Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Auto-tuning of multivariable decoupling controllers

IFAC Symposia Series7115-120ISYS

Spectroscopic peculiarities in a 2D Coulomb potential under Aharonov-Bohm effect

In this paper we demonstrate some spectroscopic peculiarities which occur in the presence of the Aharonov-Bohm effect. As an object of investigation the system of a two-dimensional (2D) Coulomb potential in the presence of the Aharonov-Bohm flux is considered. It is shown, that the bound states in such a system “feel” the presence of the magnetic flux. In particular, the numerical analysis shows that the oscillator strengths of optical transitions turn into zero at some “special” values of the Aharonov-Bohm flux. As a result, some spectral lines (namely, the intensities of spectral lines) will disappear and this fact may be considered as an observable optical manifestation of the Aharonov-Bohm effect in the considered system. The dynamic polarisability of the bound states of an electron in such a system is also analyzed. It is shown numerically that the dynamic polarisability “strongly” depends on the values of the Aharonov-Bohm flux

Genetic compatibility among morphotypes of Vigna lanceolata and implications for breeding improved cultivars

As well as being part of the wider gene pool of cultivated species such as mungbean and cowpea, Vigna lanceolata Benth. is of agronomic interest as a potentially useful species in its own right. It is widely adapted across northern Australia from the coast to inland desert regions, and possesses attributes that make it potentially suited as a ley, cover crop or pasture legume in seasonally arid tropical environments. The species comprises several morphotypes that variously differ in their broad geographic distribution, life cycle, habit, edaphic adaptation and/or amphicarpy. In order to assess the potential for breeding improved cultivars, eight representative accessions were hybridised in a complete diallel cross and the viability and fertility of the resultant hybrid progeny evaluated. Of the 56 parental combinations in the diallel, 33 resulted in healthy F1 hybrid plants, and of these, nine were at least partly self-fertile. Six of these combinations were the reciprocal crosses between three of the perennial, tuberous-rooted, amphicarpic morphotypes. Another two were the reciprocal crosses between the two annual morphotypes. The patterns of relatedness among accessions indicated by the cross-pollination studies were broadly supported by DArT molecular marker analyses, and suggested that there has been some genetic differentiation within the V. lanceolata complex. Although the process of speciation remains far from complete, the levels of genetic compatibility between some morphotypes would be inadequate to enable a breeding program to draw easily on the full range of genetic diversity within V. lanceolata. Two plausible breeding options are suggested. The first is the development of perennial, tuberous-rooted, amphicarpic ideotypes suited perhaps as pasture or understorey legumes, drawing on selected accessions from the three perennial morphotypes, where there was sufficient genetic compatibility and which collectively have wide geographical spread. The second is an annual, freely seeding, fibrous-rooted, amphicarpic ideotype suited perhaps for use as a self-regenerating ley legume, drawing on selected accessions from the two annual morphotypes

Structural evolution of free-standing 2D silicon carbide upon heating

Two-dimensional Silicon Carbide (2D SiC) model is studied via molecular dynamics simulation to observe the structural evolution upon heating. A model contains 11040 atoms interacting via Vashishta potentials. The model is heated up from 50 K to 4500 K in order to observe the changes in structures during heating process. The melting point of free-standing 2D SiC is defined to be around 4050 K by temperature dependence of the heat capacity. The Lindemann criterion for 2D case is calculated and used to classify the behaviors of the liquid like and solid like atoms. The atomic mechanism of structural evolution upon heating is analyzed based on the occurrence/growth of liquid like atoms the average coordination number the ring statistics as well as the angular distributions

Expression and heritability of late flowering and other quantitative traits in cultivated × Australian wild mungbean hybrids

