Simple Disk Research Articles

Molecular identification and antimicrobial resistance patterns of enterobacterales in community urinary tract infections among indigenous women in Ecuador: addressing microbiological misidentification

BackgroundAntibiotic resistance of Enterobacterales poses a major challenge in the treatment of urinary tract infections (UTIs). In low- and middle-income countries (LMICs), standard microbiological (i.e. urine culture and simple disk diffusion test) methods are considered the “gold standard” for bacterial identification and drug susceptibility testing, while PCR and DNA sequencing are less commonly used. In this study, we aimed to re-identifying Enterobacterales as the primary bacterial agents responsible for urinary tract infections (UTIs) by comparing the sensitivity and specificity of traditional microbiological methods with advanced molecular techniques for the detection of uropathogens in indigenous women from Otavalo, Ecuador.MethodsA facility-based cross-sectional study was conducted from October 2021 to February 2022 among Kichwa-Otavalo women. Pathogens from urine samples were identified using culture and biochemical typing. Morphological identification was doble-checked through PCR and DNA sequencing of 16S, recA, and rpoB molecular barcodes. The isolates were subjected to antimicrobial susceptibility-testing using disk diffusion test.ResultsThis study highlighted a 32% misidentification rate between biochemical and molecular identification. Using traditional methods, E. coli was 26.19% underrepresented meanwhile Klebsiella oxytoca was overrepresented by 92.86%. Furthermore, the genera Pseudomonas, Proteus, and Serratia were confirmed to be E. coli and Klebsiella spp. by molecular method, and one Klebsiella spp. was reidentified as Enterobacter spp. The susceptibility profile showed that 59% of the isolates were multidrug resistant strains and 31% produced extended spectrum beta-lactamases (ESBLs). Co-trimoxazole was the least effective antibiotic with 61% of the isolates resistant. Compared to previous reports, resistance to nitrofurantoin and fosfomycin showed an increase in resistance by 25% and 15%, respectively.ConclusionsCommunity-acquired UTIs in indigenous women in Otavalo were primarily caused by E. coli and Klebsiella spp. Molecular identification (16S/rpoB/recA) revealed a high rate of misidentification by standard biochemical and microbiological techniques, which could lead to incorrect antibiotic prescriptions. UTI isolates in this population displayed higher levels of resistance to commonly used antibiotics compared with non-indigenous groups. Accurate identification of pathogens causing UTIs and their antibiotic susceptibility in local populations is important for local antibiotic prescribing guidelines.

Badminton birdie-like aerodynamic alignment of drifting dust grains by subsonic gaseous flows in protoplanetary discs

ABSTRACT Recent (sub)millimetre polarization observations of protoplanetary discs reveal toroidally aligned, effectively prolate dust grains large enough (at least $\sim 100$$\mu$m) to efficiently scatter millimetre light. The alignment mechanism for these grains remains unclear. We explore the possibility that gas drag aligns grains through gas–dust relative motion when the grain’s centre of mass is offset from its geometric centre, analogous to a badminton birdie’s alignment in flight. A simple grain model of two non-identical spheres illustrates how a grain undergoes damped oscillations from flow-induced restoring torques which align its geometric centre in the flow direction relative to its centre of mass. Assuming specular reflection and subsonic flow, we derive an analytical equation of motion for spheroids where the centre of mass can be shifted away from the spheroid’s geometric centre. We show that a prolate or an oblate grain can be aligned with the long axis parallel to the gas flow when the centre of mass is shifted along that axis. Both scenarios can explain the required effectively prolate grains inferred from observations. Application to a simple disc model shows that the alignment time-scales are shorter than or comparable to the orbital time. The grain alignment direction in a disc depends on the disc (sub-)structure and grain Stokes number (St) with azimuthal alignment for large St grains in sub-Keplerian smooth gas discs and for small St grains near the gas pressure extrema, such as rings and gaps.

