Small-scale Interaction of Turbulence with Thermonuclear Flames in Type Ia Supernovae

Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr << 1, and laminar flame speed, S_L. We find that if S_L ~ u', where u' is the rms amplitude of turbulent velocity fluctuations, the local flame propagation speed does not significantly deviate from S_L even in the presence of velocity fluctuations on scales below the laminar flame thickness. This result is interpreted in the context of subgrid-scale modeling of supernova explosions and the mechanism for deflagration-detonation-transitions.Comment: 8 pages, 6 figures, accepted by Astrophys.

Elucidation of genetic diversity through Multivariate analysis in brinjal (Solanum melongena L.) landraces for varietal improvement

Genetic diversity plays a crucial role in harnessing the potential of crop genotypes for genetic improvement. It helps to identify, preserve, and utilize diverse landraces effectively. This research aimed to assess the level of genetic diversity and traits enhancing genetic variation among 46 brinjal genotypes (Solanum melongena L.) in preparation for a special breeding programme to utilize the potential landraces. Genetic divergence among 46 genotypes of brinjal for eleven characters was assessed using the D2 method. The studied genotypes were categorized into eight clusters. Cluster I with 15 genotypes was the largest followed by Cluster IV (14 genotypes), Cluster V (7 genotypes), Cluster VII (4 genotypes), Cluster III (3 genotypes), Clusters II, VI, and VIII with one genotype each. The intra-cluster D2 values ranged from 0.00 (Cluster II, VI and VII) to 103.53 (Cluster III). The inter-cluster distances varied from 117.00 to 791.17. Cluster II and Cluster VII had the greatest inter-cluster distance (791.17), followed by Cluster II and VIII (673.41), and Cluster VII and Cluster V had the smallest inter-cluster distance (117.00). Crossing genotypes in clusters with wide inter-cluster distances improves recombinant isolation in segregating generations. The three traits- number of flowers per inflorescence (23.8%), average fruit weight (17.68%) and days to first flowering (16.81%) altogether contribute to 57.8% of the total divergence. The combination of these traits could be useful to produce high-yielding climate resilient varieties from valuable landraces

Multi-satellite retrieval of single scattering albedo using the OMI–MODIS algorithm

Single scattering albedo (SSA) represents a unique identification of aerosol type and can be a determinant factor in the estimation of aerosol radiative forcing. However, SSA retrievals are highly uncertain due to cloud contamination and aerosol composition. The recent improvement in the SSA retrieval algorithm has combined the superior cloud-masking technique of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the higher sensitivity of the Ozone Monitoring Instrument (OMI) to aerosol absorption. The combined OMI–MODIS algorithm has only been validated over a small spatial and temporal scale. The present study validates the algorithm over global oceans for the period from 2008 to 2012. The geographical heterogeneity in the aerosol type and concentration over the Atlantic Ocean, the Arabian Sea and the Bay of Bengal was useful to delineate the effect of aerosol type on the retrieval algorithm. We also noted that OMI overestimated SSA when absorbing aerosols were present closer to the surface. We attribute this overestimation to data discontinuity in the aerosol height climatology derived from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. OMI uses predefined aerosol heights over regions where CALIPSO climatology is not present, leading to the overestimation of SSA. The importance of aerosol height was also studied using the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model. The results from the joint retrievals were validated using cruise-based measurements. It was seen that OMI–MODIS SSA retrievals performed better than the OMI only retrieval over the Bay of Bengal during winter, when the aerosols are present closer to the surface. Discrepancy between satellite retrievals and cruise measurements was seen when elevated aerosols were present which might not have been detected by the cruise instruments.</p

Impact of subsurface terric materials on the composition and behavior of histosols

Approximately 13% of the land area of Sarawak , Malaysia is covered by Histosols. Recent land and agricultural policies encourage utilization of Histosols for agricultural purposes to meet the national food requirements. Increasing stress on this ecosystem requires a better understanding of the resource and its behavior. Mineral terric substrata are common in many Histosols. A transect of 50 m at Kota Samarahan (Sarawak) was selected for this study to evaluate the impact of terric materials on the properties of the overlying organic tier. Six basic forms of subsurface discontinuities were recognized: symmetrical dome, asymmetrical dome, flat top, flat base, orthogonal and irregular. The degree of horizonation was different in all the soils. The pH of the soils was quite similar. All soils had net negative charges that increased with depth, however, the actual amounts of net charges varied between the soils. The soils had negligible amounts of exchangeable cations. The fiber contents, cation exchange capacities, FTIR spectra and Cue' adsorption studies showed critical differences. Despite the fact that these soils are mapped as one mapping unit, major differences in critical properties are expected to influence the behavior and performance. Variations in subsurface discontinuities cast some doubt on the reliability of conventional mapping techniques in such soils. The information generated is very useful to improve soil survey procedures and the subsequent use and management of these soils

