Salt polygons and porous media convection

From fairy circles to patterned ground and columnar joints, natural patterns spontaneously appear in many complex geophysical settings. Here, we investigate the origins of polygonally patterned crusts of salt playa and salt pans. These beautifully regular features, approximately a meter in diameter, are found worldwide and are fundamentally important to the transport of salt and dust in arid regions. We show that they are consistent with the surface expression of buoyancy-driven convection in the porous soil beneath a salt crust. By combining quantitative results from direct field observations, analog experiments, and numerical simulations, we further determine the conditions under which salt polygons should form, as well as how their characteristic size emerges

Testing the performance of state-of-the-art dust emission schemes using DO4Models field data

Within the framework of the Dust Observations for Models (DO4Models) project, the performance of three commonly used dust emission schemes is investigated in this paper using a box model environment. We constrain the model with field data (surface and dust particle properties as well as meteorological parameters) obtained from a dry lake bed with a crusted surface in Botswana during a 3 month period in 2011. Our box model results suggest that all schemes fail to reproduce the observed horizontal dust flux. They overestimate the magnitude of the flux by several orders of magnitude. The discrepancy is much smaller for the vertical dust emission flux, albeit still overestimated by up to an order of magnitude. The key parameter for this mismatch is the surface crusting which limits the availability of erosive material, even at higher wind speeds. The second-most important parameter is the soil size distribution. Direct dust entrainment was inferred to be important for several dust events, which explains the smaller gap between modelled and measured vertical dust fluxes. We conclude that both features, crusted surfaces and direct entrainment, need to be incorporated into dust emission schemes in order to represent the entire spectra of source processes. We also conclude that soil moisture exerts a key control on the threshold shear velocity and hence the emission threshold of dust in the model. In the field, the state of the crust is the controlling mechanism for dust emission. Although the crust is related to the soil moisture content to some extent, we are not as yet able to deduce a robust correlation between state of crust and soil moisture

Lack of Association of Polymorphisms in Homocysteine Metabolism Genes with Pseudoexfoliation Syndrome and Glaucoma

Purpose: To evaluate genes involved in homocysteine metabolism as secondary risk factors for pseudoexfoliation syndrome (PXFS) and the associated glaucoma (PXFG). Methods: One hundred eighty-six unrelated patients with PXFS, including 140 patients with PXFG and 127 unrelated control subjects were recruited from the Massachusetts Eye and Ear Infirmary. All the patients and controls were Caucasian of European ancestry. Seventeen tag SNPs from 5 genes (methylenetetrahydrofolate reductase [MTHFR], methionine synthase [MTR], methionine synthase reductase [MTRR], methylenetetrahydrofolate dehydrogenase [MTHFD1], and cystathionine β-synthase [CBS]) were genotyped. Single-SNP association was analyzed using Fisher’s exact test (unconditional) or logistic regression after conditioning on the effects of age and three LOXL1 SNPs (rs1048661, rs3825942, and rs2165241). Interaction analysis was performed between the homocysteine and LOXL1 SNPs using logistic regression. Haplotype analysis and the set-based test were used to test for association of individual genes. Multiple comparisons were corrected using the Bonferroni method. Results: One SNP (rs8006686) in MTHFD1 showed a nominally significant association with PXFG (p=0.015, OR=2.23). None of the seventeen SNPs tested were significantly associated with PXFS or PXFG after correcting for multiple comparisons (Bonferroni corrected p>0.25). After controlling for the effects of age and three associated LOXL1 SNPs, none of the seventeen tested SNPs were associated with PXFS (p>0.12). No significant interaction effects on PXFS were identified between the homocysteine and LOXL1 SNPs (p>0.06). Haplotype analysis and the set-based test did not find significant association of individual genes with PXFS (p>0.23 and 0.20, respectively). Conclusions: Five genes that are critical components of the homocysteine metabolism pathway were evaluated as secondary factors for PXFS and PXFG. Our results suggest that these genes are not significant risk factors for the development of these conditions

The Fundamental Plane at z=1.27: First Calibration of the Mass Scale of Red Galaxies at Redshifts z>1