Photosynthetic Responses to Salt Stress in Two Rice (Oryza sativa L.) Varieties

Assessing salt tolerance in plants under field conditions is a challenging task. The objective of this research was to assess the effectiveness of different methods (leaf disc assay and pot experiment) for evaluating salt tolerance in rice. Using two varieties with different salt tolerance, Changmaogu (CM) and 9311, under three NaCl levels (0, 0.3%, and 1.0%), we evaluated the photosynthetic performance in terms of chlorophyll content in leaf disc assays, as well as the photosynthetic rate (Pn), chlorophyll content, linear electron flow (LEF), and non-photochemical quenching (NPQ), in a semi-controlled pot experiment. In the leaf disc assay, CM showed a smaller decrease in chlorophyll content compared to 9311, especially under 1.0% salinity. Simultaneously, in the pot experiment, the CM variety employed flexible photosynthetic strategies, actively decreasing LEF and Pn after 5 days of salt stress (day 5) and then increasing photosynthetic capacity (chlorophyll content, LEF, and Pn) on day 10. Notably, the total chlorophyll content for the CM variety under 1.0% salinity was significantly higher than in the control, showing a 25.0% increase. Additionally, CM demonstrated NPQt sensitivity under 0.3% salinity, requiring an LEF of 150 to achieve an NPQt value of 3.0, compared to an LEF of 180 in the control. These results suggest that a simple leaf disc assay may not fully capture the adaptive mechanisms of rice plants under salinity stress. Therefore, we advocate for the use of more comprehensive methods, such as outdoor pot or field experiments, to gain a deeper understanding and more accurate evaluation of salt tolerance in rice.

Planet Formation Regulated by Galactic-scale Interstellar Turbulence

Planet formation occurs over a few Myr within protoplanetary disks of dust and gas, which are often assumed to evolve in isolation. However, extended gaseous structures have been uncovered around many protoplanetary disks, suggestive of late-stage infall from the interstellar medium (ISM). To quantify the prevalence of late-stage infall, we apply an excursion set formalism to track the local density and relative velocity of the ISM over the disk lifetime. We then combine the theoretical Bondi–Hoyle–Lyttleton (BHL) accretion rate with a simple disk evolution model, anchoring stellar accretion timescales to observational constraints. Disk lifetimes, masses, stellar accretion rates, and gaseous outer radii as a function of stellar mass and age are remarkably well reproduced by our simple model that includes only ISM accretion. We estimate that 20%−70% of disks may be mostly composed of material accreted in the most recent half of their lifetime, suggesting that disk properties are not a direct test of isolated evolution models. Our calculations indicate that BHL accretion can also supply sufficient energy to drive turbulence in the outer regions of protoplanetary disks with viscous α SS ∼ 10−5 to 10−1, although we emphasize that angular momentum transport and particularly accretion onto the star may still be driven by internal processes. Our simple approach can be easily applied to semianalytic models. Our results represent a compelling case for regulation of planet formation by large-scale turbulence, with broad consequences for planet formation theory. This possibility urgently motivates deep observational surveys to confirm or refute our findings.

Dissipative particle dynamics simulation and experimental studies of pseudo-gemini surfactants with different hydrophobic chain lengths

In this work new pseudo-gemini type surfactants are constructed via a simple, energy and material efficient way, using piperazine, propylene oxide and seven different fatty acids: capric, lauric, myristic, stearic, oleic and linolenic. The compounds are characterized by 1H NMR, 13C NMR and FTIR studies. Micellization and adsorption properties of the novel pseudo-gemini surfactants are investigated via surface tension and conductivity measurements. Antimicrobial properties are evaluated using the simple disk diffusion test method. Dissipative Particle Dynamics (DPD) simulations are performed to model aggregation behavior of the new pseudo-gemini surfactants. Experimental studies revealed that Critical Micelle Concentration (CMC) of the obtained pseudo-gemini surfactants are lower than 1 mmol/L. Theoretically calculated CMC values are slightly higher than experimental CMC values. However, overall, very good agreement between theoretical and experimental CMC values is observed. Radial Distribution Function (RDF) and radius of gyration (Rg) plots are analyzed to gain further insight into aggregation of the surfactant molecules in aqueous environment. The DPD model of the pseudo-gemini amphiphiles successfully predicts the most important traits of the aggregation process.

