A Sub-Neptune-sized Planet Transiting the M2.5 Dwarf G 9-40: Validation with the Habitable-zone Planet Finder

We validate the discovery of a 2-Earth-radii sub-Neptune-sized planet around the nearby high-proper-motion M2.5 dwarf G 9-40 (EPIC 212048748), using high-precision, near-infrared (NIR) radial velocity (RV) observations with the Habitable-zone Planet Finder (HPF), precision diffuser-assisted ground-based photometry with a custom narrowband photometric filter, and adaptive optics imaging. At a distance of d = 27.9 pc, G 9-40b is the second-closest transiting planet discovered by K2 to date. The planet's large transit depth (~3500 ppm), combined with the proximity and brightness of the host star at NIR wavelengths (J = 10, K = 9.2), makes G 9-40b one of the most favorable sub-Neptune-sized planets orbiting an M dwarf for transmission spectroscopy with James Webb Space Telescope, ARIEL, and the upcoming Extremely Large Telescopes. The star is relatively inactive with a rotation period of ~29 days determined from the K2 photometry. To estimate spectroscopic stellar parameters, we describe our implementation of an empirical spectral-matching algorithm using the high-resolution NIR HPF spectra. Using this algorithm, we obtain an effective temperature of T_(eff) = 3404±73K, and metallicity of [Fe/H] = −0.08±0.13. Our RVs, when coupled with the orbital parameters derived from the transit photometry, exclude planet masses above 11.7M⊕ with 99.7% confidence assuming a circular orbit. From its radius, we predict a mass of M = 5.0^(+3.8)_(−1.9) M⊕ and an RV semiamplitude of K = 4.1^(+3.1)_(−1.6) ms⁻¹, making its mass measurable with current RV facilities. We urge further RV follow-up observations to precisely measure its mass, to enable precise transmission spectroscopic measurements in the future

Science and the Large Hadron Collider: a probe into instrumentation, periodization and classification

On September 19, 2008, the Large Hadron Collider (LHC) at CERN, Switzerland, began the world’s highest energy experiments as a probe into the structure of matter and forces of nature. Just nine days after the gala start-up, an explosion occurred in the LHC tunnel that brought the epic collider to a complete standstill. In light of the catastrophic incident that disrupted the operation of the LHC, the paper investigates the relation of temporality to the cycle of work in science, and raises the question: What kind of methodological value should we ascribe to events such as crises or breakdowns? Drawing upon and integrating classical anthropological themes with two and a half years of fieldwork at the LHC particle accelerator complex, the paper explores how the incident in September, which affected the instrument, acquaints us with the distribution of work in the laboratory. The incident discloses that the organization of science is not a homogenous ensemble, but marked by an enormous diversity of tasks and personnel, at the heart of which lies the opposition of theory and practice, or pure and applied. This opposition not only forms the source and sanction of the intricate division of labor found in high-energy physics, but also provides a satisfactory answer to every question involving the interface of experimental science and engineering skill

Learning Domain-Specific Word Embeddings from Sparse Cybersecurity Texts

Word embedding is a Natural Language Processing (NLP) technique that automatically maps words from a vocabulary to vectors of real numbers in an embedding space. It has been widely used in recent years to boost the performance of a vari-ety of NLP tasks such as Named Entity Recognition, Syntac-tic Parsing and Sentiment Analysis. Classic word embedding methods such as Word2Vec and GloVe work well when they are given a large text corpus. When the input texts are sparse as in many specialized domains (e.g., cybersecurity), these methods often fail to produce high-quality vectors. In this pa-per, we describe a novel method to train domain-specificword embeddings from sparse texts. In addition to domain texts, our method also leverages diverse types of domain knowledge such as domain vocabulary and semantic relations. Specifi-cally, we first propose a general framework to encode diverse types of domain knowledge as text annotations. Then we de-velop a novel Word Annotation Embedding (WAE) algorithm to incorporate diverse types of text annotations in word em-bedding. We have evaluated our method on two cybersecurity text corpora: a malware description corpus and a Common Vulnerability and Exposure (CVE) corpus. Our evaluation re-sults have demonstrated the effectiveness of our method in learning domain-specific word embeddings

Molecular Mechanisms Involved In Inflammatory Angiogenesis Induced By Monocyte Chemotactic Protein Induced Protein-1 (mcpip1)

