2,593 research outputs found
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The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution
Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. Results: BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. Conclusions: The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type
Deep Chandra Observations of A2495: A Possible Sloshing-regulated Feedback Cycle in a Triple-offset Galaxy Cluster
We present the analysis of new, deep Chandra observations (130 ks) of the galaxy cluster A2495. This object is known for the presence of a triple offset between the peaks of the intracluster medium (ICM), the brightest cluster galaxy (BCG), and the warm gas glowing in Hα line. The new Chandra data confirm that the X-ray emission peak is located at a distance of âŒ6.2 kpc from the BCG, and at âŒ3.9 kpc from the Hα emission peak. Moreover, we identify two generations of X-ray cavities in the ICM, likely inflated by the central radio galaxy activity. Through a detailed morphological and spectral analysis, we determine that the power of the active galactic nucleus (AGN) outbursts (P cav = 4.7 ± 1.3 Ă 1043 erg sâ1) is enough to counterbalance the radiative losses from ICM cooling (L cool = 5.7 ± 0.1 Ă 1043 erg sâ1). This indicates that, despite a fragmented cooling core, A2495 still harbors an effective feedback cycle. We argue that the offsets are most likely caused by sloshing of the ICM, supported by the presence of spiral structures and a probable cold front in the gas at âŒ58 kpc east of the center. Ultimately, we find that the outburst interval between the two generations of X-ray cavities is of the order of the dynamical sloshing timescale, as already hinted from the previous Chandra snapshot. We thus speculate that sloshing may be able to regulate the timescales of AGN feedback in A2495, by periodically fueling the central AGN
Generalized Hermite-Gauss decomposition of the two-photon state produced by spontaneous parametric down-conversion
We provide a general decomposition of the two-photon state produced by
spontaneous parametric down-conversion in Hermite-Gaussian modes, in the case
that the pump beam is described by a Hermite-Gaussian beam of any order. We
show that the spatial correlations depend explicitly on the order of the pump
beam, as well as other experimental parameters. We use the decomposition to
demonstrate a few interesting cases. Our results are applicable to the
engineering of two-photon spatial entanglement, in particular for non-Gaussian
states.Comment: 14 page draft, 5 figure
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Unexpected vertical structure of the Saharan Air Layer and giant dust particles during AER-D
The Saharan Air Layer (SAL) in the summertime eastern Atlantic is typically well mixed and 3-4âkm deep, overlying the marine boundary layer (MBL). In this paper, we show experimental evidence that at times a very different structure can be observed. During the AERosol properties - Dust (AER-D) airborne campaign in August 2015, the typical structure described above was observed most of the time, and was associated with a moderate dust content yielding an aerosol optical depth (AOD) of 0.3-0.4 at 355ânm. In an intense event, however, an unprecedented vertical structure was observed close to the eastern boundary of the basin, displaying an uneven vertical distribution and a very large AOD (1.5-2), with most of the dust in a much lower level than usual (0.3-2âkm). Estimated dust concentrations and column loadings for all flights during the campaign spanned 300-5500 and 0.8-7.5âgâmâ2, respectively. The shortwave direct radiative impact of the intense dust event has been evaluated to be as large as â260±30 and â120±15âWâmâ2 at the surface and top of atmosphere (TOA), respectively. We also report the correlation of this event with anomalous lightning activity in the Canary Islands. In all cases, our measurements detected a broad distribution of aerosol sizes, ranging from âŒ0.1 to âŒ80â”m (diameter), thus highlighting the presence of giant particles. Giant dust particles were also found in the MBL. We note that most aerosol models may miss the giant particles due to the fact that they use size bins up to 10-25â”m. The unusual vertical structure and the giant particles may have implications for dust transport over the Atlantic during intense events and may affect the estimate of dust deposited to the ocean. We believe that future campaigns could focus more on events with high aerosol load and that instrumentation capable of detecting giant particles will be key to dust observations in this part of the world
A BCG with Offset Cooling:Is the AGN Feedback Cycle Broken in A2495?
