Martian carbon dioxide: Clues from isotopes in SNC meteorites

Attempts to unravel the origin and evolution of the atmosphere and hydrosphere on Mars from isotopic data have been hampered by the impreciseness of the measurements made by the Viking Lander and by Earth-based telescopes. The SNC meteorites which are possibly pieces of the Martian surface offer a unique opportunity to obtain more precise estimates of the planet's volatile inventory and isotopic composition. Recently, we reported results on oxygen isotopes of water extracted by pyrolysis from samples of Shergotty, Zagami, Nakhla, Chassigny, Lafayette, and EETA-79001. Now we describe complementary results on the stable isotopic composition of carbon dioxide extracted simultaneously from those same samples. We will also report on C-14 abundances obtained by accelerator mass spectrometry (AMS) for some of these CO2 samples

Gender, media, and mixed martial arts in Poland: the case of Joanna Jędrzejczyk

Recent growth in the media visibility of female combat sport athletes has offered a compelling site for research on gender and sport media, as women in deeply masculinized sports have been increasingly placed in the public spotlight. While scholars in the Anglophone West have offered analyses of the media framing of this phenomenon, little work has been done outside these cultural contexts. Thus, in this paper we offer a qualitative exploration of how Joanna Jędrzejczyk, a Polish champion of the Ultimate Fighting Championship, has been represented in Polish media. Our findings reveal a relatively de-gendered, widely celebratory account, primarily framed by nationalistic discourse–findings we ascribe to both the particularities of the sport of mixed martial arts as well as the historic nature of Jędrzejczyk’s success

Regional Seismic Discrimination Optimization With and Without Nuclear Test Data: Western U.S. Examples

The western U.S. has abundant natural seismicity, historic nuclear explosion data, and widespread mine blasts, making it a good testing ground to study the performance of regional source-type discrimination techniques. We have assembled and measured a large set of these events to systematically explore how to best optimize discrimination performance. Nuclear explosions can be discriminated from a background of earthquakes using regional phase (Pn, Pg, Sn, Lg) amplitude measures such as high frequency P/S ratios. The discrimination performance is improved if the amplitudes can be corrected for source size and path length effects. We show good results are achieved using earthquakes alone to calibrate for these effects with the MDAC technique (Walter and Taylor, 2001). We show significant further improvement is then possible by combining multiple MDAC amplitude ratios using an optimized weighting technique such as Linear Discriminant Analysis (LDA). However this requires data or models for both earthquakes and explosions. In many areas of the world regional distance nuclear explosion data is lacking, but mine blast data is available. Mine explosions are often designed to fracture and/or move rock, giving them different frequency and amplitude behavior than contained chemical shots, which seismically look like nuclear tests. Here we explore discrimination performance differences between explosion types, the possible disparity in the optimization parameters that would be chosen if only chemical explosions were available and the corresponding effect of that disparity on nuclear explosion discrimination. There are a variety of additional techniques in the literature also having the potential to improve regional high frequency P/S discrimination. We explore two of these here: three-component averaging and maximum phase amplitude measures. Typical discrimination studies use only the vertical component measures and for some historic regional nuclear records these are all that are available. However S-waves are often better recorded on the horizontal components and some studies have shown that using a three-component average or a vertical-P/horizontal-S or other three-component measure can improve discrimination over using the vertical alone (e.g. Kim et al. 1997; Bowers et al 2001). Here we compare the performance of vertical and three-component measures on the western U. S. test set. A complication in regional discrimination is the variation in P and S-wave propagation with region. The dominantly observed regional high frequency S-wave can vary with path between Sn and Lg in a spatially complex way. Since the relative lack of high frequency S-waves is the signature of an explosion, failing to account for this could lead to misidentifying an earthquake as an explosion. The regional P phases Pn and Pg vary similarly with path and also with distance, with Pg sometimes being a strong phase at near regional distances but not far regional. One way to try and handle these issues is to correct for all four regional phases but choose the phase with the maximum amplitude. A variation on this strategy is to always use Pn but choose the maximum S phase (e.g. Bottone et al. 2002). Here we compare the discrimination performance of several different (max P)/(max S) measures to vertical, three-component and multivariate measures. Our preliminary results show that multivariate measures perform much better than single ratios, though transportability of the LDA weights between regions is an issue. Also in our preliminary results, we do not find large discrimination performance improvements with three-component averages and maximum phase amplitude measures compared to using the vertical component alone

