Bimodality in low-luminosity E and S0 galaxies

Stellar population characteristics are presented for a sample of low-luminosity early-type galaxies (LLEs) in order to compare them with their more luminous counterparts. Long-slit spectra of a sample of 10 LLEs were taken with the ESO New Technology Telescope, selected for their low luminosities. Line strengths were measured on the Lick standard system. Lick indices for these LLEs were correlated with velocity dispersion (σ), alongside published data for a variety of Hubble types. The LLEs were found to fall below an extrapolation of the correlation for luminous ellipticals and were consistent with the locations of spiral bulges in plots of line strengths versus σ. Luminosity weighted average ages, metallicities and abundance ratios were estimated from χ2 fitting of 19 Lick indices to predictions from simple stellar population models. The LLEs appear younger than luminous ellipticals and of comparable ages to spiral bulges. These LLEs show a bimodal metallicity distribution, consisting of a low-metallicity group (possibly misclassified dwarf spheroidal galaxies) and a high-metallicity group (similar to spiral bulges). Finally, they have low α-element to iron peak abundance ratios indicative of slow, extended star formation

A Rac1-independent role for P-Rex1 in melanoblasts

No abstract available

Analyzing meteoroid flights using particle filters

Fireball observations from camera networks provide position and time information along the trajectory of a meteoroid that is transiting our atmosphere. The complete dynamical state of the meteoroid at each measured time can be estimated using Bayesian filtering techniques. A particle filter is a novel approach to modeling the uncertainty in meteoroid trajectories and incorporates errors in initial parameters, the dynamical model used, and observed position measurements. Unlike other stochastic approaches, a particle filter does not require predefined values for initial conditions or unobservable trajectory parameters. The Bunburra Rockhole fireball, observed by the Australian Desert Fireball Network (DFN) in 2007, is used to determine the effectiveness of a particle filter for use in fireball trajectory modeling. The final mass is determined to be 2.16 ± 1.33 kg with a final velocity of 6030 ± 216 ms-1, similar to previously calculated values. The full automatability of this approach will allow an unbiased evaluation of all events observed by the DFN and lead to a better understanding of the dynamical state and size frequency distribution of asteroid and cometary debris in the inner solar system. © 2017. The American Astronomical Society. All rights reserved

An RUL-informed approach for life extension of high-value assets

The conventional approaches for life-extension (LE) of industrial assets are largely qualitative and focus only on a few indicators at the end of an asset’s design life. However, an asset may consist of numerous individual components with different useful lives and therefore applying a single LE strategy to every component will not result in an efficient outcome. In recent years, many advanced analytics techniques have been proposed to estimate the remaining useful life (RUL) of the assets equipped with sensor technology. This paper proposes a data-driven model for LE decision-making based on RUL values predicted on a real-time basis during the asset’s operational life. Our proposed LE model is conceptually targeted at the component, unit, or subsystem level; however, an asset-level decision is made by aggregating information across all components. Consequently, LE is viewed and assessed as a series of ongoing activities, albeit carefully orchestrated in a manner similar to operation and maintenance (O&M). The application of the model is demonstrated using the publicly available NASA C-MAPSS dataset for large commercial turbofan engines. This approach will be very beneficial to asset owners and maintenance engineers as it seamlessly weaves LE strategies into O&M activities, thus optimizing resources

Coping with the Senior Thesis Seminar: Some Thoughts for Both Students and Professors

Based on our experiences as professor and student. respectively, in. the undergraduate Senior Thesis Seminar, we offer our thoughts on the fundamental issues facing participants in this class. We speak to students about selecting a topic, choosing a supervisor, working with classmates, delivering the oral presentation, and coping with difficulties. We advise on professors helping students select a topic, monitoring student progress, adjusting to different types of students, approaching the oral presentations, interacting with faculty in the presence of students, and injecting themselves into student work. Consideration of these ideas-presented as a series of lessons--should promote more effective learning experiences in this course

Gating-like Motions and Wall Porosity in a DNA Nanopore Scaffold Revealed by Molecular Simulations

Recently developed synthetic membrane pores composed of folded DNA enrich the current range of natural and engineered protein pores and of nonbiogenic channels. Here we report all-atom molecular dynamics simulations of a DNA nanotube (DNT) pore scaffold to gain fundamental insight into its atomic structure, dynamics, and interactions with ions and water. Our multiple simulations of models of DNTs that are composed of a six-duplex bundle lead to a coherent description. The central tube lumen adopts a cylindrical shape while the mouth regions at the two DNT openings undergo gating-like motions which provide a possible molecular explanation of a lower conductance state observed in our previous experimental study on a membrane-spanning version of the DNT (ACS Nano 2015, 9, 1117-26). Similarly, the central nanotube lumen is filled with water and ions characterized by bulk diffusion coefficients while the gating regions exhibit temporal fluctuations in their aqueous volume. We furthermore observe that the porous nature of the walls allows lateral leakage of ions and water. This study will benefit rational design of DNA nanopores of enhanced stability of relevance for sensing applications, of nanodevices with tunable gating properties that mimic gated ion channels, or of nanopores featuring defined permeation behavior