We present a combined radio/X-ray analysis of the poorly studied galaxy cluster A2495 (z = 0.07923) based on new EVLA and Chandra data. We also analyze and discuss Hα emission and optical continuum data retrieved from the literature. We find an offset of âŒ6 kpc between the cluster brightest cluster galaxy (BCG) (MCG+02-58-021) and the peak of the X-ray emission, suggesting that the cooling process is not taking place on the central galaxy nucleus. We propose that sloshing of the intracluster medium (ICM) could be responsible for this separation. Furthermore, we detect a second, âŒ4 kpc offset between the peak of the Hα emission and that of the X-ray emission. Optical images highlight the presence of a dust filament extending up to âŒ6 kpc in the cluster BCG and allow us to estimate a dust mass within the central 7 kpc of 1.7 Ă 105 M . Exploiting the dust-to-gas ratio and the L Hα-M mol relation, we argue that a significant amount (up to 109 M ) of molecular gas should be present in the BCG of this cluster. We also investigate the presence of ICM depressions, finding two putative systems of cavities; the inner pair is characterized by t age ⌠18 Myr and P cav ⌠1.2 Ă 1043 erg s-1, the outer one by t age ⌠53 Myr and P cav ⌠5.6 Ă 1042 erg s-1. Their age difference appears to be consistent with the freefall time of the central cooling gas and with the offset timescale estimated with the Hα kinematic data, suggesting that sloshing is likely playing a key role in this environment. Furthermore, the cavities' power analysis shows that the active galactic nucleus energy injection is able to sustain the feedback cycle, despite cooling being offset from the BCG nucleus.</p
Economic assessment of Holstein-Friesian dairy cows of divergent Economic Breeding Index evaluated under seasonal calving pasture-based management
peer-reviewedThe objective of this study was to investigate the economic performance of 2 genetic groups (GG) of Holstein-Friesian dairy cows of divergent Economic Breeding Index (EBI), evaluated within 3 contrasting spring-calving pasture-based feeding treatments (FT). The study was a simulated economic appraisal, using the Moorepark Dairy Systems Model, a stochastic budgetary simulation model integrating biological data obtained from a 4-yr experiment conducted from 2013 to 2016. The 2 divergent GG were (1) high EBI representative of the top 5% nationally (elite) and (2) EBI representative of the national average (NA). The 3 FT were reflective of slight restriction to generous feeding. The elite GG had the lowest replacement rate, and therefore had lower replacement costs and an older and more productive parity structure. The elite GG consistently had higher sales of milk (on average +3% or +18,370 kg of milk) and milk solids (milk fat plus protein yield; +8.7% or +4,520 kg) compared with the NA GG across the 3 FT scenarios. Milk income was consequently greater for elite versus NA (on average +9.5% or +âŹ21,489) cows. Livestock sales were greater (on average +13.2% or +âŹ4,715) for NA compared with elite cows. Baseline net farm profit and net profit/ha at a base milk price of 29.5 cents per liter (3.3% protein and 3.6% fat) were on average âŹ31,156, and âŹ772 greater for elite compared with NA cows across the 3 FT. Greater profitability achieved with elite cows in each of the FT investigated demonstrated the adaptability of high-EBI cows across different levels of feeding intensities in seasonal pasture-based feeding systems. Sensitivity analysis of varying milk price and concentrate cost did not result in a reranking of GG for farm profit. This study clearly demonstrates the power of a suitably constructed genetic-selection index together with a well-considered breeding program to deliver genetics capable of favorable change to farm physical performance and profit over a relatively short duration
Beam Mode Expansion of Corrugated Conical Horns with Phase Correcting Lens: Application to Radioastronomy Receivers
A classical radioastronomy receiver is fed with a corrugated horn and an independent lens,
both placed in a cryostat to lower the noise temperature. The beam is focused and directed using a
combination of elliptical and plane mirrors. This paper proposes modifying the initial feeding system
by placing the lens onto the horn aperture, thereby allowing a size reduction of the horn and lens, and a
simplification of their mechanical design. The profiled lens is shaped to correct the phase error on the
horn aperture. A quasi-optical model of the horn-plus-lens system has been developed using a Beam
Mode Expansion (BME). Results using both a hyperbolic-planar lens and a spherical-elliptical lens,
as well as results obtained by using Geometrical Optics (GO) with a KirchoffâHuygens integration
to get the far-field pattern, have been compared with measurements. As a direct application, a full
focusing system for the new 40-m radiotelescope at the âCentro AstronÂŽomico de Yebesâ is presented
for the 22, 30 and 45 GHz bands. This paper has developed a QO model for a corrugated conical horn
with a phase-correcting lens
Chandra and XMM-Newton observations of the merging cluster of galaxies PLCK G036.7+14.9
We present Chandra and XMM-Newton observations of PLCK G036.7+14.9 from the
Chandra-Planck Legacy Program. The high resolution X-ray observations reveal
two close subclusters, G036N and G036S, which were not resolved by previous
ROSAT, optical, or recent Planck observations. We perform detailed imaging and
spectral analyses and use a simplified model to study the kinematics of this
system. The basic picture is that PLCK G036.7+14.9 is undergoing a major merger
(mass ratio close to unity) between the two massive subclusters, with the
merger largely along the line-of-sight and probably at an early stage. G036N
hosts a small, moderate cool-core, while G036S has at most a very weak
cool-core in the central 40 kpc region. The difference in core cooling times is
unlikely to be caused by the ongoing merger disrupting a pre-existing cool-core
in G036S. G036N also hosts an unresolved radio source in the center, which may
be heating the gas if the radio source is extended. The Planck derived mass is
higher than the X-ray measured mass of either subcluster, but is lower than the
X-ray measured mass of the whole cluster, due to the fact that Planck does not
resolve PLCK G036.7+14.9 into subclusters and interprets it as a single
cluster. This mass discrepancy could induce significant bias to the mass
function if such previously unresolved systems are common in the Planck cluster
sample. High resolution X-ray observations are necessary to identify the
fraction of such systems and correct such a bias for the purpose of precision
cosmological studies.Comment: 23 pages, 8 figures (low resolution) with additional 12 figures in
the Appendix, accepted for publication in Ap
Beam Mode Expansion of Corrugated Conical Horns with Phase Correcting Lens: Application to Radioastronomy Receivers
A classical radioastronomy receiver is fed with a corrugated horn and an independent lens,
both placed in a cryostat to lower the noise temperature. The beam is focused and directed using a
combination of elliptical and plane mirrors. This paper proposes modifying the initial feeding system
by placing the lens onto the horn aperture, thereby allowing a size reduction of the horn and lens, and a
simplification of their mechanical design. The profiled lens is shaped to correct the phase error on the
horn aperture. A quasi-optical model of the horn-plus-lens system has been developed using a Beam
Mode Expansion (BME). Results using both a hyperbolic-planar lens and a spherical-elliptical lens,
as well as results obtained by using Geometrical Optics (GO) with a KirchoffâHuygens integration
to get the far-field pattern, have been compared with measurements. As a direct application, a full
focusing system for the new 40-m radiotelescope at the âCentro AstronÂŽomico de Yebesâ is presented
for the 22, 30 and 45 GHz bands. This paper has developed a QO model for a corrugated conical horn
with a phase-correcting lens
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