VISIR-VLT high resolution study of the extended emission of four obscured post-AGB candidates

The onset of the asymmetry of planetary nebulae (PNe) is expected to occur during the late Asymptotic Giant Branch (AGB) and early post-AGB phases of low- and intermediate-mass stars. Among all post-AGB objects, the most heavily obscured ones might have escaped the selection criteria of previous studies detecting extreme axysimmetric structures in young PNe. Since the most heavily obscured post-AGB sources can be expected to descend from the most massive PN progenitors, these should exhibit clear asymmetric morphologies. We have obtained VISIR-VLT mid-IR images of four heavily obscured post-AGB objects barely resolved in previous Spitzer IRAC observations to analyze their morphology and physical conditions across the mid-IR. The VISIR-VLT images have been deconvolved, flux calibrated, and used to construct RGB composite pictures as well as color and optical depth maps that allow us to study the morphology and physical properties of the extended emission of these sources. We have detected extended emission from the four objects in our sample and resolved it into several structural components that are greatly enhanced in the temperature and optical depth maps. They reveal the presence of asymmetry in three young PNe (IRAS 15534-5422, IRAS 17009-4154, and IRAS 18454+0001), where the asymmetries can be associated with dusty torii and slightly bipolar outflows. The fourth source (IRAS 18229-1127), a possible post-AGB star, is better described as a rhomboidal detached shell. The heavily obscured sources in our sample do not show extreme axisymmetric morphologies. This is at odds with the expectation of highly asymmetrical morphologies in post-AGB sources descending from massive PN progenitors. The sources presented in this paper may be sampling critical early phases in the evolution of massive PN progenitors, before extreme asymmetries develop.Comment: 9 pages, 4 figure

Temperature and thickness dependence of the thermal conductivity in 2D ferromagnet Fe3_3GeTe2_2

The emergence of symmetry-breaking orders such as ferromagnetism and the weak interlayer bonding in van der Waals materials, offers a unique platform to engineer novel heterostructures and tune transport properties like thermal conductivity. Here, we report the experimental and theoretical study of the cross-plane thermal conductivity, $\kappa_\perp$, of the van der Waals 2D ferromagnet Fe$_3$GeTe$_2$. We observe a non-monotonic increase of $\kappa_\perp$ with the thickness and a large suppression in artificially-stacked layers, indicating a diffusive transport regime with ballistic contributions. These results are supported by the theoretical analyses of the accumulated thermal conductivity, which show an important contribution of phonons with mean free paths between 10 and 200 nm. Moreover, our experiments show a reduction of the $\kappa_\perp$ in the low-temperature ferromagnetic phase occurring at the magnetic transition. The calculations show that this reduction in $\kappa_\perp$ is associated with a decrease in the group velocities of the acoustic phonons and an increase in the phonon-phonon scattering of the Raman modes that couple to the magnetic phase. These results demonstrate the potential of van der Waals ferromagnets for thermal transport engineering

Reseñas

Reseñas de las siguientes obras: Guía del lector; The role of national libraries: a reassesment por Maurice B. Une; Management by objectives por Ceorge S. Odióme; The moving finger "accesses" por Susan Spaeth Cherry; SCICON comes to San José por Richard E. Rendier; Library of Congress information bulletin, 1981; Zero-base budgeting and the management of library change por Lois Jennings.Departamento de Bibliotecologí

Reseñas

Reseñas de las siguientes obras: Guía del lector; The role of national libraries: a reassesment por Maurice B. Une; Management by objectives por Ceorge S. Odióme; The moving finger "accesses" por Susan Spaeth Cherry; SCICON comes to San José por Richard E. Rendier; Library of Congress information bulletin, 1981; Zero-base budgeting and the management of library change por Lois Jennings.Departamento de Bibliotecologí

Reseñas

Reseñas de las siguientes obras: Guía del lector; The role of national libraries: a reassesment por Maurice B. Une; Management by objectives por Ceorge S. Odióme; The moving finger "accesses" por Susan Spaeth Cherry; SCICON comes to San José por Richard E. Rendier; Library of Congress information bulletin, 1981; Zero-base budgeting and the management of library change por Lois Jennings.Departamento de Bibliotecologí

Quantitative determination of c-myc facilitates the assessment of prognosis of OSCC patients

