Beagle 2: Seeking the signatures of life on Mars

ESA's Beagle 2 lander will land on Mars to search for signatures of present and past life. A Gas Analysis Package (GAP) with a mass spectrometer, XRF, Mossbauer, stereo cameras, microscope, environmental sensors, rock corer/grinder, and a Mole attachment are on the lander

Timescales of magmatic processes and eruption ages of the Nyiragongo volcanics from 238U-230Th-226Ra-210Pb disequilibria

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 288 (2009): 149-1157, doi:10.1016/j.epsl.2009.09.017.The silica-undersaturated Nyiragongo volcanics, located in the East African rift, have globally unique chemical compositions and unusually low viscosities, only higher than carbonatite lavas, for terrestrial silicate magmas. We report 238U-230Th-226Ra-210Pb series disequilibria in 13 recent and prehistoric lava samples from Nyiragongo including those from the 2002 flank eruption and a 2003 lava lake sample. (230Th/238U) ranges from 0.90- 0.97 in the recent lavas and from 0.94-1.09 in the prehistoric lavas. To explain the variable 230Th and 238U excesses in these lavas, we hypothesize that different processes with opposite effects in terms of fractionating Th/U in the mantle source are involved. These processes include: 1) low degree partial melting of a phlogopite-bearing mantle source (consistent with low K/Rb) with residual garnet (consistent with high chondrite-normalized Dy/Yb), to produce the observed 230Th excesses; and, 2) carbonate metasomatism for the 238U enrichment, consistent with high Zr/Hf in the Nyiragongo lavas. The Nyiragongo volcanics have higher (230Th/232Th) values than observed in most mantle-derived rocks, especially ocean-island basalts, suggesting that their mantle-source was affected by carbonate metasomatism less than 300 ka ago. Several Nyiragongo samples display significant 226Ra excesses implying rapid magma transport (less than 8 ka) from the mantle-source to the surface. Modeling the observed (226Ra/230Th) versus Zr/Hf correlation in the lavas indicates that the 2002, 2003 and a few pre-historic lavas incorporated 50-60% of a carbonate-metasomatized mantle source while the other prehistoric lavas show 10-22% contribution of this source. This result indicates that the Nyiragongo lavas were derived from a heterogeneous, non-uniformly carbonated mantle source. The 2002 lava shows (210Pb/226Ra) equilibrium, whereas the 2003 lava lake sample shows initial (210Pb/226Ra) < 1. The latter observation suggests that Nyiragongo magmas degas as they rise to the surface over years or decades before eruption. (210Pb/226Ra) equilibrium in the 2002 lava suggests that the 2002 magma may have stagnated for more than a decade before eruption. The high CO2 content, high emission rates, extreme fluidity, along with the inferred short residence time and our inferences of rapid magma transport and high eruptive frequency suggest that the volcanic hazards of Nyiragongo, both from lava flows and gas emissions, are higher than previously estimated.Lava samples were collected as a part of a field work in Nyiragongo, supported by UN-OCHA grants. The field team included Paolo Papale, Alba Santo, Dario Tedesco and Orlando Vaselli with support from the staff of Goma Volcanological Observatory, D. R. Congo. The 2003 lava lake sample was collected by Jacques Durieux. Funding for U-series analyses was covered by NSF-EAR 063824101 and NSF-EAR 083887800 to KWWS. 210Po analyses were funded with EAR0738776 to MR. Sample preparation and dissolution was covered by NSF-EAR 0732679 to ARB. RC acknowledges guest student award from WHOI

SARS coronavirus replicase proteins in pathogenesis

Much progress has been made in understanding the role of structural and accessory proteins in the pathogenesis of severe acute respiratory syndrome coronavirus (SARS-CoV) infections. The SARS epidemic also brought new attention to the proteins translated from ORF1a and ORF1b of the input genome RNA, also known as the replicase/transcriptase gene. Evidence for change within the ORF1ab coding sequence during the SARS epidemic, as well as evidence from studies with other coronaviruses, indicates that it is likely that the ORF1ab proteins play roles in virus pathogenesis distinct from or in addition to functions directly involved in viral replication. Recent reverse genetic studies have confirmed that proteins of ORF1ab may be involved in cellular signaling and modification of cellular gene expression, as well as virulence by mechanisms yet to be determined. Thus, the evolution of the ORF1ab proteins may be determined as much by issues of host range and virulence as they are by specific requirements for intracellular replication