Constraining the stellar masses and origin of the protostellar VLA 1623 system

We present ALMA Band 7 molecular line observations of the protostars within the VLA 1623 system. We detect C17O (3–2) in the circumbinary disk around VLA 1623A and the outflow cavity walls of the collimated outflow. We further detect redshifted and blueshifted velocity gradients in the circumstellar disks around VLA 1623B and VLA 1623W that are consistent with Keplerian rotation. We used the radiative transfer modelling code pdspy and simple flared disk models to measure stellar masses of 0.27 ± 0.03 M⊙, 1.9−0.2+0.3 M⊙, and 0.64 ± 0.06 M⊙ for the VLA 1623A binary, VLA 1623B, and VLA 1623W, respectively. These results represent the strongest constraints yet on stellar mass for both VLA 1623B and VLA 1623W, and the first mass measurement for all stellar components using the same tracer and methodology. We use these masses to discuss the relationship between the young stellar objects (YSOs) in the VLA 1623 system. We find that VLA 1623W is unlikely to be an ejected YSO, as has been previously proposed. While we cannot rule out that VLA 1623W is a unrelated YSO, we propose that it is a true companion star to the VLA 1623A/B system and that these stars formed in situ through turbulent fragmentation and have had only some dynamical interactions since their inception.

Enhancing sensitivity towards electrochemical miRNA detection using an affordable paper-based strategy

In the era of liquid biopsy, microRNAs emerge as promising candidates for the early diagnosis and prognosis of cancer, offering valuable insights into the disease’s development. Among all the existing analytical approaches, even if traditional approaches such as the nucleic acid amplification ones have the advantages to be highly sensitive, they cannot be used at the point-of-care, while sensors might be poorly sensitive despite their portability. In order to improve the analytical performance of existing electroanalytical systems, we demonstrate how a simple chromatographic paper-based disk might be useful to rationally improve the sensitivity, depending on the number of preconcentration cycles. A paper-based electrochemical platform for miRNA detection has been developed by modifying a paper-based electrode with a methylene blue (MB)-modified single-stranded sequence (ssDNA) complementary to the chosen miRNA, namely miR-224 that is associated with lung cancer. A detection limit of ca. 0.6 nM has been obtained in spiked human serum samples. To further enhance the sensitivity, an external chromatographic wax-patterned paper-based disk has been adopted to preconcentrate the sample, and this has been demonstrated both in standard and in serum solutions. For each solution, three miR-224 levels have been preconcentrated, obtaining a satisfactory lowering detection limit of ca. 50 pM using a simple and sustainable procedure. This approach opens wide possibilities in the field of analytical and bioanalytical chemistry, being useful not only for electrochemistry but also for other architectures of detection and transduction.

Chromatically modeling the parsec-scale dusty structure in the center of NGC 1068

Context. The Very Large Telescope Interferometer (VLTI) has been providing breakthrough images of the dust in the central parsecs of active galactic nuclei (AGNs), which is thought to be a key component of the AGN unification scheme and AGN host galaxy interaction. In single infrared bands, these images can enjoin multiple interpretations, some of which could challenge the unification scheme. This is the case for the archetypal type 2 AGN of NGC 1068, whereby the degeneracy is reduced by multi-band temperature maps that are hindered by an ambiguity in the alignment between different single-band images. Aims. We aim to solve this problem by creating a chromatic model capable of simultaneously explaining the VLTI GRAVITY+MATISSE 2 μm–13 μm observations of AGNs hosted by NGC 1068. Methods. We employed a simple disk and wind geometry populated by spherical black-body emitters and dust obscuration to create a versatile multi-wavelength modelling method for chromatic IR interferometric data of dusty objects. Results. This simple geometry is capable of reproducing the spectro-interferometric data of NGC 1068 from the K through N bands. It explains the complex single band images with obscuration and inclination effects, and it solves the alignment problem between bands. We find that the resulting model disk and wind geometry is consistent with previous studies of comparable and larger scales. For example, compared to molecular gas emission, our model wind position angle (PA) of 2322° is close to the mas-scale outflowing CO(6–5) PA of ∼33° seen with ALMA. The equivalent 90° offset model disk PA is also consistent with the CO(6–5) disk axis of 112° as well as the mas-scale disk axis from CO(2–1), CO(3–2), and HCO+(4–3) of 115 ± 5°. Furthermore, the resulting model images visually resemble the multiple achromatic image reconstructions of the same data when evaluated at the same wavelengths. We conclude that the IR emitting structure surrounding the AGN within NGC 1068 can indeed be explained by the clumpy disk+wind iteration of the AGN unification scheme. Within the scheme, we find that it is best explained as a type 2 AGN and the obscuring dust chemistry can be explained by a mix of olivine silicates and 16 ± 1% amorphous carbon.