We present results on the Fundamental Plane (FP) of early-type galaxies in the cluster RDCS J0848+4453 at z=1.27. Internal velocity dispersions of three K-selected early-type galaxies are determined from deep Keck spectra. Structural parameters are determined from HST NICMOS images. The galaxies show substantial offsets from the FP of the nearby Coma cluster, as expected from passive evolution of their stellar populations. The offsets from the FP can be expressed as offsets in M/L ratio. The M/L ratios of the two most massive galaxies are consistent with an extrapolation of results obtained at z=0.02-0.83. The evolution of early-type galaxies with masses >10^11 M_sun is well described by ln M/L(B) = (-1.06 +- 0.09) z, corresponding to passive evolution of -1.50 +- 0.13 mag at z=1.3. Ignoring selection effects, the best fitting stellar formation redshift is z*=2.6, corresponding to a luminosity weighted age at the epoch of observation of ~2 Gyr. The M/L ratios of these two galaxies are also in excellent agreement with predictions from models that include progenitor bias. The third galaxy is a factor ~10 less massive than the other two, shows strong Balmer absorption lines in its spectrum, and is offset from the Coma Fundamental Plane by 2.9 mag in rest-frame B. Despite their large range in M/L ratios, all three galaxies fall in the ``Extremely Red Object'' (ERO) class with I-H>3 and R-K>5, and our results show that it is hazardous to use simple models for converting luminosity to mass for these objects. Measurements of M/L ratios at high redshift can be considered first steps to empirically disentangle luminosity and mass evolution at the high mass end of the galaxy population, lifting an important degeneracy in the interpretation of evolution of the luminosity function. [SHORTENED]Comment: Accepted for publication in the Astrophysical Journa

Partial or Complete Unloading of Skeletal Muscle Leads to Specific Alterations of Anabolic Signal Transduction

Consequences of disuse atrophy of skeletal muscle observed during spaceflight on astronaut health and performance are a focal point of space research. Decrements of both muscle mass and protein synthesis rates have been observed with exposure to varying muscle loading environments (1G \u3e partial loading \u3e 0G), and most of the reduced muscle mass can be attributed to diminished rates of synthesis. However, specific mechanisms behind unloading-dependent reductions of protein synthesis are not well defined. PURPOSE: To determine whether or not alterations of anabolic signal transduction was responsible for the changes previously observed in fractional synthesis rates with specific gravitational loading paradigms. METHODS: Female BALB/cByJ were normalized by bodyweight and assigned to normal cage ambulation (1G), partial weight bearing suspension titrated to approximately 33% bodyweight (G/3), partial weight bearing titrated to 16% bodyweight (G/6) and full unloading of hind limbs (0G) in specially designed cages. All mice were subjected to that loading environment for 21d prior to tissue harvest, and monitored daily. Immunoblotting of the gastrocnemius (n=23) was carried out to analyze alterations of anabolic signal transduction. Although numerous signaling intermediates were assessed, the focus of this abstract will be on ribosomal protein S6 kinase (p70-S6K). This important protein has served as a marker of protein synthesis signal transduction as well as the anabolic capacity in skeletal muscle. RESULTS: Regardless of loading paradigm, no differences were detected among groups for the activation of p70-S6K (as indicated by the phospho: total protein content). Total protein content, however, was ~27% lower than control in 0G and G/3 (P=0.008) with G/6 not being different from control (P\u3e0.05). CONCLUSION: In combination with previous data (unpublished observations), Partial gravitational fields at least partially rescues anabolic signaling, suggesting that a threshold level of stimulus is necessary to maintain anabolic capacity in muscle. These results may have important implications towards the development of strategies designed to counter the effects of partial/complete unloading on skeletal muscle based on how the anabolic capacity of muscle is affected

Plasma metabolite profile for primary open-angle glaucoma in three US cohorts and the UK Biobank

Glaucoma is a progressive optic neuropathy and a leading cause of irreversible blindness worldwide. Primary open-angle glaucoma is the most common form, and yet the etiology of this multifactorial disease is poorly understood. We aimed to identify plasma metabolites associated with the risk of developing POAG in a case-control study (599 cases and 599 matched controls) nested within the Nurses' Health Studies, and Health Professionals' Follow-Up Study. Plasma metabolites were measured with LC-MS/MS at the Broad Institute (Cambridge, MA, USA); 369 metabolites from 18 metabolite classes passed quality control analyses. For comparison, in a cross-sectional study in the UK Biobank, 168 metabolites were measured in plasma samples from 2,238 prevalent glaucoma cases and 44,723 controls using NMR spectroscopy (Nightingale, Finland; version 2020). Here we show higher levels of diglycerides and triglycerides are adversely associated with glaucoma in all four cohorts, suggesting that they play an important role in glaucoma pathogenesis

Minimal model for aeolian sand dunes

We present a minimal model for the formation and migration of aeolian sand dunes. It combines a perturbative description of the turbulent wind velocity field above the dune with a continuum saltation model that allows for saturation transients in the sand flux. The latter are shown to provide the characteristic length scale. The model can explain the origin of important features of dunes, such as the formation of a slip face, the broken scale invariance, and the existence of a minimum dune size. It also predicts the longitudinal shape and aspect ratio of dunes and heaps, their migration velocity and shape relaxation dynamics. Although the minimal model employs non-local expressions for the wind shear stress as well as for the sand flux, it is simple enough to serve as a very efficient tool for analytical and numerical investigations and to open up the way to simulations of large scale desert topographies.Comment: 19 pages, 22 figure

Children endorse deterrence motivations for third-party punishment but derive higher enjoyment from compensating victims.

