Aims
The aim of this study was to find and use rhizobacteria able to confer plants advantages to deal with saline conditions.
Methods and Results
We isolated 24 different bacterial species from the ...rhizosphere of halophyte plants growing in Santiago del Estero, Argentina salt flat. Four strains were selected upon their ability to grow in salinity and their biochemical traits associated with plant growth promotion. Next, we tested the adhesion on soybean seeds surface and root colonization with the four selected isolates. Isolate 19 stood out from the rest and was selected for further experiments. This strain showed positive chemotaxis towards soybean root exudates and a remarkable ability to form biofilm both in vitro conditions and on soybean roots. Interestingly, this trait was enhanced in high saline conditions, indicating the extremely adapted nature of the bacterium to high salinity. In addition, this strain positively impacted on seed germination, plant growth and general plant health status also under saline stress.
Conclusions
A bacterium isolate with outstanding ability to promote seed germination and plant growth under saline conditions was found.
Significance and Impact of the Study
The experimental approach allowed us to find a suitable bacterial candidate for a biofertilizer intended to alleviate saline stress on crops. This would allow the use of soil now considered inadequate for agriculture and thus prevent further advancement of agriculture frontiers into areas of environmental value.
Abstract Irregular cleavage divisions are expected to produce chromosomally deviant embryos. We investigated whether embryos from irregular cleavages could develop into euploid blastocysts, and, if ...so, whether any evidence existed of a self-correction mechanism of the embryo. We also investigated the role of different dynamic aspects of morula compaction in this process. A total of 791 embryos from 141 patients undergoing pre-implantation genetic screening were retrospectively analysed using a time-lapse imaging system, and multiple cell divisions were evaluated. A total of 276 embryos developed into blastocysts suitable for biopsy and chromosome screening through array-comparative genomic hybridization. As well as testing trophectoderm biopsy specimens for aneuploidy, excluded cells of 18 blastocysts, which developed from partially compacted morulas, were also analysed. Unique data on the developmental fate of embryos with cleavage abnormalities are presented, and a potential mechanism of ‘aneuploidy rescue’ is postulated through which mosaic embryos may form partially compacted morulas to exclude aneuploid cells. In addition, this process seems to be less efficient in older women. The data obtained also provide further evidence that excluded cells should not be used to infer the cytogenetic status of the embryo.
Context. The source 4U 1702-429 (Ara X-1) is a low-mass X-ray binary system hosting a neutron star. Albeit the source is quite bright (~1037 erg s-1) its broadband spectrum has never been studied. ...Neither dips nor eclipses have been observed in the light curve suggesting that its inclination angle is smaller than 60°. Aims. We analysed the broadband spectrum of 4U 1702-429 in the 0.3–60 keV energy range, using XMM-Newton and INTEGRAL data, to constrain its Compton reflection component if it is present. Methods. After excluding the three time intervals in which three type-I X-ray bursts occurred, we fitted the joint XMM-Newton and INTEGRAL spectra obtained from simultaneous observations. Results. A broad emission line at 6.7 keV and two absorption edges at 0.87 and 8.82 keV were detected. We found that a self-consistent reflection model fits the 0.3–60 keV spectrum well. The broadband continuum is composed of an emission component originating from the inner region of the accretion disc, a Comptonised direct emission coming from a corona with an electron temperature of 2.63 ± 0.06 keV and an optical depth τ = 13.6 ± 0.2, and, finally, a reflection component. The best-fit indicates that the broad emission line and the absorption edge at 8.82 keV, both associated with the presence of Fe xxv ions, are produced by reflection in the region above the disc with a ionisation parameter of Log(ξ) ≃ 2.7. We have inferred that the inner radius, where the broad emission line originates, is 64+52-15 km, and the inner radius of the accretion disc is 39+6-8 km. The emissivity of the reflection component and the inclination angle of the system are r-3.2+0.5-5.1and 44+33-6degrees, respectively. The absorption edge at 0.87 keV is associated to the presence of O viii ions and it is produced in a region above the disc with Log(ξ) ≃ 1.9.