The need for spatially resolved observations of polycyclic aromatic hydrocarbons in protoplanetary discs

Context. The signatures of polycyclic aromatic hydrocarbons (PAHs) have been observed in protoplanetary discs, and their emission features obtained from spectral energy distributions (SED) have been used in the literature to characterise their size and determine their abundance. Aims. Two simple disc models (uniform PAH distribution against a PAH gap in the inner disc) are compared to investigate the difference of their SED and obtainable information. Methods. We used the radiative transfer code RADMC-3D to model the SED of two protoplanetary discs orbiting a typical Herbig star, one of which features a depletion of PAHs in the inner disc. We further created artificial images of the discs at face-on view to extract radial profiles of the PAH emission in the infrared. Results. We find that the extracted PAH features from an SED provide limited information about the PAHs in protoplanetary disc environments, except for the ionisation state. The distribution of PAHs in a protoplanetary disc influences the total observed PAH luminosity in a non-linear fashion and alters the relative strength between the 3.3 µm and 11.3 µm features. Furthermore, we produced radial profiles at the 3 µm, 6 µm and, 11 µm PAH emission features and find that they follow a double power-law profile where the slope reflects the radiative environment (single photon regime vs. multi-photon regime) in which the PAHs lie. Conclusions. Using spatially resolved techniques such as IFU or imaging in the era of the James Webb Space Telescope, we find that multi-wavelength radial emission profiles will not only provide information on the spatial distribution of the PAHs, but may also provide information on their size and underlying UV environment, which is crucial for photo-evaporative disc wind models.

Implementation of a Simple Actuator Disk for Large-Eddy Simulation in the Weather Research and Forecasting Model (WRF-SADLES v1.2) for wind turbine wake simulation

Abstract. In this study, we present the development of a Simple Actuator Disk model for Large-Eddy Simulation (SADLES), implemented within the Weather Research and Forecasting (WRF) model, which is widely used in atmospheric research. The WRF-SADLES model supports both idealized studies and realistic applications through downscaling from realistic data, with a focus on resolutions of tens of meters. Through comparative analysis with the Parallelized Large-eddy Simulation Model (PALM) at resolutions of 10 and 30 m, we validate the effectiveness of WRF-SADLES in simulating the wake characteristics of a 5 MW wind turbine. Results indicate good agreement between WRF-SADLES at 30 m resolution and 10 m resolution and the PALM model. Additionally, we demonstrate a practical case study of WRF-SADLES by downscaling ERA5 reanalysis data using a nesting method to simulate turbine wakes at the Alpha Ventus wind farm in the south of the North Sea. The meso-to-micro downscaling simulation reveals that the wake effect simulated by WRF-SADLES at the FINO1 offshore meteorological mast station aligns well with the cup anemometer and lidar measurements. Furthermore, we investigate an event of farm-to-farm interaction, observing a 16 % reduction in ambient wind speed and a 38 % decrease in average turbine power at Alpha Ventus due to the presence of a wind farm to the southwest. WRF-SADLES offers a promising balance between computational efficiency and accuracy for wind turbine wake simulations, making it valuable for wind energy assessments and wind farm planning.

Operational Deflection Shape Measurements on Bladed Disks with Continuous Scanning Laser Doppler Vibrometry.