Children’s punishment behavior may be driven by both retribution and deterrence, but the potential primacy of either motive is unknown. Moreover, children’s punishment enjoyment and compensation enjoyment have never been directly contrasted. Here, British, Colombian, and Italian 7- to 11-year-old children (N = 123) operated a Justice System in which they viewed different moral transgressions in Minecraft, a globally popular video game, either face-to-face with an experimenter or over the internet. Children could respond to transgressions by punishing transgressors and compensating victims. The purpose of the system was framed in terms of retribution, deterrence, or compensation between participants. Children’s performance, endorsement, and enjoyment of punishment and compensation were measured, along with their endorsement of retribution versus deterrence as punishment justifications, during and/or after justice administration. Children overwhelmingly endorsed deterrence over retribution as their punishment justification irrespective of age. When asked to reproduce the presented frame in their own words, children more reliably reproduced the deterrence frame rather than the retribution frame. Punishment enjoyment decreased while compensation enjoyment increased over time. Despite enjoying compensation more, children preferentially endorsed punishment over compensation, especially with increasing age and transgression severity. Reported deterrent justifications, superior reproduction of deterrence framing, lower enjoyment of punishment than of compensation, and higher endorsement of punishment over compensation together suggest that children felt that they ought to mete out punishment as a means to deter future transgressions. Face-to-face and internet-mediated responses were not distinguishable, supporting a route to social psychology research with primary school-aged children unable to physically visit labs

Plaskett's Star: Analysis of the CoRoT photometric data

The SRa02 of the CoRoT space mission for Asteroseismology was partly devoted to stars belonging to the Mon OB2 association. An intense monitoring was performed on Plaskett's Star (HD47129) and the unprecedented quality of the light curve allows us to shed new light on this very massive, non-eclipsing binary system. We particularly aimed at detecting periodic variability which might be associated with pulsations or interactions between both components. We also searched for variations related to the orbital cycle which could help to constrain the inclination and the morphology of the binary system. A Fourier-based prewhitening and a multiperiodic fitting procedure were applied to analyse the time series and extract the frequencies of variations. We describe the noise properties to tentatively define an appropriate significance criterion, to only point out the peaks at a certain significance level. We also detect the variations related to the orbital motion and study them by using the NIGHTFALL program. The periodogram exhibits a majority of peaks at low frequencies. Among these peaks, we highlight a list of about 43 values, including notably two different sets of harmonic frequencies whose fundamental peaks are located at about 0.07 and 0.82d-1. The former represents the orbital frequency of the binary system whilst the latter could probably be associated with non-radial pulsations. The study of the 0.07d-1 variations reveals the presence of a hot spot most probably situated on the primary star and facing the secondary. The investigation of this unique dataset constitutes a further step in the understanding of Plaskett's Star. These results provide a first basis for future seismic modelling. The existence of a hot region between both components renders the determination of the inclination ambiguous.Comment: Accepted in A&A, 13 pages, 7 figures, 2 table

Feasibility of High-Throughput Genome-Wide Genotyping using DNA from Stored Buccal Cell Samples

It is unclear if buccal cell samples contain sufficient human DNA with adequately sized fragments for high throughput genetic bioassays. Yet buccal cell sample collection is an attractive alternative to gathering blood samples for genetic epidemiologists engaged in large-scale genetic biomarker studies. We assessed the genotyping efficiency (GE) and genotyping concordance (GC) of buccal cell DNA samples compared to corresponding blood DNA samples, from 32 Nurses’ Health Study (NHS) participants using the Illumina Infinium 660W-Quad platform. We also assessed how GE and GC accuracy varied as a function of DNA concentration using serial dilutions of buccal DNA samples. Finally we determined the nature and genomic distribution of discordant genotypes in buccal DNA samples. The mean GE of undiluted buccal cell DNA samples was high (99.32%), as was the GC between the paired buccal and blood samples (99.29%). GC between the dilutions versus the undiluted buccal DNA was also very high (greater than 97%), though both GE and GC notably declined at DNA concentrations less than 5 ng/μl. Most (greater than 95%) genotype determinations in buccal cell samples were of the “missing call” variety (as opposed to the “alternative genotype call” variety) across the spectrum of buccal DNA concentrations studied. Finally, for buccal DNA concentration above 1.7 ng/ul, discordant genotyping calls did not cluster in any particular chromosome. Buccal cell-derived DNA represents a viable alternative to blood DNA for genotyping on a high-density platform