Creativity and Autonomy in Swarm Intelligence Systems

This work introduces two swarm intelligence algorithms -- one mimicking the behaviour of one species of ants (\emph{Leptothorax acervorum}) foraging (a `Stochastic Diffusion Search', SDS) and the other algorithm mimicking the behaviour of birds flocking (a `Particle Swarm Optimiser', PSO) -- and outlines a novel integration strategy exploiting the local search properties of the PSO with global SDS behaviour. The resulting hybrid algorithm is used to sketch novel drawings of an input image, exploliting an artistic tension between the local behaviour of the `birds flocking' - as they seek to follow the input sketch - and the global behaviour of the `ants foraging' - as they seek to encourage the flock to explore novel regions of the canvas. The paper concludes by exploring the putative `creativity' of this hybrid swarm system in the philosophical light of the `rhizome' and Deleuze's well known `Orchid and Wasp' metaphor

Considerations in the determination of orientational order parameters from X-ray scattering experiments

An assessment of the data processing and analysis methods used to obtain the second- and fourth-rank orientational order parameters of liquid crystals from X-ray scattering experiments has been carried out, using experimental data from four extensively studied alkyl-cyanobiphenyls and calculated data generated from two general types of theoretical orientational distribution function. The application of a background subtraction and two different baseline correction methods to the scattering profiles is assessed, along with three different methods to analyse the processed data. The choice of baseline correction method is shown to have a significant effect: an offset to zero overestimates the order parameters from the experimental and calculated data sets, particularly for lower order parameters arising from broad distributions, whereas an offset to a value estimated from regions of low scattering intensity provides experimental values close to those reported from other experimental techniques. By contrast, the three different analysis methods are shown generally to result in relatively small absolute differences between the order parameters. We outline a straightforward general approach to experimental X-ray scattering data processing and analysis for uniaxial phases that results in order parameters that match well with those reported using other experimental techniques

Increased autophagy in EphrinB2-deficient osteocytes is associated with elevated secondary mineralization and brittle bone

Mineralized bone forms when collagen-containing osteoid accrues mineral crystals. This is initiated rapidly (primary mineralization), and continues slowly (secondary mineralization) until bone is remodeled. The interconnected osteocyte network within the bone matrix differentiates from bone-forming osteoblasts; although osteoblast differentiation requires EphrinB2, osteocytes retain its expression. Here we report brittle bones in mice with osteocyte-targeted EphrinB2 deletion. This is not caused by low bone mass, but by defective bone material. While osteoid mineralization is initiated at normal rate, mineral accrual is accelerated, indicating that EphrinB2 in osteocytes limits mineral accumulation. No known regulators of mineralization are modified in the brittle cortical bone but a cluster of autophagy-associated genes are dysregulated. EphrinB2-deficient osteocytes displayed more autophagosomes in vivo and in vitro, and EphrinB2-Fc treatment suppresses autophagy in a RhoA-ROCK dependent manner. We conclude that secondary mineralization involves EphrinB2-RhoA-limited autophagy in osteocytes, and disruption leads to a bone fragility independent of bone mass.Mineralized bone forms when collagen-containing osteoid accrues mineral crystals. This is initiated rapidly (primary mineralization), and continues slowly (secondary mineralization) until bone is remodeled. The interconnected osteocyte network within the bone matrix differentiates from bone-forming osteoblasts; although osteoblast differentiation requires EphrinB2, osteocytes retain its expression. Here we report brittle bones in mice with osteocyte-targeted EphrinB2 deletion. This is not caused by low bone mass, but by defective bone material. While osteoid mineralization is initiated at normal rate, mineral accrual is accelerated, indicating that EphrinB2 in osteocytes limits mineral accumulation. No known regulators of mineralization are modified in the brittle cortical bone but a cluster of autophagy-associated genes are dysregulated. EphrinB2-deficient osteocytes displayed more autophagosomes in vivo and in vitro, and EphrinB2-Fc treatment suppresses autophagy in a RhoA-ROCK dependent manner. We conclude that secondary mineralization involves EphrinB2-RhoA-limited autophagy in osteocytes, and disruption leads to a bone fragility independent of bone mass

Electronic submission and the movement towards a paperless law office in a modern university