The continuous scanning laser Doppler vibrometry (CSLDV) technique is usually used to evaluate the vibration operational deflection shapes (ODSs) of structures with continuous surfaces. In this paper, an extended CSLDV is demonstrated to measure the non-continuous surface of the bladed disk and to obtain the ODS efficiently. For a bladed disk, the blades are uniformly distributed on a given disk. Although the ODS of each blade can be derived from its response data along the scanning path with CSLDV, the relative vibration direction between different blades cannot be determined from those data. Therefore, it is difficult to reconstruct the complete vibration mode of the whole blade disk. In order to measure the complete ODS of the bladed disk, a method based on ODS frequency response functions (ODS FRFs) has been proposed. While the ODS of each blade is measured by designing the suitable scanning paths in CSLDV, an additional response signal is obtained at a fixed point as the reference signal to identify the relative vibration phase between the blade and the blade of the bladed disk. Finally, a measurement is performed with a simple bladed disk and the results demonstrate the feasibility and effectiveness of the proposed extended CSLDV method.

Efficacy and Advantages of Spinal Anesthesia in Lumbar Disk Surgery.

Quality of life (QoL) may be affected due to various reasons such as low back or leg pains with accompanying neurologic problems. Lumbar disk surgery is one of the most common performed surgeries to relieve those symptoms. Various anesthetic techniques can be used safely to perform lumbar disk surgeries. Properties that make an anesthetic technique good are mainly the quick onset and returning of the effects. This large retrospective study with patients who have undergone lumbar disk surgery under spinal anesthesia aims to evaluate the perioperative and postoperative parameters of the spinal anesthesia and review the literature. Cases operated under spinal anesthesia between January 2017 and December 2020 were investigated, and 617 patients who underwent simple lumbar disk surgery were included in the study. Demographic characteristics and American Society of Anesthesiologists (ASA) physical status of the patients were recorded. Visual analog scale (VAS) and QoLscores were obtained before and after the operation. There were 282 (45.7%) male and 335 (54.3%) female patients with a mean age of 39.48 ± 16.71 years (range: 18-58 years) at symptom onset. The mean operating time was 46.3 minutes (range: 22-68 minutes). Average blood loss was 85 mL (range: 55-125 mL). All the patients were mobilized 6 to 12 hours after surgery. In our patient group, there were both high- and normal-risk groups in terms of the ASA physical status. During the clinical follow-up, a statistically significant improvement was found for the VAS and QoL scores (p < 0.05). In this large retrospective study, our results have confirmed that spinal anesthesia is at least comparable to general anesthesia and even superior to it in some aspects.

Lychee peel extract-based magnetic iron oxide nanoparticles: Sustainable synthesis, multifaceted antioxidant system, and prowess in eco-friendly food preservation

The quest for sustainable synthesis methods has led to the exploration of lychee peel extract (LCPEx) as an eco-friendly alternative in the field of nanomaterials. This groundbreaking study introduces the synthesis of lychee peel extract-based magnetic iron oxide nanoparticles (LCPEx-MIONPs) and delves into their diverse applications. The meticulous methodology involved a multistep process for lychee peel extraction, resulting in the creation of LCPEx. The subsequent synthesis of LCPEx-MIONPs, achieved by combining the extract with iron chloride as a precursor and sodium hydroxide as a pH adjustor (set to 7.5), yielded nanoparticles with nanoscale dimensions (8.7± 0.4 nm) and diverse morphologies (cubic, hexagonal, spherical). Comprehensive characterization techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), unveiled the structural attributes of LCPEx-MIONPs. The LCPEx exhibited robust antioxidant activity against DPPH, reaching its maximum inhibitory within only 5 minutes in a simple disc diffusion. The multifaceted antioxidant system of LCPEx-MIONPs exhibited an IC50 value of 202.3 µg/mL, highlighting the synergistic effects of lychee phytochemicals and magnetic ions. Beyond antioxidant capabilities, LCPEx-MIONPs, when incorporated into banana-based food preservation films, demonstrated significant prowess in grape preservation. The controlled release properties led to a notable reduction in water loss (9.3% on day 3 and 19.7% on day 6) compared to control grapes without LCPEx-MIONPs incorporated (18.2% on day 3 and 34.8% on day 6). This study significantly contributes to green nanotechnology, food preservation, and the development of eco-friendly hydrogels and bioplastic films, emphasizing the versatile applications of LCPEx-MIONPs in antioxidants, sustainable food preservation, and hydrogel-based bioplastics.

