A Legal Perspective on Career Limitations upon Female Astronauts Due to Cosmic Radiation Exposure

Triggered by the contemporary assumption that female astronauts are facing a manifestation of gender-based discrimination regarding career options due to NASA’s strict cosmic radiation exposure limit restrictions, the main purpose of this paper is to analyze the legal perspective of this issue through labor principles of opportunity and health. By recognizing galactic cosmic rays as a special type of radiation exposure naturally occurring within the astronaut’s working environment, it is questioned whether such a severe health threat deserves to be used as a justification for labor discrimination. While examining the legal status of astronauts in labor relations may contribute in realizing the importance of an astronaut’s profession as an individual as well as for the benefit of mankind, the capacities that space agencies, as employers, have in order to fulfill their obligation of eliminating health risks originating from cosmic radiation and solar storms, can be further examined in order to find out if this spaceflight opportunity limitation is just another well hidden demonstration of gender-based discrimination, mainly through the following determinants: 1) Duration of the space mission, and 2) Position of the space object. Also, given the fact that the notion of “outer space labor law” is still nonexistent, this paper additionally emphasizes the need for the establishment of international standards concerning protection against cosmic radiation, in order for astronauts, irrelevant of their nationality, to receive equal health protection measures, as subjects to labor relations

Cohomologically Full Rings

open3siInspired by a question raised by Eisenbud–Mustaţă–Stillman regarding the injectivity of maps from Ext modules to local cohomology modules and the work by the third author with Pham, we introduce a class of rings, which we call cohomologically full rings. This class of rings includes many well-known singularities: Cohen–Macaulay rings, Stanley–Reisner rings, F-pure rings in positive characteristics, and Du Bois singularities in characteristics 0⁠. We prove many basic properties of cohomologically full rings, including their behavior under flat base change. We show that ideals defining these rings satisfy many desirable properties, in particular they have small cohomological and projective dimension. When R is a standard graded algebra over a field of characteristic 0⁠, we show under certain conditions that being cohomologically full is equivalent to the intermediate local cohomology modules being generated in degree 0⁠. Furthermore, we obtain Kodaira-type vanishing and strong bounds on the regularity of cohomologically full graded algebras.embargoed_20201028Dao, Hailong; De Stefani, Alessandro; Ma, LinquanDao, Hailong; De Stefani, Alessandro; Ma, Linqua

Seedling emergence and early growth of Chinese fir under different light levels and seed positions: implications for natural regeneration

Chinese fir, Cunninghamia lanceolata (Lamb.) Hook. (Taxodiaceae), is an evergreen conifer primarily distributed in southern China. This species exhibits very poor natural regeneration, possibly due to low light and a thick litter layer. To improve the understanding of the natural regeneration capacity of Chinese fir, in this study, we conducted a shade house experiment to determine the optimum light requirements and seed positions for seedling emergence and early growth. The experiment involved five light levels (100%, 60%, 40%, 15%, 5% of full sunlight) and four seed positions (1 cm beneath the soil surface without litter, on the soil surface without soil–seed contact, on the soil surface and covered with litter, and 1 cm beneath the soil surface and covered with litter). Seedling emergence was highest at 5%–15% sunlight, whereas seedling height, root length, root mass, stem mass, leaf mass, and total mass were highest at 60% sunlight. For each light level, seed position significantly affected emergence and growth. The above-litter position inhibited seedling emergence and survival, while the below-litter position favored seedling emergence and early growth, particularly under high light levels. Based on these results, to enhance natural regeneration of Chinese fir, we recommend periodical thinning to increase light into the understory after successful seedling emergence. We also recommend sowing seeds deeper into the litter to improve soil contact and moisture conditions

Real-time evaluation of longitudinal peak systolic strain (speckle tracking measurement) in left and right ventricles of athletes

<p>Abstract</p> <p>Background</p> <p>Strain, and particularly Longitudinal Peak Systolic Strain (LPSS), plays a role in investigating the segmental and overall contractility of the heart which is a particularly interesting feature in athletes in whom regular training determines several morphological and functional modifications in both the ventricles, that normally work at different loads. Speckle tracking techniques assess the LPSS of LV and RV from B-mode imaging in real time, with uniform accuracy in all segments, and can verify the possible dissimilar segmental contributions of the two chambers to overall myocardial contraction. The aim of the study is to quantify the LPSS in real time in both the ventricles in order to estimate any possible different deformation properties in them during a systolic period.</p> <p>Methods</p> <p>32 subjects (20 athletes and 18 controls) were submitted to a standard echocardiographic examination at rest and after a Hand Grip (HG) stress. From a four-chamber-view image, the LPSS parameter was measured with Speckle Tracking analysis in the basal and medium-apical segments of the two ventricles, at rest and after HG.</p> <p>Results</p> <p>In both athletes and controls, LPSS values were significantly higher in the RV of athletes (RV LPSS ^{medium-apical}-23.87 ± 4.94; ^{basalfreewall}-25.04 ± 4.12 at rest) and controls (RV LPSS^{medium-apical}-25.21 ± 4.97; ^{basalfreewall}-28.69 ± 4.62 at rest) than in the LV of both (athletes LV LPSS ^{medium-apical}-18.14 ± 4.16; ^{basallateralwall}-16.05 ± 12.32; controls ^{medium-apical}-18.81 ± 2.64; ^{basallateralwall}-19.74 ± 3.84) With the HG test a significant enhancement of the LPSS(with P < .05) in the medium-apical segments of LV and RV was evident, but only in athletes; there was no modification of the standard echo-parameters in either group.</p> <p>Conclusion</p> <p>ST analysis is an easy method for investigating the contractility of the RV through deformation parameters, showing greater involvement of the RV than LV at rest. In athletes only, after isometric stress the two ventricles show particular myocardial deformation properties of the regions around the apex where the curvature of the wall is more marked. The clinical application of this new approach in athletes and normal subjects requires further investigation.</p