Cloud microphysical effects of turbulent mixing and entrainment

Turbulent mixing and entrainment at the boundary of a cloud is studied by means of direct numerical simulations that couple the Eulerian description of the turbulent velocity and water vapor fields with a Lagrangian ensemble of cloud water droplets that can grow and shrink by condensation and evaporation, respectively. The focus is on detailed analysis of the relaxation process of the droplet ensemble during the entrainment of subsaturated air, in particular the dependence on turbulence time scales, droplet number density, initial droplet radius and particle inertia. We find that the droplet evolution during the entrainment process is captured best by a phase relaxation time that is based on the droplet number density with respect to the entire simulation domain and the initial droplet radius. Even under conditions favoring homogeneous mixing, the probability density function of supersaturation at droplet locations exhibits initially strong negative skewness, consistent with droplets near the cloud boundary being suddenly mixed into clear air, but rapidly approaches a narrower, symmetric shape. The droplet size distribution, which is initialized as perfectly monodisperse, broadens and also becomes somewhat negatively skewed. Particle inertia and gravitational settling lead to a more rapid initial evaporation, but ultimately only to slight depletion of both tails of the droplet size distribution. The Reynolds number dependence of the mixing process remained weak over the parameter range studied, most probably due to the fact that the inhomogeneous mixing regime could not be fully accessed when phase relaxation times based on global number density are considered.Comment: 17 pages, 10 Postscript figures (figures 3,4,6,7,8 and 10 are in reduced quality), to appear in Theoretical Computational Fluid Dynamic

DAP Kinase-Related Apoptosis-Inducing Protein Kinase 2 (DRAK2) Is a Key Regulator and Molecular Marker in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western World and it is characterized by a marked degree of clinical heterogeneity. An impaired balance between pro- and anti-apoptotic stimuli determines chemorefractoriness and outcome. The low proliferation rate of CLL cells indicates that one of the primary mechanisms involved in disease development may be an apoptotic failure. Here, we study the clinical and functional significance of DRAK2, a novel stress response kinase that plays a critical role in apoptosis, T-cell biology, and B-cell activation in CLL. We have analyzed CLL patient samples and showed that low expression levels of DRAK2 were significantly associated with unfavorable outcome in our CLL cohort. DRAK2 expression levels showed a positive correlation with the expression of DAPK1, and TGFBR1. Consistent with clinical data, the downregulation of DRAK2 in MEC-1 CLL cells strongly increased cell viability and proliferation. Further, our transcriptome data from MEC-1 cells highlighted MAPK, NF-&kappa;B, and Akt and as critical signaling hubs upon DRAK2 knockdown. Taken together, our results indicate DRAK2 as a novel marker of CLL survival that plays key regulatory roles in CLL prognosis

The Rapid Evaluation of COVID-19 Vaccination in Emergency Departments for Underserved Patients Study

Early evidence has suggested a high prevalence of acute pulmonary embolism (PE) in Coronavirus 19 (COVID). However, the bulk of existing data evaluates the population of COVID patients admitted to an intensive care unit (ICU). There has been limited evidence in the emergency department (ED) population and as a result, there is variability in diagnostic evaluation for patients presenting with COVID. The objective of this study was to describe the diagnostic evaluation of both COVID positive and negative patients in the ED

Characterisation of the genomic landscape of CRLF2-rearranged acute lymphoblastic leukemia