Heuristic Incremental Theory of Diffraction for a Wedge with Impedance Surfaces

This paper proposes a novel incremental theory of diffraction (ITD) formulation to calculate the fringe field from a wedge characterized by impedance surfaces and arbitrary exterior angles. The ITD formula was originally based on the Fourier transform pair relationship between the solution for the canonical wedge problem and incremental field contribution. However, this procedure can be utilized to report the ITD formula only for planar and half-planar impedance surfaces. Therefore, this paper develops a heuristic ITD formula by conceptually deriving the incremental diffracted field contribution from the uniform theory of diffraction coefficient and inferring the physical optics edge-diffracted field contribution from the terms related to the incidence shadow and reflection shadow boundaries. The proposed formula is applied to simple triangular impedance cylinder and disk models with impedance surfaces, and the results are compared with those of the method-of-moment and VIRAF’s ITD solver to show that is performs similar to the former and better than the latter.

Clinical study on the treatment of postoperative recurrence of lumbar disc herniation with intervertebral fusion

To explore clinical effect of different intervertebral fusion devices (cage) in treating postoperative recurrent lumbar disc herniation (LDH). One hundred and forty-two LDH patients with recurrence after simple intervertebral disc nucleus pulpoideectomy from January 2019 to January 2021 were retrospectively analyzed. All patients were treated with combined underchannel fixation and interbody fusion and divided into a single anatomical group,two-anatomical group and a single banana group according to types and numbers of implanted cage. There were 51 patients in a single anatomical group,included 29 males and 22 females,aged from 39 to 65 years old with an average of (53.74±5.68) years old;body mass index (BMI) ranged from 18.62 to 28.13 kg·m-2 with an average of (22.08±2.15) kg·m-2;the interval between operation and recurrence ranged from 0.5 to 4.0 years with an average of (2.7±0.8) years;5 patients with L3,4,35 patients with L4,5 and 11 patients with L5S1;a single anatomical cage was implanted. There were 46 patients in two-anatomical group,included 25 males and 21 females,aged from 37 to 66 years old with an average of (54.52±6.02) years old;BMI ranged from 18.25 to 28.44 kg·m-2 with an average of (21.74±1.83) kg·m-2;the interval between operation and recurrence ranged from 0.5 to 5.0 years with an average of (2.7±0.9) years;4 patients with L3,4,32 patients with L4,5 and 10 patients with L5S1;two-anatomical cages were implanted. There were 45 patients in a single banana group,included 22 males and 23 females,aged from 38 to 65 years old with an average of (54.49±6.45) years old;BMI ranged from 18.85 to 28.20 kg·m-2 with an average of (21.63±1.59) kg·m-2;the interval between operation and recurrence ranged from 0.5 to 5.0 years with an average of (2.6±1.0) years;3 patients with L3,4,36 patients with L4,5 and 16 patients with L5S1;a single banana cage was implanted. Operation time,intraoperative blood loss,incision length,postoperative incision drainage volume,hospital stay and complications among 3 groups were observed and compared. The height of intervertebral space before and after operation,curvature of lordosis and the postoperative intervertebral fusion were compared. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to evaluate degree of lumbar pain and lumbar function before operation,1 and 6 months after operation,respectively. All patients among 3 groups were followed up at least 6 months,and no cases were fell out. There were no significant difference in operation time,intraoperative blood loss,incision length,postoperative incision drainage volume and hospital stay among 3 groups (P>0.05). At 6 months after operation,the height of intervertebral space in two-anatomical group and a single group were [(11.08±1.78) mm,(10.95±1.62) mm],curvature of lordosis were [(12.05±1.86) °,(11.63±1.57) °],which were higher than those in a single dissection group (10.14±1.54) mm,(10.92±1.45) °,and the difference were statistically significant (P<0.05). The interbody fusion rate between two-anatomical and a banana group (95.65%,95.56%) were higher than that in a single anatomical group (78.43%) at 6 months after operation (P<0.05). VAS and ODI of lumbar among 3 groups were decreased at 1 and 6 months after operation (P<0.05). There was no significant difference in complications among 3 groups (P>0.05). The three fusion devices could achieve significant results in treating postoperative recurrence of LDH,but the implantation of two-anatomical cage and a single banana cage are more helpful to maintain the height of intervertebral space and lordosis curvature of patients with postoperative recurrence of LDH,and obtain good intervertebral fusion results.