The expression and heritability of quantitative traits were examined in four hybrid mungbean populations, developed by crossing two cultivars, Kiloga and Berken, with two Australian wild accessions, ACC 1 and ACC 87. Phenological, morphological, agronomic and pod and seed traits were measured in the parental, F1, F2, and two F1 × parent backcross progeny generations. Plants were grown in large pots on benches, in autumn in the field at Townsville, Australia. The two cultivars were both early flowering (~5 weeks) and short duration, with short, thick stems, few branches, large leaflets, pods and seeds, and high harvest index. There were greater differences between the two wild accessions. ACC 1 was very late flowering (>12 weeks) even under the short days of autumn, and strongly indeterminate, with prostrate habit, prolific branching, thin stems, small leaflets and tiny seeds. The perennial type ACC 87 was intermediate in flowering (~6 weeks), with more robust, albeit still branched and twining growth habit, and larger leaflets, flowers, pods and seeds. Flowering in all crosses was conditioned by additive gene action with some dominance effects (with lateness recessive to earliness). The responses suggested that the extreme lateness of ACC 1 was due to the cumulative additive effects of multiple lateness genes. For most other traits, there were broad consistencies in trait expression in hybrid progeny and heritability between the different crosses, indicating general similarities in genetic control. Although broad-sense heritability for most traits was high, narrow-sense heritability was high to very high for twice as many traits in the ACC 87 as in the ACC 1 crosses, indicating higher levels dominance effects in the latter crosses. Several genetic and phenotypic correlations were identified between various traits, as well as associations between quantitative traits in this study and previously reported qualitative traits from the same populations. There were no gross genetic incompatibilities between the wild and cultivated accessions. However, irregularities in the segregation patterns in the progeny generations for seeds per pod suggested that there may have been cryptic hybrid breakdown effects at the gametic or zygotic level. The results of this study indicated that ACC 1 and ACC 87 are genetically distinctive, with the perennial form ACC 87 actually less distant from the domesticated mungbean than is ACC 1. The research provides yet further evidence that the Australian wild accessions add significant diversity to the mungbean primary germplasm

Use of DArT molecular markers for QTL analysis of drought-stress responses in soybean. I. Phenotypic evaluation of traits

Physiological drought stress responses were assessed in recombinant inbred lines (RILs) from three soybean (Glycine max (L.) Merr.) crosses, in preparation for quantitative trait locus (QTL) analyses using Diversity Arrays Technology (DArT) markers. The three RIL populations were derived from pairwise crosses between three genotypes, cv. Valder, CPI 26671 and G2120, which in previous studies had differed in drought-stress response. Of particular interest was the landrace variety G2120, which in the previous reports had recovered better after severe drought. To assess drought stress response, the plants were grown in deep cylindrical pots in the glasshouse and exposed to severe water deficit followed by re-watering. Two plants to be genotyped were grown in each pot, together with one plant of G2120, which served as a reference plant against which the responses of the two other plants were assessed. Traits recorded included measures of relative water content (RWC), epidermal conductance (ge) and recovery in growth following re-watering. The responses in the reference and parental plants and the RIL populations were broadly consistent with previous studies. As plant-available water in the soil declined, both RWC and ge declined, although the relation between RWC and ge was exponential, rather than linear as in previous studies. Analysis of variance revealed large environmental effects on most of the traits, which resulted in high coefficients of variation and low estimates of broad-sense heritability. However, there were significant differences at both the population and genotype levels for all key traits, confirming the presence of genetic variation for drought-stress response. Some opportunities for enhancing the observed genetic differences and reducing the environmental noise in future studies are canvassed. Application of the observed phenotypic data reported in this paper in subsequent QTL analyses based on DArT markers is reported in the companion paper

Use of DArT molecular markers for QTL analysis of drought-stress responses in soybean. II. Marker identification and QTL analyses

