Studying stellar binary systems with the Laser Interferometer Space Antenna using Delayed Rejection Markov chain Monte Carlo methods

Bayesian analysis of LISA data sets based on Markov chain Monte Carlo methods has been shown to be a challenging problem, in part due to the complicated structure of the likelihood function consisting of several isolated local maxima that dramatically reduces the efficiency of the sampling techniques. Here we introduce a new fully Markovian algorithm, a Delayed Rejection Metropolis-Hastings Markov chain Monte Carlo method, to efficiently explore these kind of structures and we demonstrate its performance on selected LISA data sets containing a known number of stellar-mass binary signals embedded in Gaussian stationary noise.Comment: 12 pages, 4 figures, accepted in CQG (GWDAW-13 proceedings

Pilot-tone assisted 16-QAM photonic wireless bridge operating at 250 GHz

A photonic wireless bridge operating at a carrier frequency of 250 GHz is proposed and demonstrated. To mitigate the phase noise of the free-running lasers present in such a link, the tone-assisted carrier recovery is used. Compared to the blind phase noise compensation (PNC) algorithm, this technique exhibited penalties of 0.15 dB and 0.46 dB when used with aggregated Lorentzian linewidths of 28 kHz and 359 kHz, respectively, and 20 GBd 16-quadrature amplitude modulation (QAM) signals. The wireless bridge is also demonstrated in a wavelength division multiplexing (WDM) scenario, where 5 optical channels are generated and sent to the Tx remote antenna unit (RAU). In this configuration, the full band from 224 GHz to 294 GHz is used. Finally, a 50 Gbit/s transmission is achieved with the proposed wireless bridge in single channel configuration. The wireless transmission distance is limited to 10 cm due to the low power emitted by the uni-travelling carrier photodiode used in the experiments. However, link budget calculations based on state-of-the-art THz technology show that distances >1000 m can be achieved with this approach.Comment: 13 pages, in Journal of Lightwave Technolog

Defining Components of the ßcatenin Destruction Complex and Exploring Its Regulation and Mechanisms of Action during Development

A subset of signaling pathways play exceptionally important roles in embryonic and post-embryonic development, and mis-regulation of these pathways occurs in most human cancers. One such pathway is the Wnt pathway. The primary mechanism keeping Wnt signaling off in the absence of ligand is regulated proteasomal destruction of the canonical Wnt effector ßcatenin (or its fly homolog Armadillo). A substantial body of evidence indicates that SCF(βTrCP) mediates βcat destruction, however, an essential role for Roc1 has not been demonstrated in this process, as would be predicted. In addition, other E3 ligases have also been proposed to destroy βcat, suggesting that βcat destruction may be regulated differently in different tissues.Here we used cultured Drosophila cells, human colon cancer cells, and Drosophila embryos and larvae to explore the machinery that targets Armadillo for destruction. Using RNAi in Drosophila S2 cells to examine which SCF components are essential for Armadillo destruction, we find that Roc1/Roc1a is essential for regulating Armadillo stability, and that in these cells the only F-box protein playing a detectable role is Slimb. Second, we find that while embryonic and larval Drosophila tissues use the same destruction complex proteins, the response of these tissues to destruction complex inactivation differs, with Armadillo levels more elevated in embryos. We provide evidence consistent with the possibility that this is due to differences in armadillo mRNA levels. Third, we find that there is no correlation between the ability of different APC2 mutant proteins to negatively regulate Armadillo levels, and their recently described function in positively-regulating Wnt signaling. Finally, we demonstrate that APC proteins lacking the N-terminal Armadillo-repeat domain cannot restore Armadillo destruction but retain residual function in negatively-regulating Wnt signaling.We use these data to refine our model for how Wnt signaling is regulated during normal development

Aerosol Chemistry Resolved by Mass Spectrometry: Linking Field Measurements of Cloud Condensation Nuclei Activity to Organic Aerosol Composition

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science & Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.est.6b01675Aerosol hygroscopic properties were linked to its chemical composition by using complementary online mass spectrometric techniques in a comprehensive chemical characterization study at a rural mountaintop station in central Germany in August 2012. In particular, atmospheric pressure chemical ionization mass spectrometry ((−)APCI-MS) provided measurements of organic acids, organosulfates, and nitrooxy-organosulfates in the particle phase at 1 min time resolution. Offline analysis of filter samples enabled us to determine the molecular composition of signals appearing in the online (−)APCI-MS spectra. Aerosol mass spectrometry (AMS) provided quantitative measurements of total submicrometer organics, nitrate, sulfate, and ammonium. Inorganic sulfate measurements were achieved by semionline ion chromatography and were compared to the AMS total sulfate mass. We found that up to 40% of the total sulfate mass fraction can be covalently bonded to organic molecules. This finding is supported by both on- and offline soft ionization techniques, which confirmed the presence of several organosulfates and nitrooxy-organosulfates in the particle phase. The chemical composition analysis was compared to hygroscopicity measurements derived from a cloud condensation nuclei counter. We observed that the hygroscopicity parameter (κ) that is derived from organic mass fractions determined by AMS measurements may overestimate the observed κ up to 0.2 if a high fraction of sulfate is bonded to organic molecules and little photochemical aging is exhibited