GIARPS High-resolution Observations of T Tauri stars (GHOsT)

Aims. This paper aims to revisit the kinematical and physical properties of the warm (T ~ 5000–10 000 K) atomic gas in the inner disk (&lt;5 au) region of classical T Tauri stars (CTTs) and relate them to the properties of the outer dusty disk resolved with ALMA. We also want to define constraints for the mass-loss in the inner atomic winds and jets to assess their role in the evolution and dispersal of planet-forming disks. Methods. We used the high resolution (R = 115 000, ~2.6 km s−1) spectra of 36 CTTs observed as part of the GIARPS High-resolution Observations of T Tauri stars (GHOsT) project and analysed the profile and luminosity of the brightest optical forbidden lines, namely [O I] 630 nm, [O I] 557 nm, [S II] 406 nm, [S II] 673 nm, and [N II] 658 nm. Results. We decomposed the line profiles into different velocity components, and concentrated our analysis mostly on the so-called narrow low-velocity component (NLVC). We find that about 40% of sources display a NLVC peak velocity (Vp) compatible with the stellar velocity. These include the transitional disks (TD) and typically show a single low velocity component (LVC), lower mass accretion rates, and the absence of a jet. They therefore might represent later evolutionary stages where the emission from the disk is dominant with respect to the wind contribution. No difference in kinematical properties was instead found between sources with full disks and disks with substructures as resolved by ALMA. The [O I] 630 nm profiles peaking at the stellar velocity are well fitted by a simple Keplerian disk model, where the emission line region extends from ~0.01 au up to several tens of au in some cases. The [O I] emission is detected inside the sub-millimetre dust cavities of all the TDs. No correlation is found between Rkep, derived from the line half width at half maximum (HWHM), and the size of the dust cavity. We see an anti-correlation between the [O I] 557/630 nm ratio and Rkep, which suggests that the [O I] emitting region expands as the gas dominating the emission cools and becomes less dense. We confirmed previous findings that the line ratios observed in the LVC, if compared with a thermal single temperature and density model, imply ne ~ 106–108 cm−3 and Te ~ 5000–10 000 K, and additionally constrained the ionisation fraction in the NLVC to be xe &lt; 0.1. We however discuss the limits of applying this diagnostic to winds that are not spatially resolved. Conclusions. The emission from the disk should be considered as an important contribution to the forbidden line emission in CTTs. Also, the clearing of warm atomic gas from the upper disk layers does not seem to follow the dispersal of the bulk of molecular gas and dust during late disk evolution. For the outflow component, we estimated the mass-loss for both the disk winds and jets. We conclude that without better knowledge of the wind geometry and spatial extent, and given the limitation of the diagnostics, the mass-loss rates in the wind traced by the blue shifted LVC cannot be constrained better than a factor of 100, with a Ṁwind/Ṁacc spanning between ~0.01 and more than 1. When compared with synthetic [O I] 630 nm images of X-ray photoevaporation models, the estimated Ṁwind represents a lower limit to the total mass-loss rate of the model, indicating that [O I] 630 nm is likely not the best tracer to probe mass-loss in low-velocity winds.

Spectroastrometric Survey of Protoplanetary Disks with Inner Dust Cavities

We present high-resolution spectra and spectroastrometric (SA) measurements of fundamental rovibrational CO emission from nine nearby (≲300 pc) protoplanetary disks where large inner dust cavities have been observed. The emission-line profiles and SA signals are fit with a slab disk model that allows the eccentricity of the disk and intensity of the emission to vary as power laws. Six of the sources are well fit with our model, and three of these sources show asymmetric line profiles that can be fit by adopting a nonzero eccentricity. The three other sources have components in either their line profile or SA signal that are not captured by our disk model. Two of these sources (V892 Tau and CQ Tau) have multi-epoch observations that reveal significant variability. CQ Tau and AB Aur have CO line profiles with centrally peaked components that are similar to line profiles which have been interpreted as evidence of molecular gas arising from a wide-angle disk wind. Alternatively, emission from a circumplanetary disk could also account for this component. The interpretations of these results can be clarified in the future with additional epochs that will test the variability timescale of these SA signals. We discuss the utility of using high-resolution spectroscopy for probing the dynamics of gas in the disk and the scenarios that can give rise to profiles that are not fit with a simple disk model.