The Government’s target of 50% of all under 30 year olds studying at higher education institutions by 2010, coupled with the National Committee Inquiry into Higher Education’ (1997) concluding that further expansion of higher education could not be afforded under the existing funding arrangements, may have serious ramifications for higher education in the UK. Alongside this increase in numbers, students are increasingly seen as educational consumers with increased choice in a demand-led market which universities must recognise. To compete in this academic environment these institutions are having to be ever more consumer aware in the services they offer and are having to increase choice to attract customers from rival enterprises. Information technology is playing an increasing role in the learning experience as noted by institutional commentators such as the Higher Education Funding Council for England, the Joint Information Systems Committee, the Electronic Books ON-screen Interface group and Lord Dearing’s Report. Technology’s use is further evidenced through institutions’ employment of the internet, e-mail and web-based learning to harness the power of this medium. This paper focuses on the concept of commercialism in the university sector and how a movement to a paperless office may be one way in which a university could gain an early competitive advantage over its rivals. The paper takes a student perspective to demonstrate whether students would wish to move towards electronic methods of submission of assessed work and considers the current problems that are encountered in physical submission of documents. This is the first paper in an on-going research project investigating the benefits and viability of a paperless law office, and the results demonstrate both that the students desire more flexibility in submission of university work and that their acceptance may be the easy first step on the road to the paperless law school

SER-109: An Oral Investigational Microbiome Therapeutic for Patients with Recurrent Clostridioides difficile Infection (rCDI)

Clostridioides difficile infection (CDI) is classified as an urgent health threat by the Centers for Disease Control and Prevention (CDC), and affects nearly 500,000 Americans annually. Approximately 20–25% of patients with a primary infection experience a recurrence, and the risk of recurrence increases with subsequent episodes to greater than 40%. The leading risk factor for CDI is broad-spectrum antibiotics, which leads to a loss of microbial diversity and impaired colonization resistance. Current FDA-approved CDI treatment strategies target toxin or toxin-producing bacteria, but do not address microbiome disruption, which is key to the pathogenesis of recurrent CDI. Fecal microbiota transplantation (FMT) reduces the risk of recurrent CDI through the restoration of microbial diversity. However, FDA safety alerts describing hospitalizations and deaths related to pathogen transmission have raised safety concerns with the use of unregulated and unstandardized donor-derived products. SER-109 is an investigational oral microbiome therapeutic composed of purified spore-forming Firmicutes. SER-109 was superior to a placebo in reducing CDI recurrence at Week 8 (12% vs. 40%, respectively; p \u3c 0.001) in adults with a history of recurrent CDI with a favorable observed safety profile. Here, we discuss the role of the microbiome in CDI pathogenesis and the clinical development of SER-109, including its rigorous manufacturing process, which mitigates the risk of pathogen transmission. Additionally, we discuss compositional and functional changes in the gastrointestinal microbiome in patients with recurrent CDI following treatment with SER-109 that are critical to a sustained clinical response

Discovery of an intermediate-luminosity red transient in M51 and its likely dust-obscured, infrared-variable progenitor

We present the discovery of an optical transient (OT) in Messier 51, designated M51 OT2019-1 (also ZTF19aadyppr, AT 2019abn, ATLAS19bzl), by the Zwicky Transient Facility (ZTF). The OT rose over 15 days to an observed luminosity of $M_r=-13$ (${\nu}L_{\nu}=9\times10^6~L_{\odot}$), in the luminosity gap between novae and typical supernovae (SNe). Spectra during the outburst show a red continuum, Balmer emission with a velocity width of $\approx400$ km s$^{-1}$, Ca II and [Ca II] emission, and absorption features characteristic of an F-type supergiant. The spectra and multiband light curves are similar to the so-called "SN impostors" and intermediate-luminosity red transients (ILRTs). We directly identify the likely progenitor in archival Spitzer Space Telescope imaging with a $4.5~\mu$m luminosity of $M_{[4.5]}\approx-12.2$ and a $[3.6]-[4.5]$ color redder than 0.74 mag, similar to those of the prototype ILRTs SN 2008S and NGC 300 OT2008-1. Intensive monitoring of M51 with Spitzer further reveals evidence for variability of the progenitor candidate at [4.5] in the years before the OT. The progenitor is not detected in pre-outburst Hubble Space Telescope optical and near-IR images. The optical colors during outburst combined with spectroscopic temperature constraints imply a higher reddening of $E(B-V)\approx0.7$ mag and higher intrinsic luminosity of $M_r\approx-14.9$ (${\nu}L_{\nu}=5.3\times10^7~L_{\odot}$) near peak than seen in previous ILRT candidates. Moreover, the extinction estimate is higher on the rise than on the plateau, suggestive of an extended phase of circumstellar dust destruction. These results, enabled by the early discovery of M51 OT2019-1 and extensive pre-outburst archival coverage, offer new clues about the debated origins of ILRTs and may challenge the hypothesis that they arise from the electron-capture induced collapse of extreme asymptotic giant branch stars.Comment: 21 pages, 5 figures, published in ApJ