This article describes the first results obtained from the Surface Waves Investigation and Monitoring (SWIM) instrument carried by the China France Oceanography Satellite (CFOSAT), which was launched ...on October 29, 2018. SWIM is a Ku-band radar with a near-nadir scanning beam geometry. It was designed to measure the spectral properties of surface ocean waves. First, the good behavior of the instrument is illustrated. It is then shown that the nadir products (significant wave height, normalized radar cross section, and wind speed) exhibit an accuracy similar to standard altimeter missions, thanks to a new retracking algorithm, which compensates a lower sampling rate compared to standard altimetry missions. The off-nadir beam observations are analyzed in detail. The normalized radar cross section varies with incidence and wind speed as expected from previous studies presented in the literature. We illustrate that, in order to retrieve the wave spectra from the radar backscattering fluctuations, it is crucial to apply a speckle correction derived from the observations. Directional spectra of ocean waves and their mean parameters are then compared to wave model data at the global scale and to in situ data from a selection of case studies. The good efficiency of SWIM to provide the spectral properties of ocean waves in the wavelength range 70-500 m is illustrated. The main limitations are discussed, and the perspectives to improve the data quality are presented.
We study the dependence of the galaxy size evolution on morphology, stellar mass and large-scale environment for a sample of 298 group and 384 field quiescent early-type galaxies from the COSMOS ...survey, selected from z ∼ 1 to the present, and with masses log(M/M) > 10.5.
From a detailed morphological analysis we infer that ∼80 per cent of passive galaxies with mass log(M/M) > 10.5 have an early-type morphology and that this fraction does not evolve over the last 6 Gyr. However, the relative abundance of lenticular and elliptical galaxies depends on stellar mass. Elliptical galaxies dominate only at the very high mass end - log(M/M) > 11 - while S0 galaxies dominate at lower stellar masses - 10.5 < log(M/M) < 11.
The galaxy size growth depends on galaxy mass range and early-type galaxy morphology, e.g. elliptical galaxies evolve differently than lenticular galaxies. At the low-mass end - 10.5 < log(M/M) < 11 - ellipticals do not show strong size growth from z ∼ 1 to the present (10 to 30 per cent depending on the morphological classification). On the other end, massive ellipticals - log(M/M) > 11.2 - approximately doubled their size. Interestingly, lenticular galaxies display different behaviour: they appear more compact on average and they do show a size growth of ∼60 per cent since z = 1 independent of stellar mass range.
We compare our results with state-of-the art semi-analytic models. While major and minor mergers can account for most of the galaxy size growth, we find that with present data and the theoretical uncertainties in the modelling we cannot state clear evidence favouring either merger or mass-loss via quasar and/or stellar winds as the primary mechanism driving the evolution.
The galaxy mass-size relation and size growth do not depend on environment in the halo mass range explored in this work (field to group mass log(M
h/M) < 14), i.e. group and field galaxies follow the same trends. At low redshift, where we examine both Sloan Digital Sky Survey and COSMOS groups, this result is at variance with predictions from some current hierarchical models that show a clear dependence of size growth on halo mass for massive ellipticals (log(M
*/M) > 11.2). In future work, we will analyse in detail if this result is specific of the observations and model used in this work.
Brightest Cluster Galaxies (BCG) and satellite galaxies lie on the same mass-size relation, at variance with predictions from hierarchical models, which predict that BCGs should have larger sizes than satellites because they experience more mergers in groups over the halo mass range probed.
We analyse the mass–size relation of ∼400 quiescent massive ETGs (M
*/M⊙ > 3 × 1010) hosted by massive clusters (M200 ∼ 2–7 × 1014M⊙) at 0.8 < z < 1.5, compared to those found in the field at the ...same epoch. Size is parametrized using the mass-normalized B-band rest-frame size,
$\gamma =R_{\rm e}/M_{11}^{0.57}$
. We find that the γ distributions in both environments peak at the same position, but the distributions in clusters are more skewed towards larger sizes. This tail induces average sizes ∼30–40 per cent larger for cluster galaxies than for field galaxies of similar stellar mass, while the median sizes are statistically the same with a difference of ∼10 ± 10 per cent. Since this size difference is not observed in the local Universe, the evolution of average galaxy size at fixed stellar mass from z ∼ 1.5 for cluster galaxies is less steep at more than 3σ (∝(1 + z)−0.53 ± 0.04) than the evolution of field galaxies (∝(1 + z)−0.92 ± 0.04). The difference in evolution is not measured when the median values of γ are considered: ∝(1 + z)−0.84 ± 0.04 in the field versus ∝(1 + z)−0.71 ± 0.05 in clusters. In our sample, the tail of large galaxies is dominated by galaxies with 3 × 1010 < M
*/M⊙ < 1011. At this low-mass end, the difference in the average size is better explained by the accretion of new galaxies that are quenched more efficiently in clusters and/or by different morphological mixing in the cluster and field environments. If part of the size evolution would be due to mergers, the difference that we see between cluster and field galaxies could be caused by higher merger rates in clusters at higher redshift, when galaxy velocities are lower.
Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) have increased their stellar mass by a factor of almost 2 between z ∼ 0.9 and ...z ∼ 0.2. The numerical simulations further suggest that more than half this mass is accreted through major mergers. Using a sample of 18 distant galaxy clusters with over 600 spectroscopically confirmed cluster members between them, we search for observational evidence that major mergers do play a significant role. We find a major merger rate of 0.38 ± 0.14 mergers per Gyr at z ∼ 1. While the uncertainties, which stem from the small size of our sample, are relatively large, our rate is consistent with the results that are derived from numerical simulations. If we assume that this rate continues to the present day and that half of the mass of the companion is accreted on to the BCG during these mergers, then we find that this rate can explain the growth in the stellar mass of the BCGs that is observed and predicted by simulations. Major mergers therefore appear to be playing an important role, perhaps even the dominant one, in the build up of stellar mass in these extraordinary galaxies.