This study applied newly developed Diversity Arrays Technology (DArT) and soybean and mungbean DArT libraries for quantitative trait locus (QTL) linkage analysis in recombinant inbred lines (RILs) from three soybean crosses that had previously been assessed for physiological response to severe drought stress. The phenotypic assessments had identified statistically significant genetic variation among and within the RIL populations and their parents for three drought-related responses: epidermal conductance (ge) and relative water content (RWC) during stress, and plant recovery after stress. The new linkage maps containing only DArT markers for the three populations individually contained 196–409 markers and 15–22 linkage groups (LGs), with an aggregate length ranging from 409.4 to 516.7 cM. An integrated map constructed by using the marker data from all three RIL populations comprised 759 DArT markers, 27 LGs and an expanded length of 762.2 cM. Two populations with the landrace accession G2120 as a parent, CPI 26671 × G2120 (CG) and Valder × G2120 (VG), respectively contained 106 and 34 QTLs. In each of these populations, 10 LGs harboured QTLs associated with RWC, ge and recovery ability, of which six similar LGs were associated with drought tolerance. A BLAST (Basic Local Alignment Search Tool) search for sequences of 19 selected DArT markers linked to QTLs conditioning the drought-response traits indicated that 18 DArT markers were unique and aligned to 12 soybean chromosomes. Comparison of these sequenced DArT markers with other markers associated with drought-related QTLs in previously reported studies using other marker types confirmed that five of them overlapped, whereas the remaining 13 were new. Except for chromosome 15, the chromosomes with which the DArT QTLs in the CG and VG populations were associated were those that had been shown to harbour drought-related QTLs in previous studies. A BLASTx protein database search identified soPt-856602 as being associated with the gene for a probable glycosyltransferase At5g03795-like isoform X1 on chromosome 6. Although the several QTLs identified in the study were all of relatively minor effect, it was concluded that, because the DArT technology involves large numbers of markers and enables many lines to be genotyped simultaneously, it should help the process of manipulating multiple QTLs and so enhance their likely cumulative effect

An Experimental Study of Muscle Coordination and Function during Human Locomotion

How humans solve the ill-posed problem of motor control is still a mystery. In this paper, we attempt to decompose human walking and running as the main movements of a leg into units of motor function. We introduce the key concept of “A-A ratio,” defined as the ratio of an extensor muscle’s electromyography (EMG) signal to the sum of agonist and antagonist muscles’ EMG signals. Human walking and running are then decomposed into two units of motor function by applying Principal Component Analysis (PCA) to the A-A ratio dataset. The kinematic meanings of these units are also experimentally shown by using a human-like musculoskeletal leg robot

Crohn’s Disease-Associated Adherent-Invasive Escherichia coli Manipulate Host Autophagy by Impairing SUMOylation

The intestinal mucosa of Crohn’s disease (CD) patients is abnormally colonized with adherent-invasive Escherichia coli (AIEC) that are able to adhere to and to invade intestinal epithelial cells (IECs), to survive in macrophages, and to induce a pro-inflammatory response. AIEC persist in the intestine, and induce inflammation in CEABAC10 transgenic mice expressing human CAECAM6, the receptor for AIEC. SUMOylation is a eukaryotic-reversible post-translational modification, in which SUMO, an ubiquitin-like polypeptide, is covalently linked to target proteins. Here, we investigated the role of SUMOylation in host responses to AIEC infection. We found that infection with the AIEC LF82 reference strain markedly decreased the levels of SUMO-conjugated proteins in human intestinal epithelial T84 cells. This was also observed in IECs from LF82-infected CEABAC10 transgenic mice. LF82-induced deSUMOylation in IECs was due in part to increased level of microRNA (miR)-18, which targets PIAS3 mRNA encoding a protein involved in SUMOylation. Over-expression of SUMOs in T84 cells induced autophagy, leading to a significant decrease in the number of intracellular LF82. Consistently, a decreased expression of UBC9, a protein necessary for SUMOylation, was accompanied with a decrease of LF82-induced autophagy, increasing bacterial intracellular proliferation and inflammation. Finally, the inhibition of miR-18 significantly decreased the number of intracellular LF82. In conclusion, our results suggest that AIEC inhibits the autophagy response to replicate intracellularly by manipulating host SUMOylation