ABSTRACT
1RXS J180408.9–342058 is a low-mass X-ray binary hosting a neutron star, which shows X-ray activity at very different mass-accretion regimes, from very faint to almost the Eddington ...luminosity. In this work, we present a comprehensive X-ray study of this source using data from the Neil Gehrels Swift Observatory, NuSTAR, and INTEGRAL/JEM-X. In order to follow the spectral evolution, we analysed the 2015 outburst using Swift data and three NuSTAR observations. Besides the canonical hard and soft spectral states, we identified the rarely observed intermediate state. This was witnessed by the appearance of the accretion disc emission in the spectrum (at kTdisc ∼0.7 keV) and the simultaneous cooling of the hot corona. In addition, we also unveiled a hard tail above 30 keV in this state. In the hard state, a thermal Comptonization model with two seed photons populations (kTs,1 ∼ 1.5 keV and kTs,2 ∼ 0.4 keV, respectively) and a hot Comptonizing plasma, represents the physically best motivated scenario to describe the data. We also estimated a reflection fraction below 20 per cent in all states, while no constraints on the inclination and only lower limits on the inner disc radius could be inferred. Finally, we studied a number of type-I X-ray bursts displayed from the source, one of them at the Eddington limit (observed with JEM-X). Their characteristics, combined with the clocked behaviour observed during the intermediate state, point out H/He composition for the accreted material, which makes unlikely the helium dwarf nature for the companion.
ABSTRACT
We present a multiband search for X-ray, optical, and γ-ray emission of the radio binary millisecond pulsar J1836-2354A, hosted in the globular cluster M22. X-ray emission is significantly ...detected in two Chandra observations, performed in 2005 and 2014, at a luminosity of ∼2–3 × 1030 erg s−1, in the 0.5–8 keV energy range. The radio and the X-ray source positions are found consistent within 1σ error box. No detection is found in archival XMM–Newton and Swift/XRT observations, compatible with the Chandra flux level. The low statistics prevents us to assess if the X-ray source varied between the two observations. The X-ray spectrum is consistent with a power-law of photon index ∼1.5. We favour as the most probable origin of the X-ray emission an intrabinary shock scenario. We searched for optical and γ-ray counterparts to the radio source using data from Hubble Space Telescope and Fermi–LAT catalogues, respectively. No optical counterpart down to V = 25.9 and I = 24.7 (3σ) is detected, which suggests a companion mass of 0.1–0.2 M⊙. Combined with the low X-ray luminosity, this is consistent with a black widow nature of PSR J1636-2354A. Inspecting the 8-year Fermi–LAT catalogue, we found a γ-ray source, 4FGL J1836.8–2354, with a positional uncertainty consistent with the globular cluster, but not with the radio position of the millisecond pulsar.
A new grade of ethylene-chlorotrifluoroethylene, low melting point HALAR® ECTFE (LMP ECTFE), was studied and used as a polymer for the preparation of solvent-resistant flat-sheet membranes. Among the ...different types of non-toxic solvents tested, di-ethyl adipate (DEA) was selected for preparing flat sheet membranes
via
thermally induced phase separation (TIPS). The morphology of the membranes has been analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Dense and porous membranes have been obtained and characterized by contact angle, pore size and porosity tests. Porous membranes showed an asymmetric structure made of a denser top-side and a spherulitic porous structure on the bottom side. Membrane resistance was studied using the dense membrane in contact with most aggressive organic solvents, such as polar protic, polar aprotic and non-polar solvents. The results suggest that the newly developed LMP ECTFE membranes are very promising candidates for organic solvent separation. Ultrafiltration (UF) and nanofiltration (NF) tests with alcohols and di-methyl formamide (DMF) demonstrated their solvent separation potential.
A new grade of ethylene-chlorotrifluoroethylene, low melting point HALAR® ECTFE (LMP ECTFE), was studied and used as a polymer for the preparation of solvent-resistant flat-sheet membranes.
We analysed a 115-ks XMM–Newton observation and the stacking of 8 d of INTEGRAL observations, taken during the raise of the 2015 outburst of the accreting millisecond X-ray pulsar SAX J1748.9−2021. ...The source showed numerous type-I burst episodes during the XMM–Newton observation, and for this reason we studied separately the persistent and burst epochs. We described the persistent emission with a combination of two soft thermal components, a cold thermal Comptonization component (∼2 keV) and an additional hard X-ray emission described by a power law (Γ ∼ 2.3). The continuum components can be associated with an accretion disc, the neutron star (NS) surface and a thermal Comptonization emission coming out of an optically thick plasma region, while the origin of the high-energy tail is still under debate. In addition, a number of broad (σ = 0.1–0.4 keV) emission features likely associated with reflection processes have been observed in the XMM–Newton data. The estimated 1.0–50 keV unabsorbed luminosity of the source is ∼5 × 1037 erg s−1, about 25 per cent of the Eddington limit assuming a 1.4 M⊙ NS. We suggest that the spectral properties of SAX J1748.9−2021 are consistent with a soft state, differently from many other accreting X-ray millisecond pulsars which are usually found in the hard state. Moreover, none of the observed type-I burst reached the Eddington luminosity. Assuming that the burst ignition and emission are produced above the whole NS surface, we estimate an NS radius of ∼7–8 km, consistent with previous results.
