculated the probability of Apophis colliding with the Earth in 2036 at different values of the transversal component of additional acceleration A2. For the resulting points, a plot of the probability of the collision against the A2 value has been constructed. At A2 = −8.748 × 10−14 AU/day2 (and zero values of the radial A1 and normal A3 components) the nominal solution for Apophis’ orbit on April 13, 2029, is only 90 m from the middle of a “keyhole” 600 m in width, which leads to a collision of Apophis with the Earth in 2036. Since the scattering ellipse in the target plane in 2029 significantly overlaps the keyhole, the probability of collision at the given additional acceleration value is 0.0022. This result has been verified by the Monte Carlo method. Tests of 10000 random sets of orbital elements, which were found taking into account their correlation, have shown that 22 cases have resulted in virtual asteroids colliding with Earth in 2036. A plot of the probability of the collision against the value of A2 has been constructed.

Determination of Latent Transition Temperatures of Nonmesomorphs by Extrapolation Method in Binary Systems

Eight binary systems consisting of mesomorphs and nonmesomorphs (A1 or A2, + B1, B2, … B7, B8) were studied with a view to determine the latent transition temperature (LTT) for the nonmesomorphic component (B) of a binary system by an extrapolation method. Encouraging results supporting earlier views and LTT values were obtained for seven binary systems. Instead of reporting a single value of LTT, the range of temperature or two or three values are reported herewith depending upon the possible paths of extrapolation. LTT reported earlier for nonmesomorphs lie within the range of temperature determined presently. Though the “group slope value” differs from the earlier reported value, the group efficiency order remains the same. Thus, the present investigation raises the credibility of an extrapolation method to determine LTT and group efficiency order for nematic mesophase. Component A1 and A2 are nematogenic, namely, p-(p′-n-propyloxy benzoyloxy) anisole (A1) (90.0 to 116.0) and p-(p′-n-butyloxy benzoyloxy) anisole (A2) (116.0 to 105.5). B1 to B8 are Schiff's bases. Transition and melting temperatures are observed through hot stage polarizing microscope for binary mixtures and pure components.

The splitted beam profile of laser beam in the interaction of intense lasers with overdense plasmas

AbstractIn this paper, the interaction of intense lasers with overdense plasmas is investigated. Based on the modified nonlinear wave equation describing the interaction of intense laser and overdense plasmas in nonparaxial region, due to the influence of off-axis components a2 and a4 in nonparaxial region, we first find the three-splitted laser beam intensity profile, besides, discuss detailed the forming mathematic and some possible physical conditions of the single highly self-focusing beam profile, two-splitted beam, and three-splitted beam profile. In addition, we also investigate the influence of the parameters βE02 and ρ2 on splitted beam profiles.

Lie algebras and algebras of associative type

In the paper, some properties of algebras of associative type are studied, and these properties are then used to describe the structure of finite-dimensional semisimple modular Lie algebras. It is proved that the homogeneous radical of any finite-dimensional algebra of associative type coincides with the kernel of some form induced by the trace function with values in a polynomial ring. This fact is used to show that every finite-dimensional semisimple algebra of associative type A = ⊕αeG A α graded by some group G, over a field of characteristic zero, has a nonzero component A 1 (where 1 stands for the identity element of G), and A 1 is a semisimple associative algebra. Let B = ⊕αeG B α be a finite-dimensional semisimple Lie algebra over a prime field F p , and let B be graded by a commutative group G. If B = F p ⊗ ℤ A L , where A L is the commutator algebra of a ℤ-algebra A = ⊕αeG A α ; if ℚ ◯ ℤ A is an algebra of associative type, then the 1-component of the algebra K ◯ ℤ B, where K stands for the algebraic closure of the field F p , is the sum of some algebras of the form gl(n i ,K).

CONFIRMATION OF A RECENT BIPOLAR EJECTION IN THE VERY YOUNG HIERARCHICAL MULTIPLE SYSTEM IRAS 16293-2422

We present and analyze two new high-resolution (∼03), high-sensitivity (∼50 μJy beam−1) Very Large Array 3.6 cm observations of IRAS 16293–2422 obtained in 2007 August and 2008 December. The components A2α and A2β recently detected in this system are still present, and have moved roughly symmetrically away from source A2 at a projected velocity of 30–80 km s−1. This confirms that A2α and A2β were formed as a consequence of a very recent bipolar ejection from A2. Powerful bipolar ejections have long been known to occur in low-mass young stars, but this is—to our knowledge—the first time that such a dramatic one is observed from its very beginning. Under the reasonable assumption that the flux detected at radio wavelengths is optically thin free–free emission, one can estimate the mass of each ejecta to be of the order of 10−8 M☉. If the ejecta were created as a consequence of an episode of enhanced mass loss accompanied by an increase in accretion onto the protostar, then the total luminosity of IRAS 16293–2422 ought to have increased by 10%–60% over the course of at least several months. Between A2α and A2β, component A2 has reappeared, and the relative position angle between A2 and A1 is found to have increased significantly since 2003–2005. This strongly suggests that A1 is a protostar rather than a shock feature, and that the A1/A2 pair is a tight binary system. Including component B, IRAS 16293–2422 therefore appears to be a very young hierarchical multiple system.

(47171) 1999 TC 36, A transneptunian triple

We present new analysis of HST images of (47171) 1999 TC 36 that confirm it as a triple system. Fits to the point-spread function (PSF) consistently show that the apparent primary is itself composed of two similar-sized components. The two central components, A1 and A2, can be consistently identified in each of nine epochs spread over 7 years of time. In each instance, the component separation, ranging from 0.023 ± 0.002 to 0.031 ± 0.003 arcsec, is roughly one half of the Hubble Space Telescope’s diffraction limit at 606 nm. The orbit of the central pair has a semi-major axis of a ∼ 867 km with a period of P ∼ 1.9 days. These orbital parameters yield a system mass that is consistent with M sys = 12.75 ± 0.06 × 10 18 kg derived from the orbit of the more distant secondary, component B. The diameters of the three components are d A 1 = 286 - 38 + 45 km, d A 2 = 265 - 35 + 41 km and d B = 139 - 18 + 22 km . The relative sizes of these components are more similar than in any other known multiple in the Solar System. Taken together, the diameters and system mass yield a bulk density of ρ = 542 - 211 + 317 kg m - 3 . HST photometry shows that component B is variable with an amplitude of ⩾0.17 ± 0.05 magnitudes. Components A1 and A2 do not show variability larger than 0.08 ± 0.03 magnitudes approximately consistent with the orientation of the mutual orbit plane and tidally distorted equilibrium shapes. The system has high specific angular momentum of J/ J′ = 0.93, comparable to most of the known transneptunian binaries.