Impacts of the Local arm on the local circular velocity inferred from the Gaia DR3 young stars in the Milky Way

ABSTRACT A simple one-dimensional axisymmetric disc model is applied to the kinematics of O type and B type stars (OB stars) near the Sun obtained from Gaia Data Release 3 catalogue. The model determines the ‘local centrifugal speed’ Vc(R0) – defined as the circular velocity in the Galactocentric rest frame, where the star would move in a near-circular orbit if the potential is axisymmetric with the local potential of the Galaxy. We find that the Vc(R0) values and their gradient vary across the selected region of stars within the solar neighbourhood. By comparing with an N-body/hydrodynamic simulation of a Milky Way-like galaxy, we find that the kinematics of the young stars in the solar neighbourhood is affected by the Local arm, which makes it difficult to measure Vc(R0). However, from the resemblance between the observational data and the simulation, we suggest that the known rotational velocity gap between the Coma Bernices and Hyades-Pleiades moving groups could be driven by the co-rotation resonance of the Local arm, which can be used to infer the azimuthally averaged circular velocity. We find that Vc(R) obtained from the D &amp;lt; 2 kpc sample is well matched with this gap at the position of the Local arm. Hence, we argue that our results from the D &amp;lt; 2 kpc sample, Vc(R0) = 234 ± 2 km s−1, are close to the azimuthally averaged circular velocity rather than the local centrifugal speed, which is influenced by the presence of the Local arm.

Synthetic gravitational lens image of the Sagittarius A* black hole with a thin disc model

ABSTRACT The images of Sagittarius A* published by the Event Horizon Telescope (ETH) Collaboration in 2022 present features that were associated with an emission ring consistent with what is expected from an accretion disc surrounding the supermassive black hole at the centre of our Galaxy. Here, we generate images of Sgr A* across different configurations of a simple accretion disc model that became successful, in our previous work, in reproducing the main features observed in M87*. Their best image, here reproduced in Fig. 1, suggests a geometric configuration of an inclined disc with three bright regions; which we have considered as our first configuration. Since we were not convinced with the results of this first configuration, we also explore in detail the case of nearly edge-on orientations which are a priori the expected geometry for a relaxed disc, as seen from the plane of the Galaxy. We have produced simulated images using an efficient ray tracing and geodesic deviation methodology that allows to account for deformation, relativistic, and magnification effects. We compare our synthetic images with the EHT images reconstructed with data from April 6 and 7 of 2017. We found that, although the EHT Collaboration seems to discard the image from April 6, our best suggested image resembles the output from the themis pipeline for April 6; which for us gives support for the edge-on configuration.

Probing Disk Ice Content and Polycyclic Aromatic Hydrocarbon Emission through Multiband MagAO+Clio Images of HD 141569

We present resolved images of the inner disk component around HD 141569A using the Magellan adaptive optics system with the Clio2 1–5 μm camera, offering a glimpse of a complex system thought to be in a short evolutionary phase between protoplanetary and debris disk stages. We use a reference star along with the Karhunen–Loéve image projection (KLIP) algorithm for point-spread function subtraction to detect the disk inward to about 0.″24 (∼25 au assuming a distance of 111 pc) at high signal-to-noise ratios at L′ (3.8 μm), Ls (3.3 μm), and narrowband Ice (3.1 μm). We identify an arc or spiral arm structure at the southeast extremity, consistent with previous studies. We implement forward modeling with a simple disk model within the framework of a Markov Chain Monte Carlo sampler to better constrain the geometrical attributes and photometry using our KLIP-reduced disk images. We then leverage these modeling results to facilitate a comparison of the measured brightness in each passband to find a reduction in scattered light from the disk in the Ice filter, implying significant absorption due to water ice in the dust. Additionally, our best-fit disk models exhibit peak brightness in the southwestern, back-scattering region of the disk, which we suggest to be possible evidence of 3.3 μm polycyclic aromatic hydrocarbon emission. However, we point out the need for additional observations with bluer filters and more complex modeling to confirm these hypotheses.