Responses of Chinese fir and Schima superba seedlings to light gradients: Implications for the restoration of mixed broadleaf-conifer forests from Chinese fir monocultures

Although Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations are widely grown for timber production in southern China, they have low biodiversity and provide limited ecosystem services. To address this problem, C. lanceolata are increasingly mixed with broadleaf Schima superba Gardn. & Champ. (Theaceae). The success of these mixed plantations relies on introducing each species in the appropriate sequence, which requires understanding how tree species respond to light variations. We therefore compared S. superba and C. lanceolata seedling light tolerance in shaded houses under five light gradients (5%, 15%, 40%, 60%, and 100% sunlight). Our findings showed that S. superba seedlings exhibited greater net height increment (ΔHt), net diameter growth (ΔDia), leaf area, root mass, stem mass, leaf mass, and total mass under low light conditions (15% sunlight). However, as sunlight increased, these growth variables became higher in C. lanceolata seedlings. With more sunlight, both species experienced a drop in height to diameter ratio (HDR), and specific leaf area (SLA), but an elevated root to shoot ratio. Additionally, under the same light levels, S. superba seedlings exhibited greater leaf area and root to shoot ratio than C. lanceolata seedlings. Our results suggested that S. superba might be more suitable for underplanting beneath a heavy canopy due to its shade-tolerant traits. In contrast, C. lanceolata was less shade-tolerant, having an optimum seedling growth under full sunlight. These findings suggest that underplanting S. superba seedlings in C. lanceolata monoculture plantation (i.e., underplanting regeneration approach) could be a better silvicultural alternative than simultaneously planting both seedlings

Cooh-Terminal Truncated Alpha1S Subunits Conduct Current Better than Full-Length Dihydropyridine Receptors

Skeletal muscle dihydropyridine (DHP) receptors function both as voltage-activated Ca2+ channels and as voltage sensors for coupling membrane depolarization to release of Ca2+ from the sarcoplasmic reticulum. In skeletal muscle, the principal or α1S subunit occurs in full-length (∼10% of total) and post-transcriptionally truncated (∼90%) forms, which has raised the possibility that the two functional roles are subserved by DHP receptors comprised of different sized α1S subunits. We tested the functional properties of each form by injecting oocytes with cRNAs coding for full-length (α1S) or truncated (α1SΔC) α subunits. Both translation products were expressed in the membrane, as evidenced by increases in the gating charge (Qmax 80–150 pC). Thus, oocytes provide a robust expression system for the study of gating charge movement in α1S, unencumbered by contributions from other voltage-gated channels or the complexities of the transverse tubules. As in recordings from skeletal muscle, for heterologously expressed channels the peak inward Ba2+ currents were small relative to Qmax. The truncated α1SΔC protein, however, supported much larger ionic currents than the full-length product. These data raise the possibility that DHP receptors containing the more abundant, truncated form of the α1S subunit conduct the majority of the L-type Ca2+ current in skeletal muscle. Our data also suggest that the carboxyl terminus of the α1S subunit modulates the coupling between charge movement and channel opening

Congou tea drinking and oesophageal cancer in South China

The study from a large hospital-based case–control for 1248 cases with oesophageal cancer and the same number of controls in South China showed that Congou, a grade of Chinese black tea, may protect against cancers of the oesophagus and reduce the risk of a combination of alcohol drinking and smoking (especially smoking), regardless of temperature when drinking

Generic Mechanism of Emergence of Amyloid Protofilaments from Disordered Oligomeric aggregates

The presence of oligomeric aggregates, which is often observed during the process of amyloid formation, has recently attracted much attention since it has been associated with neurodegenerative conditions such as Alzheimer's and Parkinson's diseases. We provide a description of a sequence-indepedent mechanism by which polypeptide chains aggregate by forming metastable oligomeric intermediate states prior to converting into fibrillar structures. Our results illustrate how the formation of ordered arrays of hydrogen bonds drives the formation of beta-sheets within the disordered oligomeric aggregates that form early under the effect of hydrophobic forces. Initially individual beta-sheets form with random orientations, which subsequently tend to align into protofilaments as their lengths increases. Our results suggest that amyloid aggregation represents an example of the Ostwald step rule of first order phase transitions by showing that ordered cross-beta structures emerge preferentially from disordered compact dynamical intermediate assemblies.Comment: 14 pages, 4 figure

The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast

The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al