Purpose
This study is aimed at analyzing clinical outcome, absence of stroke recurrence, revascularization, and complications and long-term follow-up in the surgical treatment of moyamoya angiopathy ...(MMA) using the multiple burr holes (MBH) technique with dura opening and arachnoid preservation as a single procedure. To the best of our knowledge, this is the first to describe an MBH technique with arachnoid preservation.
Method
We retrospectively reviewed all patients operated from June 2001 to March 2021, for a symptomatic and progressive MMA operated with opening of the dura but arachnoid preservation. Clinical examinations were obtained in all patients, and radiological monitoring was performed by cerebral 3D-magnetic resonance angiography (MRA) with perfusion or single-photon emission computed tomography (SPECT) with acetazolamide.
Results
In total, 21 consecutive patients (6 children and 15 adults) were included with a mean age of 7.4 years in the pediatric group and 36.9 years in the adult group. Initial presentation was permanent ischemic stroke in 15 cases, transient ischemic attack (TIA) in 5 cases, and cerebral hemorrhage in one case. The MBH with dura opening and arachnoid preservation was performed bilaterally in 9 cases (43%) and unilaterally in 12 cases (57%). One patient died due to intraoperative bilateral ischemic stroke. Of the 20 other patients, 30% demonstrated clinical stability and 70% showed partial or complete recovery. Although one patient experienced a perioperative stroke, we did not observe any pseudomeningocele or postoperative ischemic stroke (IS) recurrence in all surviving cases during the average follow-up period of 55.5 months (range: 1–195). These outcomes emphasize the importance of preoperative monitoring to ensure the effectiveness and safety of the intervention. Postoperative angiography studies showed revascularization in 96.3% of treated hemispheres (100% in the adult group vs 80% in the pediatric group).
Conclusions
Our results on this small cohort suggest that the MBH technique with opening of the dura and arachnoids preservation can prevent recurrent strokes and reduce the risk of pseudomeningocele.
ABSTRACT
Ultraluminous X-ray sources (ULXs) are the most extreme among X-ray binaries in which the compact object, a neutron star or a black hole, accretes matter from the companion star, and exceeds ...a luminosity of $10^{39} \ \rm erg \, s^{-1}$ in the X-ray energy band alone. Despite two decades of studies, it is still not clear whether ULX spectral transitions are due to stochastic variability in the wind or variations in the accretion rate or in the source geometry. The compact object is also unknown for most ULXs. In order to place constraints on to such scenarios and on the structure of the accretion disc, we studied the temporal evolution of the spectral components of the variable source NGC 55 ULX-1. Using recent and archival data obtained with the XMM-Newton satellite, we modelled the spectra with two blackbody components which we interpret as thermal emission from the inner accretion flow and the regions around or beyond the spherization radius. The luminosity–temperature (L–T) relation of each spectral component agrees with the L ∝ T4 relationship expected from a thin disc model, which suggests that the accretion rate is close to the Eddington limit. However, there are some small deviations at the highest luminosities, possibly due to an expansion of the disc and a contribution from the wind at higher accretion rates. Assuming that such deviations are due to the crossing of the Eddington or supercritical accretion rate, we estimate a compact object mass of 6–14 M⊙, favouring a stellar-mass black hole as the accretor.
The NUSES space mission De Mitri, I.; Di Santo, M.
Journal of physics. Conference series,
02/2023, Letnik:
2429, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
NUSES is a new space mission aiming to test innovative observational and technological approaches related to the study of low energy cosmic and gamma rays, high energy astrophysical ...neutrinos, Sun-Earth environment, Space weather and magnetosphere-ionosphere-lithosphere coupling (MILC). The satellite will host two payloads, named TERZINA and ZIRÉ. ZIRÉ will perform measurements of electrons, protons and light nuclei from few up to hundreds of MeV, also testing new tools for the detection of cosmic MeV photons, and monitoring of MILC signals. TERZINA will observe the Cherenkov light produced by EAS generated by cosmic ray primaries at very high energies and will monitor the light emissions from the Earth limb in the near UV and visible ranges at the ns time scale, thus testing the observational concept of detecting Earth skimming astrophysical high energy neutrinos. The scientific objectives and development status of the mission will be presented.
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