"It is what it is": masculinity, homosexuality, and inclusive discourse in mixed martial arts

In this paper we make use of inclusive masculinity theory to explore online media representations of male homosexuality and masculinity within the increasingly popular combat sport of mixed martial arts MMA). Adopting a case-study approach, we discuss narratives constructed around one aspirational male MMA fighter, Dakota Cochrane, whose history of having participated in gay pornography became a major talking point on a number of MMA 'fanzine'/'community' websites during early 2012. While these narratives attempted to discursively 'rescue' Cochrane's supposedly threatened masculinity, highlighting both his 'true' heterosexuality and his prodigious fighting abilities, they also simultaneously celebrated the acceptance of homosexual men within the sport which Cochrane's case implied. Thus, we suggest that these media representations of homosexuality and masculinity within MMA are indicative of declining cultural homophobia and homohysteria, and an inclusive vision of masculinity, as previously described by proponents of inclusive masculinity theory

Deletion of the N-terminus of SF2/ASF Permits RS-Domain-Independent Pre-mRNA Splicing

Serine/arginine-rich (SR) proteins are essential splicing factors with one or two RNA-recognition motifs (RRMs) and a C-terminal arginine- and serine-rich (RS) domain. SR proteins bind to exonic splicing enhancers via their RRM(s), and from this position are thought to promote splicing by antagonizing splicing silencers, recruiting other components of the splicing machinery through RS-RS domain interactions, and/or promoting RNA base-pairing through their RS domains. An RS domain tethered at an exonic splicing enhancer can function as a splicing activator, and RS domains play prominent roles in current models of SR protein functions. However, we previously reported that the RS domain of the SR protein SF2/ASF is dispensable for in vitro splicing of some pre-mRNAs. We have now extended these findings via the identification of a short inhibitory domain at the SF2/ASF N-terminus; deletion of this segment permits splicing in the absence of this SR protein's RS domain of an IgM pre-mRNA substrate previously classified as RS-domain-dependent. Deletion of the N-terminal inhibitory domain increases the splicing activity of SF2/ASF lacking its RS domain, and enhances its ability to bind pre-mRNA. Splicing of the IgM pre-mRNA in S100 complementation with SF2/ASF lacking its RS domain still requires an exonic splicing enhancer, suggesting that an SR protein RS domain is not always required for ESE-dependent splicing activation. Our data provide additional evidence that the SF2/ASF RS domain is not strictly required for constitutive splicing in vitro, contrary to prevailing models for how the domains of SR proteins function to promote splicing

Structural basis for terminal loop recognition and stimulation of pri-miRNA-18a processing by hnRNP A1

International audiencePost-transcriptional mechanisms play a predominant role in the control of microRNA (miRNA) production. Recognition of the terminal loop of precursor miRNAs by RNA-binding proteins (RBPs) influences their processing; however, the mechanistic basis for how levels of individual or subsets of miRNAs are regulated is mostly unexplored. We previously showed that hnRNP A1, an RBP implicated in many aspects of RNA processing, acts as an auxiliary factor that promotes the Microprocessor-mediated processing of pri-mir-18a. Here, by using an integrative structural biology approach, we show that hnRNP A1 forms a 1:1 complex with pri-mir-18a where both RNA recognition motifs (RRMs) bind to cognate RNA sequence motifs in the terminal loop of pri-mir-18a. Terminal loop binding induces an allosteric destabilization of base-pairing in the pri-mir-18a stem that promotes its downstream processing. Our results highlight terminal loop RNA recognition by RBPs as a potential general principle of miRNA biogenesis and regulation