Small RNA changes en route to distinct cellular states of induced pluripotency

MicroRNAs (miRNAs) are critical to somatic cell reprogramming into induced pluripotent stem cells (iPSCs), however, exactly how miRNA expression changes support the transition to pluripotency requires further investigation. Here we use a murine secondary reprogramming system to sample cellular trajectories towards iPSCs or a novel pluripotent ‘F-class’ state and perform small RNA sequencing. We detect sweeping changes in an early and a late wave, revealing that distinct miRNA milieus characterize alternate states of pluripotency. miRNA isoform expression is common but surprisingly varies little between cell states. Referencing other omic data sets generated in parallel, we find that miRNA expression is changed through transcriptional and post-transcriptional mechanisms. miRNA transcription is commonly regulated by dynamic histone modification, while DNA methylation/demethylation consolidates these changes at multiple loci. Importantly, our results suggest that a novel subset of distinctly expressed miRNAs supports pluripotency in the F-class state, substituting for miRNAs that serve such roles in iPSCs

A DOCK8-WIP-WASp complex links T cell receptors to the actin cytoskeleton

Wiskott-Aldrich syndrome (WAS) is associated with mutations in the WAS protein (WASp), which plays a critical role in the initiation of T cell receptor–driven (TCR-driven) actin polymerization. The clinical phenotype of WAS includes susceptibility to infection, allergy, autoimmunity, and malignancy and overlaps with the symptoms of dedicator of cytokinesis 8 (DOCK8) deficiency, suggesting that the 2 syndromes share common pathogenic mechanisms. Here, we demonstrated that the WASp-interacting protein (WIP) bridges DOCK8 to WASp and actin in T cells. We determined that the guanine nucleotide exchange factor activity of DOCK8 is essential for the integrity of the subcortical actin cytoskeleton as well as for TCR-driven WASp activation, F-actin assembly, immune synapse formation, actin foci formation, mechanotransduction, T cell transendothelial migration, and homing to lymph nodes, all of which also depend on WASp. These results indicate that DOCK8 and WASp are in the same signaling pathway that links TCRs to the actin cytoskeleton in TCR-driven actin assembly. Further, they provide an explanation for similarities in the clinical phenotypes of WAS and DOCK8 deficiency.United States. Public Health Service (RO1AI114588)United States. Public Health Service (K08AI114968

Radiation Safety in the Treatment of Patients with Thyroid Diseases by Radioiodine 131I: Practice Recommendations of the American Thyroid Association

Background: Radiation safety is an essential component in the treatment of patients with thyroid diseases by 131I. The American Thyroid Association created a task force to develop recommendations that would inform medical professionals about attainment of radiation safety for patients, family members, and the public. The task force was constituted so as to obtain advice, experience, and methods from relevant medical specialties and disciplines. Methods: Reviews of Nuclear Regulatory Commission regulations and International Commission on Radiological Protection recommendations formed the basic structure of recommendations. Members of the task force contributed both ideas and methods that are used at their respective institutions to aid groups responsible for treatments and that instruct patients and caregivers in the attainment of radiation safety. There are insufficient data on long-term outcomes to create evidence-based guidelines. Results: The information was used to compile delineations of radiation safety. Factors and situations that govern implementation of safety practices are cited and discussed. Examples of the development of tables to ascertain the number of hours or days (24-hour cycles) of radiation precaution appropriate for individual patients treated with 131I for hyperthyroidism and thyroid cancer have been provided. Reminders in the form of a checklist are presented to assist in assessing patients while taking into account individual circumstances that would bear on radiation safety. Information is presented to supplement the treating physician's advice to patients and caregivers on precautions to be adopted within and outside the home. Conclusion: Recommendations, complying with Nuclear Regulatory Commission regulations and consistent with guidelines promulgated by the National Council on Radiation Protection and Measurement (NCRP-155), can help physicians and patients maintain radiation safety after treatment with 131I of patients with thyroid diseases. Both treating physicians and patients must be informed if radiation safety, an integral part of therapy with 131I, is to be attained. Based on current regulations and understanding of radiation exposures, recommendations have been made to guide physicians and patients in safe practices after treatment with radioactive iodine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90492/1/thy-2E2010-2E0403.pd

Girls' Activity Levels and Lesson Contexts in Middle School PE: TAAG Baseline

To assess girls' physical activity (PA) in middle school physical education (PE) as it relates to field site, lesson context and location, teacher gender, and class composition