Deregulated expression of the type I cytokine receptor, CRLF2, is observed in 5–15% of precursor B-cell acute lymphoblastic leukaemia (B-ALL). We aimed to determine the clinical and genetic landscape of those with IGH-CRLF2 or P2RY8-CRLF2 (CRLF2-r) using multiple genomic approaches. Clinical and demographic features of CRLF2-r patients were characteristic of B-ALL. Patients with IGH-CRLF2 were older (14 y vs. 4 y, P < .001), while the incidence of CRLF2-r among Down syndrome patients was high (50/161, 31%). CRLF2-r co-occurred with primary chromosomal rearrangements but the majority (111/161, 69%) had B-other ALL. Copy number alteration (CNA) profiles were similar to B-other ALL, although CRLF2-r patients harbored higher frequencies of IKZF1 (60/138, 43% vs. 77/1351, 24%) and BTG1 deletions (20/138, 15% vs. 3/1351, 1%). There were significant differences in CNA profiles between IGH-CRLF2 and P2RY8-CRLF2 patients: IKZF1 (25/35, 71% vs. 36/108, 33%, P < .001), BTG1 (11/35, 31% vs. 10/108, 9%, P =.004), and ADD3 deletions (9/19, 47% vs. 5/38, 13%, P =.008). A novel gene fusion, USP9X-DDX3X, was discovered in 10/54 (19%) of patients. Pathway analysis of the mutational profile revealed novel involvement for focal adhesion. Although the functional relevance of many of these abnormalities are unknown, they likely activate additional pathways, which may represent novel therapeutic targets

A comparison between grid and particle methods on the statistics of driven, supersonic, isothermal turbulence

We compare the statistics of driven, supersonic turbulence at high Mach number using FLASH a widely used Eulerian grid-based code and PHANTOM, a Lagrangian SPH code at resolutions of up to 512^3 in both grid cells and SPH particles. We find excellent agreement between codes on the basic statistical properties: a slope of k^-1.95 in the velocity power spectrum for hydrodynamic, Mach 10 turbulence, evidence in both codes for a Kolmogorov-like slope of k^-5/3 in the variable rho^1/3 v as suggested by Kritsuk et al. and a log-normal PDF with a width that scales with Mach number and proportionality constant b=0.33-0.5 in the density variance-Mach number relation. The measured structure function slopes are not converged in either code at 512^3 elements. We find that, for measuring volumetric statistics such as the power spectrum slope and structure function scaling, SPH and grid codes give roughly comparable results when the number of SPH particles is approximately equal to the number of grid cells. In particular, to accurately measure the power spectrum slope in the inertial range, in the absence of subgrid models, requires at least 512^3 computational elements in either code. On the other hand the SPH code was found to be better at resolving dense structures, giving max. densities at a resolution of 128^3 particles that were similar those resolved in the grid code at 512^3 cells, reflected also in the high density tail of the PDF. We find SPH to be more dissipative at comparable numbers of computational elements in statistics of the velocity field, but correspondingly less dissipative than the grid code in the statistics of density weighted quantities such as rho^1/3 v. For SPH simulations of high Mach number turbulence we find it important to use sufficient non-linear beta-viscosity to prevent particle interpenetration in shocks (we require beta=4 instead of the default beta=2).Comment: 16 pages, 15 figures, accepted to MNRAS. Associated movies, images and full res version at: http://users.monash.edu.au/~dprice/pubs/turbulence/index.html v2: minor changes, couple of refs added to match published versio

Low BACH2 Expression Predicts Adverse Outcome in Chronic Lymphocytic Leukaemia

Chronic lymphocytic leukaemia (CLL) is a heterogeneous disease with a highly variable clinical outcome. There are well‐established CLL prognostic biomarkers that have transformed treatment and improved the understanding of CLL biology. Here, we have studied the clinical significance of two crucial B cell regulators, BACH2 (BTB and CNC homology 1, basic leucine zipper transcription factor 2) and BCL6 (B‐cell CLL/lymphoma 6), in a cohort of 102 CLL patients and determined the protein interaction networks that they participate in using MEC‐1 CLL cells. We observed that CLL patients expressing low levels of BCL6 and BACH2 RNA had significantly shorter overall survival (OS) than high BCL6‐ and BACH2‐expressing cases. Notably, their low expression specifically decreased the OS of immunoglobulin heavy chain variable region‐mutated (IGHV‐M) CLL patients, as well as those with 11q and 13q deletions. Similar to the RNA data, a low BACH2 protein expression was associated with a significantly shorter OS than a high expression. There was no direct interaction observed between BACH2 and BCL6 in MEC‐1 CLL cells, but they shared protein networks that included fifty different proteins. Interestingly, a prognostic index (PI) model that we generated, using integrative risk score values of BACH2 RNA expression, age, and 17p deletion status, predicted patient outcomes in our cohort. Taken together, these data have shown for the first time a possible prognostic role for BACH2 in CLL and have revealed protein interaction networks shared by BCL6 and BACH2, indicating a significant role for BACH2 and BCL6 in key cellular processes, including ubiquitination mediated B‐cell receptor functions, nucleic acid metabolism, protein degradation, and homeostasis in CLL biology