Western men and Eastern arts: The significance of Eastern martial arts disciplines in British men's narratives of masculinity

Previous Western sociological research on Eastern martial arts has identified a tension between ‘traditional’ Eastern forms of practice and ‘modernized’ Western methods of training and competition. In particular, the ‘sportization’ of Eastern styles, where combat-centred arts based upon moral philosophies have transformed more or less into competitive activities following Western models of rationalized sport, has been an important theme. However, it is also suggested that Eastern martial arts hold special significance in the West for their seemingly esoteric nature. In this regard, such martial arts are considered significant because they are not ‘sports’, but rather disciplines, with fairly different connotations for practitioners. Drawing on interview data, this paper explores how Western practitioners of Eastern martial arts articulate this difference, principally by examining the place of martial artistry in British men's narratives of masculinity. Comparing themselves favourably to assumed, typical visions of Western sporting masculinity, such men draw upon the imagined uniqueness of their martial arts to construct a sense of moral superiority over other men. In so doing, they contribute to a rejection of what they believe to be ‘mainstream’ sporting Western masculinity, thus indicating the role that ‘alternative’ visions of physical culture can play in men's active constructions of gender

Eye Development under the control of SRp55/B52-Mediated Alternative Splicing of eyeless

The genetic programs specifying eye development are highly conserved during evolution and involve the vertebrate Pax-6 gene and its Drosophila melanogaster homolog eyeless (ey). Here we report that the SR protein B52/SRp55 controls a novel developmentally regulated splicing event of eyeless that is crucial for eye growth and specification in Drosophila. B52/SRp55 generates two isoforms of eyeless differing by an alternative exon encoding a 60-amino-acid insert at the beginning of the paired domain. The long isoform has impaired ability to trigger formation of ectopic eyes and to bind efficiently Eyeless target DNA sequences in vitro. When over-produced in the eye imaginal disc, this isoform induces a small eye phenotype, whereas the isoform lacking the alternative exon triggers eye over-growth and strong disorganization. Our results suggest that B52/SRp55 splicing activity is used during normal eye development to control eye organogenesis and size through regulation of eyeless alternative splicing

A New Integrated Variable Based on Thermometry, Actimetry and Body Position (TAP) to Evaluate Circadian System Status in Humans

The disruption of the circadian system in humans has been associated with the development of chronic illnesses and the worsening of pre-existing pathologies. Therefore, the assessment of human circadian system function under free living conditions using non-invasive techniques needs further research. Traditionally, overt rhythms such as activity and body temperature have been analyzed separately; however, a comprehensive index could reduce individual recording artifacts. Thus, a new variable (TAP), based on the integrated analysis of three simultaneous recordings: skin wrist temperature (T), motor activity (A) and body position (P) has been developed. Furthermore, we also tested the reliability of a single numerical index, the Circadian Function Index (CFI), to determine the circadian robustness. An actimeter and a temperature sensor were placed on the arm and wrist of the non-dominant hand, respectively, of 49 healthy young volunteers for a period of one week. T, A and P values were normalized for each subject. A non-parametric analysis was applied to both TAP and the separate variables to calculate their interdaily stability, intradaily variability and relative amplitude, and these values were then used for the CFI calculation. Modeling analyses were performed in order to determine TAP and CFI reliability. Each variable (T, A, P or TAP) was independently correlated with rest-activity logs kept by the volunteers. The highest correlation (r = −0.993, p<0.0001), along with highest specificity (0.870), sensitivity (0.740) and accuracy (0.904), were obtained when rest-activity records were compared to TAP. Furthermore, the CFI proved to be very sensitive to changes in circadian robustness. Our results demonstrate that the integrated TAP variable and the CFI calculation are powerful methods to assess circadian system status, improving sensitivity, specificity and accuracy in differentiating activity from rest over the analysis of wrist temperature, body position or activity alone