Major diseases such as cardiovascular diseases, diabetes, obesity and tumor growth are known to involve inflammatory angiogenesis. MCP-induced protein 1 (MCPIP1) encoded by ZC3H12A gene, was reported to promote angiogenesis and is addressed in my dissertation as MCPIP. The mechanism/s involved in the angiogenic differentiation induced by MCPIP was however unknown. The aim of this study was to bridge this gap in our knowledge and delineate the molecular mechanisms and sequential processes involved in angiogenesis mediated via MCPIP. To determine if angiogenesis induced by inflammatory cytokines, TNF-, IL-1 and IL-8 is mediated via induction of MCPIP, knockdown of MCPIP by its specific siRNA, in human umbilical vein endothelial cells was performed. Oxidative stress, ER stress and autophagy are known to be involved in mediating inflammation. We hypothesized that MCPIP-induced angiogenic differentiation is mediated via induction of oxidative stress, ER stress and autophagy. Chemical inhibitors and specific gene knockdown approach were used to inhibit each process postulated. Oxidative stress was inhibited by apocynin or cerium oxide nanoparticles or knockdown of NADPH oxidase subunit, phox47. Endoplasmic reticulum (ER) stress was blocked by tauroursodeoxycholate or knockdown of ER stress signaling protein IRE-1 and autophagy was inhibited by the use of 3methyl adenine, or LY 294002 or by specific knockdown of beclin1. Matrigel assay was used as an in vitro tool to assay angiogenic differentiation. Inhibition of each step inhibited the subsequent steps postulated. The results reveal that angiogenesis induced by inflammatory agents is mediated via sequential induction of MCPIP that causes v oxidative and nitrosative stress resulting in ER stress leading to autophagy required for angiogenesis. MCPIP has deubiquitinase and anti-dicer RNase activities. If and how the dual enzymatic activities of MCPIP mediate angiogenesis was unknown. Our results showed that hypoxia-induced angiogenesis is mediated via MCPIP. MCPIP deubiquitinated ubiquitinated hypoxia-inducible factor (HIF-1) and the stabilized HIF-1 entered the nucleus to promote the transcription of its target genes, cyclooxygenase-2 and vascular endothelial growth factor causing the activation of p38 MAP kinase involved in angiogenesis. MCPIP expression promoted angiogenesis by inhibition of thrombospondin-1 synthesis via induction of silent information regulator (SIRT)-1 and/or via suppression of VEG-inhibitor levels caused by inhibition of NF-B activation. MCPIP inhibited the production of the anti-angiogenic microRNAs (miR)-20b and miR-34a that repress the translation of HIF-1 and SIRT-1, respectively. Cells expressing the RNasedead mutant of MCPIP, D141N, that had lost the ability to induce angiogenesis had deubiquitinase activity but did not inhibit the production of miR-20b and miR-34a. Mimetics of miR-20b and miR-34a inhibited MCPIP-induced angiogenesis. These results show for the first time that both deubiquitinase and anti-dicer RNase activities of MCPIP are involved in inflammatory angiogenesis. Results from our study delineate key processes that could be potential targets for therapeutic intervention against inflammatory angiogenesis

Narrow escape: how ionizing photons escape from disc galaxies

In this paper we calculate the escape fraction ($f_{\rm esc}$) of ionizing photons from starburst galaxies. Using 2-D axisymmetric hydrodynamic simulations, we study superbubbles created by overlapping supernovae in OB associations. We calculate the escape fraction of ionizing photons from the center of the disk along different angles through the superbubble and the gas disk. After convolving with the luminosity function of OB associations, we show that the ionizing photons escape within a cone of $\sim 40 ^\circ$, consistent with observations of nearby galaxies. The evolution of the escape fraction with time shows that it falls initially as cold gas is accumulated in a dense shell. After the shell crosses a few scale heights and fragments, the escape fraction through the polar regions rises again. The angle-averaged escape fraction cannot exceed $\sim [1- \cos (1 \, {\rm radian})] = 0.5$ from geometrical considerations (using the emission cone opening angle). We calculate the dependence of the time- and angle-averaged escape fraction on the mid-plane disk gas density (in the range $n_0=0.15-50$ cm $^{-3}$) and the disk scale height (between $z_0=10-600$ pc). We find that the escape fraction is related to the disk parameters (the mid-plane disk density and scale height) roughly so that $f_{\rm esc}^\alpha n_0^2 z_0^3$ (with $\alpha\approx 2.2$) is a constant. For disks with a given WNM temperature, massive disks have lower escape fraction than low mass galaxies. For Milky Way ISM parameters, we find $f_{\rm esc}\sim 5\%$, and it increases to $\approx 10\%$ for a galaxy ten times less massive. We discuss the possible effects of clumpiness of the ISM on the estimate of the escape fraction and the implications of our results for the reionization of the universe.Comment: accepted for publication in MNRAS, 19 pages, 18 figure

'Modal-noise' in single-mode fibers: A cautionary note for high precision radial velocity instruments

Exploring the use of single-mode fibers (SMFs) in high precision Doppler spectrometers has become increasingly attractive since the advent of diffraction-limited adaptive optics systems on large-aperture telescopes. Spectrometers fed with these fibers can be made significantly smaller than typical 'seeing-limited' instruments, greatly reducing cost and overall complexity. Importantly, classical mode interference and speckle issues associated with multi-mode fibers, also known as 'modal noise', are mitigated when using SMFs, which also provide perfect radial and azimuthal image scrambling. However, these fibers do support multiple polarization modes, an issue that is generally ignored for larger-core fibers given the large number of propagation modes. Since diffraction gratings used in most high resolution astronomical instruments have dispersive properties that are sensitive to incident polarization changes, any birefringence variations in the fiber can cause variations in the efficiency profile, degrading illumination stability. Here we present a cautionary note outlining how the polarization properties of SMFs can affect the radial velocity measurement precision of high resolution spectrographs. This work is immediately relevant to the rapidly expanding field of diffraction-limited, extreme precision RV spectrographs that are currently being designed and built by a number of groups.Comment: 6 pages, 5 figures, accepted for publication in ApJ Letter