The growing range of drug resistant parasitic nematode populations threatens the sustainability of ruminant farming worldwide. In this context, nutraceuticals, animal feed that provides necessary ...dietary requirements while ensuring parasite control, could contribute to increase farming sustainability in developed and low resource settings. In this study, we evaluated the anthelmintic potential of lupin seed extracts against the major ruminant trichostrongylids, Haemonchus contortus and Teladorsagia circumcincta. In vitro observations showed that seed extracts from commercially available lupin varieties could significantly but moderately inhibit larval migration. This anthelmintic effect was mediated by the seed alkaloid content and was potent against both fully susceptible and multidrug resistant H. contortus isolates as well as a susceptible T. circumcincta isolate. Analytical chemistry revealed a set of four lupanine and sparteine-derivatives with anthelmintic activity, and electrophysiology assays on recombinant nematode acetylcholine receptors suggested an antagonistic mode of action for lupin alkaloids. An in vivo trial in H. contortus infected lupin-fed ewes and goats failed to demonstrate any direct anthelmintic effect of crude lupin seeds but infected lupin-fed goats suffered significantly less parasite-mediated blood losses. Altogether, our findings suggest that the anthelmintic potential of lupin remains limited. However, the potent alkaloids identified could lead to the development of novel drugs or may be used in combination with current anthelmintics to improve their efficacy.
We isolated and compared three tomato spotted wilt virus (TSWV) isolates from lettuce (TSWV-Let), pepper (TSWV-Pep), and tomato (TSWV-Tom) from central Mexico to determine their ability to infect a ...set of eighteen differential plant species from seven families. TWSV-Let was an aggressive isolate with the ability to infect up to 52% of the differential plants, including maize, under greenhouse conditions. The nucleotide (nt) sequences of the three isolates are more than 90% similar in the M and S RNA segments. In the M segment of the TSWV-Let isolate, we detected nt changes in their intergenic region (IGR) and, in the Gc gene, a region containing a recombination site, as well as a synapomorphy associated with one of three sites under positive selection with a change in one aa residue (a cysteine-to-valine mutation). We speculate on the association of these features in the Gc gene with host selection, adaptation, aggressiveness, and ability to infect maize plants.
We present the results of a detailed analysis of galaxy properties along the red sequence in XMMU J1229+0151, an X-ray selected cluster at z = 0.98 drawn from the High Acuity Wide field K-band Imager ...Cluster Survey. Taking advantage of the broad photometric coverage and the availability of 77 spectra in the cluster field, we fit synthetic spectral energy distributions, and estimate stellar masses and photometric redshifts, which we use to determine the cluster membership. We investigate morphological and structural properties of red sequence galaxies and find that elliptical galaxies populate the bright end, while S0 galaxies represent the predominant population at intermediate luminosities, with their fraction decreasing at fainter magnitudes. A comparison with the low-redshift sample of the Wide Field Nearby Galaxy-clusters Survey cluster survey reveals that at z ∼ 1 the bright end of the red sequence of XMMU J1229+0151 is richer in S0 galaxies. The faint end of the red sequence in XMMU J1229+0151 appears rich in disc-dominated galaxies, which are rarer in the low-redshift comparison sample at the same luminosities. Despite these differences between the morphological composition of the red sequence in XMMU J1229+0151 and in low-redshift samples, we find that to within the uncertainties, no such difference exists in the ratio of luminous to faint galaxies along the red sequence.
Endophytes infect living plant tissues without causing symptoms of disease. Indeed, many of them contribute to the resistance phenotype of their host. However, fungal endophytes are generally closely ...related to plant pathogens, fungi that either develop within living host tissue (biotrophic fungi) or that kill the host cells and then live in the dead tissue (necrotrophic fungi). We adopted a phylogenetic approach to investigate whether these strategies represent evolutionarily stable lifestyles and to elucidate their general phylogenetic relationships. We analysed 163 fungal strains for which we found information on the sequence of the 5.8S rRNA gene and the flanking internal transcribed spacer regions, the identity of the host plant and the concrete phenotypic outcome of the infection. A Maximum-Likelihood analysis combined with ancestral character mapping by maximum parsimony revealed that some fungal lineages had switched multiple times between a necrotrophic and an endophytic lifestyle. Ancestral character mapping indicated a minimum of four changes from an endophytic to a necrotrophic lifestyle, four changes in the opposite direction and eight changes among these lifestyles for which the direction could not be determined unambiguously. By contrast, biotrophs formed five clusters that did not contain necrotrophs or endophytes. Once biotrophy evolves there is apparently no regression to one of the other two lifestyles. We conclude that biotrophy usually represents a derived and evolutionarily stable trait, whereas fungi easily can switch between an endophytic and necrotrophic lifestyle at the evolutionary and even the ecological timescale. Future experimental studies should focus on the environmental or genetic changes that cause the rapid switches between these two phenotypically different lifestyles.
The thermal conductivity of diameter modulated SiC nanowires is computed with the non-equilibrium Molecular Dynamics (NEMD) method. The two main polytypes 3C (zinc-blend) and 2H (wurtzite) of SiC ...nanowires are investigated, but also the superlattice SiC nanowires with shape modulation. For the case of the shape modulated nanowires the Kapitza resistance is calculated with both NEMD and Equilibrium MD (EMD) methods. This thermal resistance is related with the restrictions between two different cross sections. Finally, we proceed to the physical explanation of this phenomenon with the help of the partial densities of states of phonons.
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