Understanding quit decisions in primary care: a qualitative study of older GPs

This is the final version of the article. Available from the publisher via the DOI in this record.OBJECTIVE: To investigate the reasons behind intentions to quit direct patient care among experienced general practitioners (GPs) aged 50-60 years. DESIGN AND SETTING: Qualitative study based on semistructured interviews with GPs in the South West region of England. Transcribed interviews were analysed thematically. PARTICIPANTS: 23 GPs aged 50-60 years: 3 who had retired from direct patient care before age 60, and 20 who intended to quit direct patient care within the next 5 years. RESULTS: The analysis identified four key themes: early retirement is a viable option for many GPs; GPs have employment options other than undertaking direct patient care; GPs report feeling they are doing an (almost) undoable job; and GPs may have other aspirations that pull them away from practice. Findings from this study confirmed those from earlier research, with high workload, ageing and health, family and domestic life, and organisational change all influencing GPs' decisions about when to retire/quit direct patient care. However, in addition, GPs expressed feelings of insecurity and uncertainty regarding the future of general practice, low morale, and issues regarding accountability (appraisal and revalidation) and governance. Suggestions about how to help retain GPs within the active clinical workforce were offered, covering individual, practice and organisational levels. CONCLUSIONS: This research highlights aspects of the current professional climate for GPs that are having an impact on retirement decisions. Any future changes to policy or practice to help retain experienced GPs will benefit from this informed understanding of GPs' views. Key factors to take into account include: making the GP workload more manageable; managing change sympathetically; paying attention to GPs' own health; improving confidence in the future of general practice; and improving GP morale.This study was funded by the South West Academic Health Science Network (grant number: SWAHSN 4.21.019) and the University of Exeter Medical School

The role of mTOR-mediated signals during haemopoiesis and lineage commitment

The serine/threonine protein kinase mechanistic target of rapamycin (mTOR) has been implicated in the regulation of an array of cellular functions including protein and lipid synthesis, proliferation, cell size and survival. Here, we describe the role of mTOR during haemopoiesis within the context of mTORC1 and mTORC2, the distinct complexes in which it functions. The use of conditional transgenic mouse models specifically targeting individual mTOR signalling components, together with selective inhibitors, have generated a significant body of research emphasising the critical roles played by mTOR, and individual mTOR complexes, in haemopoietic lineage commitment and development. This review will describe the profound role of mTOR in embryogenesis and haemopoiesis, underscoring the importance of mTORC1 at the early stages of haemopoietic cell development, through modulation of stem cell potentiation and self-renewal, and erythroid and B cell lineage commitment. Furthermore, the relatively discrete role of mTORC2 in haemopoiesis will be explored during T cell development and B cell maturation. Collectively, this review aims to highlight the functional diversity of mTOR signalling and underline the importance of this pathway in haemopoiesis

K-Ras and β-catenin mutations cooperate with Fgfr3 mutations in mice to promote tumorigenesis in the skin and lung, but not in the bladder

The human fibroblast growth factor receptor 3 (FGFR3) gene is frequently mutated in superficial urothelial cell carcinoma (UCC). To test the functional significance of FGFR3 activating mutations as a ‘driver’ of UCC, we targeted the expression of mutated Fgfr3 to the murine urothelium using Cre-loxP recombination driven by the uroplakin II promoter. The introduction of the Fgfr3 mutations resulted in no obvious effect on tumorigenesis up to 18 months of age. Furthermore, even when the Fgfr3 mutations were introduced together with K-Ras or β-catenin (Ctnnb1) activating mutations, no urothelial dysplasia or UCC was observed. Interestingly, however, owing to a sporadic ectopic Cre recombinase expression in the skin and lung of these mice, Fgfr3 mutation caused papilloma and promoted lung tumorigenesis in cooperation with K-Ras and β-catenin activation, respectively. These results indicate that activation of FGFR3 can cooperate with other mutations to drive tumorigenesis in a context-dependent manner, and support the hypothesis that activation of FGFR3 signaling contributes to human cancer

Galaxy And Mass Assembly (GAMA) : The mechanisms for quiescent galaxy formation at z<1

© 2016 The Authors. One key problem in astrophysics is understanding how and why galaxies switch off their star formation, building the quiescent population that we observe in the local Universe. From the Galaxy And Mass Assembly and VIsible MultiObject Spectrograph Public Extragalactic Redshift surveys, we use spectroscopic indices to select quiescent and candidate transition galaxies.We identify potentially rapidly transitioning post-starburst (PSB) galaxies and slower transitioning green-valley galaxies. Over the last 8Gyr, the quiescent population has grown more slowly in number density at high masses (M * > 10 11 M ⊙ ) than at intermediate masses (M * > 10 10.6 M ⊙ ). There is evolution in both the PSB and green-valley stellar mass functions, consistent with higher mass galaxies quenching at earlier cosmic times.At intermediatemasses (M * > 10 10.6 M ⊙ ), we find a green-valley transition time-scale of 2.6 Gyr. Alternatively, at z ~ 0.7, the entire growth rate could be explained by fast-quenching PSB galaxies, with a visibility time-scale of 0.5 Gyr. At lower redshift, the number density of PSBs is so low that an unphysically short visibility window would be required for them to contribute significantly to the quiescent population growth. The importance of the fast-quenching route may rapidly diminish at z 10 11 M ⊙ ), there is tension between the large number of candidate transition galaxies compared to the slow growth of the quiescent population. This could be resolved if not all high-mass PSB and green-valley galaxies are transitioning from star forming to quiescent, for example if they rejuvenate out of the quiescent population following the accretion of gas and triggering of star formation, or if they fail to completely quench their star formation