Myc genes are a family of proto-oncogenes whose proteins are implicated in the regulation of cell proliferation, differentiation and apoptosis, and in regulating the activity of genes involved in cell division. The aim of the present study was to establish a quantitative description of the expression of c-myc and evaluate its relationship with other clinical and prognostic factors, as well as to establish a multivariate survival prediction model. This is a retrospective study of 68 patients diagnosed with oral squamous cell carcinoma (OSCC). We constructed a tissue microarray for investigating the expression of c-myc by immunohistochemistry. Statistical analyses were carried out, and a multivariate model that predicts survival was established. The average expression of c-myc was 50.32 (SD, 26.05) with a range from 6.60 to 99.48; similar for initial and advanced tumor stages. Non-smoking patients had higher levels of c-myc, showing statistically significant differences (Kruskal-Wallis chi2=5.975; p=0.05). We found no statistically significant relationship between the quantitative expression of c-myc and any other clinical or pathological parameters. For each unit of increase of c-myc, the risk increased by 1.15 (p<0.001; HR, 1.150; 95% CI, 1062-1245). Further study of this protein, which may have a significant diagnostic, prognostic and therapeutic value is warranted. Its determination can be valuable when used together with other markers to assess the prognosis of OSCC patients

Ozone Eliminates SARS-CoV-2 from Difficult-to-Clean Office Supplies and Clinical Equipment.

Background: Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) continues to cause profound health, economic, and social problems worldwide. The management and disinfection of materials used daily in health centers and common working environments have prompted concerns about the control of coronavirus disease 2019 (COVID-19) infection risk. Ozone is a powerful oxidizing agent that has been widely used in disinfection processes for decades. The aim of this study was to assess the optimal conditions of ozone treatment for the elimination of heat-inactivated SARS-CoV-2 from office supplies (personal computer monitors, keyboards, and computer mice) and clinical equipment (continuous positive airway pressure tubes and personal protective equipment) that are difficult to clean. (2) Methods: The office supplies and clinical equipment were contaminated in an area of 1 cm2 with 1 × 104 viral units of a heat-inactivated SARS-CoV-2 strain, then treated with ozone using two different ozone devices: a specifically designed ozonation chamber (for low–medium ozone concentrations over large volumes) and a clinical ozone generator (for high ozone concentrations over small volumes). SARS-CoV-2 gene detection was carried out using quantitative real-time polymerase chain reaction (RT-qPCR). (3) Results: At high ozone concentrations over small surfaces, the ozone eliminated SARS-CoV-2 RNA in short time periods—i.e., 10 min (at 4000 ppm) or less. The optimum ozone concentration over large volumes was 90 ppm for 120 min in ambient conditions (24 °C and 60–75% relative humidity). (4) Conclusions: This study showed that the appropriate ozone concentration and exposure time eliminated heat-inactivated SARS-CoV-2 RNA from the surfaces of different widely used clinical and office supplies, decreasing their risk of transmission, and improving their reutilization. Ozone may provide an additional tool to control the spread of the COVID-19 pandemic.TRUEInstituto de Salud Carlos III, Madrid, Spain, and by the European Regional Development Funds (FEDER)Fundación Canaria del Instituto de Investigación Sanitaria de Canarias (FIISC), Las PalmasFundación Mapfre Guanarteme, Las PalmasGobierno de Canarias, Las Palmaspu

Monitoring SARS-CoV-2 variant transitions using differences in diagnostic cycle threshold values of target genes

Monitoring the emergence of new SARS-CoV-2 variants is important to detect potential risks of increased transmission or disease severity. We investigated the identification of SARS-CoV-2 variants from real-time reverse transcriptase polymerase chain reaction (RT-PCR) routine diagnostics data. Cycle threshold (Ct) values of positive samples were collected from April 2021 to January 2022 in the Northern Metropolitan Area of Barcelona (n = 15,254). Viral lineage identification from whole genome sequencing (WGS) was available for 4618 (30.3%) of these samples. Pairwise differences in the Ct values between gene targets (ΔCt) were analyzed for variants of concern or interest circulating in our area. A specific delay in the Ct of the N-gene compared to the RdRp-gene (ΔCt) was observed for Alpha, Delta, Eta and Omicron. Temporal differences in ΔCt correlated with the dynamics of viral replacement of Alpha by Delta and of Delta by Omicron according to WGS results. Using ΔCt, prediction of new variants of concern at early stages of circulation was achieved with high sensitivity and specificity (91.1% and 97.8% for Delta; 98.5% and 90.8% for Omicron). Thus, tracking population-wide trends in ΔCt values obtained from routine diagnostics testing in combination with WGS could be useful for real-time management and response to local epidemics

Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure