bluuebunny/crossref_metadata_2025 huggingface dataset:
An Overview of the Joint Polar Satellite System (JPSS) Science Data Product Calibration and Validation
Authors: Zhou Lihang , Divakarla Murty , Liu Xingpin
Published: February 2016

The Joint Polar Satellite System (JPSS) will launch its first JPSS-1 satellite in early 2017. The JPSS-1 and follow-on satellites will carry aboard an array of instruments including the Visible Infrared Imaging Radiometer Suite (VIIRS), the Cross-track Infrared Sounder (CrIS), the Advanced Technology Microwave Sounder (ATMS), and the Ozone Mapping and Profiler Suite (OMPS). These instruments are similar to the instruments currently operating on the Suomi National Polar-orbiting Partnership (S-NPP) satellite. In preparation for the JPSS-1 launch, the JPSS program at the Center for Satellite Applications and Research (JSTAR) Calibration/Validation (Cal/Val) teams, have laid out the Cal/Val plans to oversee JPSS-1 science products’ algorithm development efforts, verification and characterization of these algorithms during the pre-launch period, calibration and validation of the products during post-launch, and long-term science maintenance (LTSM). In addition, the team has developed the necessary schedules, deliverables and infrastructure for routing JPSS-1 science product algorithms for operational implementation. This paper presents an overview of these efforts. In addition, this paper will provide insight into the processes of both adapting S-NPP science products for JPSS-1 and performing upgrades for enterprise solutions, and will discuss Cal/Val processes and quality assurance procedures.
Design and Analysis of a Single—Camera Omnistereo Sensor for Quadrotor Micro Aerial Vehicles (MAVs)
Authors: Jaramillo Carlos , Valenti Roberto , Guo Ling , Xiao Jizhong
Published: February 2016

We describe the design and 3D sensing performance of an omnidirectional stereo (omnistereo) vision system applied to Micro Aerial Vehicles (MAVs). The proposed omnistereo sensor employs a monocular camera that is co-axially aligned with a pair of hyperboloidal mirrors (a vertically-folded catadioptric configuration). We show that this arrangement provides a compact solution for omnidirectional 3D perception while mounted on top of propeller-based MAVs (not capable of large payloads). The theoretical single viewpoint (SVP) constraint helps us derive analytical solutions for the sensor’s projective geometry and generate SVP-compliant panoramic images to compute 3D information from stereo correspondences (in a truly synchronous fashion). We perform an extensive analysis on various system characteristics such as its size, catadioptric spatial resolution, field-of-view. In addition, we pose a probabilistic model for the uncertainty estimation of 3D information from triangulation of back-projected rays. We validate the projection error of the design using both synthetic and real-life images against ground-truth data. Qualitatively, we show 3D point clouds (dense and sparse) resulting out of a single image captured from a real-life experiment. We expect the reproducibility of our sensor as its model parameters can be optimized to satisfy other catadioptric-based omnistereo vision under different circumstances.
FingerScanner: Embedding a Fingerprint Scanner in a Raspberry Pi
Authors: Sapes Jordi , Solsona Francesc
Published: February 2016

Nowadays, researchers are paying increasing attention to embedding systems. Cost reduction has lead to an increase in the number of platforms supporting the operating system Linux, jointly with the Raspberry Pi motherboard. Thus, embedding devices on Raspberry-Linux systems is a goal in order to make competitive commercial products. This paper presents a low-cost fingerprint recognition system embedded into a Raspberry Pi with Linux.
A Unified Global Reference Frame of Vertical Crustal Movements by Satellite Laser Ranging
Authors: Zhu Xinhui , Wang Ren , Sun Fuping , Wang Jinling
Published: February 2016

Crustal movement is one of the main factors influencing the change of the Earth system, especially in its vertical direction, which affects people’s daily life through the frequent occurrence of earthquakes, geological disasters, and so on. In order to get a better study and application of the vertical crustal movement,as well as its changes, the foundation and prerequisite areto devise and establish its reference frame; especially, a unified global reference frame is required. Since SLR (satellite laser ranging) is one of the most accurate space techniques for monitoring geocentric motion and can directly measure the ground station’s geocentric coordinates and velocities relative to the centre of the Earth’s mass, we proposed to take the vertical velocity of the SLR technique in the ITRF2008 framework as the reference frame of vertical crustal motion, which we defined as the SLR vertical reference frame (SVRF). The systematic bias between other velocity fields and the SVRF was resolved by using the GPS (Global Positioning System) and VLBI (very long baseline interferometry) velocity observations, and the unity of other velocity fields and SVRF was realized,as well. The results show that it is feasible and suitable to take the SVRF as a reference frame, which has both geophysical meanings and geodetic observations, so we recommend taking the SLR vertical velocity under ITRF2008 as the global reference frame of vertical crustal movement.
Sustainability of Social Housing in Asia: A Holistic Multi-Perspective Development Process for Bamboo-Based Construction in the Philippines
Authors: Salzer Corinna , Wallbaum Holger , Lopez Luis , Kouyoumji Jean
Published: February 2016

This paper highlights the need for a more inclusive and sustainable development of social housing in rapidly developing countries of Asia, Latin America, and Africa. At the example of the Philippines, a multi-perspective development process for a bamboo-based building system is developed. Sustainability Assessment Criteria are defined through literature review, field observations and interviews with three stakeholder clusters: (1) Builders and users of traditional bamboo houses in the Philippines; (2) Stakeholders involved in using forest products for housing in other countries around the world; and (3) Stakeholders in the field of social housing in the Philippines. Through coding and sorting of data in a qualitative content analysis, 15 sustainability assessment criteria are identified clustered into the dimensions society, ecology, economy, governance, and technology. Guided by the sustainability criteria and four implementation strategies: (A) Research about and (B) Implementation of the building technology; (C) Participation and Capacity Building of Stakeholders; and (D) Sustainable Supply Chains, a strategic roadmap was created naming, in total, 28 action items. Through segmentation of the complex problem into these action items, the paper identifies one-dimensional methods leading to measurable, quantitative endpoints. In this way, qualitative stakeholder data is translated into quantitative methods, forming a pathway for a holistic assessment of the building technologies. A mid-point, multi-criteria, or pareto decision-making method comparing the 28 endpoints of the alternative to currently practiced conventional solutions is suggested as subject for further research. This framework paper is a contribution to how sustainable building practices can become more inclusive, incorporating the building stock of low-income dwellers. It bridges the gap between theoretical approach and practical applications of sustainability and underlines the strength of combining multi-dimensional development with stakeholder participation.
Overcoming Ex-Post Development Stagnation: Interventions with Continuity and Scaling in Mind
Authors: Hiller Bradley , Guthrie Peter , Jones Aled
Published: February 2016

Project interventions are important vehicles for development globally. However, while there is often allocation of resources for new and innovative (pilot) projects—with varying levels of success—there is seemingly less focus on consolidating and/or scaling the positive impacts of successful larger interventions. Assuming an overarching development goal to have long lasting impact at scale, this approach seems somewhat contradictory. Scaling is often not integrated into project planning, design and implementation and rarely pursued genuinely in the ex-post. However, where demand for further development remains outstanding beyond project completion, opportunities may exist to build upon project platforms and extend benefits in a cost effective manner. This paper examines existing scaling typologies, before introducing “scaling-within” as a concept to promote greater continuity of development to a wider range of stakeholders. Scaling-within offers the opportunity to “in-fill” intervention principles and practices to both project and non-project communities within a broader strategic framework to address disparities and to promote sustainable development. The authors draw on research from case studies of large-scale integrated watershed rehabilitation projects and assess scaling-within against a contemporary scaling framework drawn from the literature. While the concept is tested with watersheds as the administrative unit, the authors anticipate applications for other project management units.
The Development of a Measurement Instrument for the Organizational Performance of Social Enterprises
Authors: Crucke Saskia , Decramer Adelien
Published: February 2016

There is a growing consensus that the adoption of performance measurement tools are of particular interest for social enterprises in order to support internal decision‐making and to answer the demands of accountability toward their stakeholders. As a result, different methodologies to assess the non‐financial performance of social enterprises are developed by academics and practitioners. Many of these methodologies are on the one hand discussions of general guidelines or, on the other hand, very case specific. As such, these methodologies do not offer a functional tool for a broad range of social enterprises. The goal of this article is to fill this gap by developing an instrument suitable for the internal assessment and the external reporting of the non‐financial performance of a diverse group of social enterprises. To reach this goal, we used qualitative (focus groups and a Delphi panel) and quantitative research methods (exploratory and confirmatory factor analysis), involving multiple actors in the field of social entrepreneurship. Focusing on five dimensions of organizational performance (economic, environmental, community, human and governance performance), we offer a set of indicators and an assessment tool for social enterprises.
Accounting Treatment for Carbon Emission Rights
Authors: Gallego-Alvarez Isabel , Martínez-Ferrero Jennifer , Cuadrado-Ballesteros Beatriz
Published: February 2016

In light of the growing demand for sustainable behavior and the special interest that has emerged regarding the social and environmental impact of firms, the purpose of this research is to analyze the determinants of the accounting treatment of emission rights. To achieve that purpose, we use a sample composed of 119 firms worldwide from different countries and activity sectors for the period 2011. Our findings show different accounting treatments depending on a series of factors. Specifically, firms pertaining to countries that have adopted Environmental Trading Schemes (ETS) tend to account for emission rights through provisions, investments, or as inventory. For their part, firms that issue indicators that appear in the report drawn up by KPMG and GRI (2007) tend to account for these entries as expenses, especially as R + D expenses. Finally, firms located in countries that signed the Kyoto protocol have a tendency to not account for carbon emission rights. The findings of this work can be considered of great interest on the international level because our research contributes to the scant previous literature regarding the accounting treatment of emission rights.
Acetylated Deoxynivalenol Generates Differences of Gene Expression that Discriminate Trichothecene Toxicity
Authors: Suzuki Tadahiro , Iwahashi Yumiko
Published: February 2016

Deoxynivalenol (DON), which is a toxic secondary metabolite generated by Fusarium species, is synthesized through two separate acetylation pathways. Both acetylation derivatives, 3-acetyl-DON (3ADON) and 15-acetyl-DON (15ADON), also contaminate grain and corn widely. These derivatives are deacetylated via a variety of processes after ingestion, so it has been suggested that they have the same toxicity as DON. However, in the intestinal entry region such as the duodenum, the derivatives might come into contact with intestinal epithelium cells because metabolism by microflora or import into the body has not progressed. Therefore, the differences of toxicity between DON and these derivatives need to be investigated. Here, we observed gene expression changes in the yeast pdr5Δ mutant strain under concentration-dependent mycotoxin exposure conditions. 15ADON exposure induced significant gene expression changes and DON exposure generally had a similar but smaller effect. However, the glucose transporter genes HXT2 and HXT4 showed converse trends. 3ADON also induced a different expression trend in these genes than DON and 15ADON. These differences in gene expression suggest that DON and its derivatives have different effects on cells.
Methodology for Selecting Best Management Practices Integrating Multiple Stakeholders and Criteria. Part 1: Methodology
Authors: Aceves Mauricio , Fuamba Musandji
Published: February 2016

The implementation of stormwater Best Management Practices (BMPs) could help re-establish the natural hydrological cycle of watersheds after urbanization, with each BMP presenting a different performance across a range of criteria (flood prevention, pollutant removal, etc.). Additionally, conflicting views from the relevant stakeholders may arise, resulting in a complex selection process. This paper proposes a methodology for BMP selection based on the application of multi-criteria decision aid (MCDA) methods, integrating multiple stakeholder priorities and BMP combinations. First, in the problem definition, the MCDA methods, relevant criteria and design guidelines are selected. Next, information from the preliminary analysis of the watershed is used to obtain a list of relevant BMPs. The third step comprises the watershed modeling and analysis of the BMP alternatives to obtain performance values across purely objective criteria. Afterwards, a stakeholder analysis based on survey applications is carried out to obtain social performance values and criteria priorities. Then, the MCDA methods are applied to obtain the final BMP rankings. The last step considers the sensitivity analysis and rank comparisons in order to draw the final conclusions and recommendations. Future improvements to the methodology could explore inclusion of multiple objective analysis, and alternative means for obtaining social performance values.
Influences on Adaptive Planning to Reduce Flood Risks among Parishes in South Louisiana
Authors: Paille Mary , Reams Margaret , Argote Jennifer , Lam Nina , Kirby Ryan
Published: February 2016

Residents of south Louisiana face a range of increasing, climate-related flood exposure risks that could be reduced through local floodplain management and hazard mitigation planning. A major incentive for community planning to reduce exposure to flood risks is offered by the Community Rating System (CRS) of the National Flood Insurance Program (NFIP). The NFIP encourages local collective action by offering reduced flood insurance premiums for individual policy holders of communities where suggested risk-reducing measures have been implemented. This preliminary analysis examines the extent to which parishes (counties) in southern Louisiana have implemented the suggested policy actions and identifies key factors that account for variation in the implementation of the measures. More measures implemented results in higher CRS scores. Potential influences on scores include socioeconomic attributes of residents, government capacity, average elevation and past flood events. The results of multiple regression analysis indicate that higher CRS scores are associated most closely with higher median housing values. Furthermore, higher scores are found in parishes with more local municipalities that participate in the CRS program. The number of floods in the last five years and the revenue base of the parish does not appear to influence CRS scores. The results shed light on the conditions under which local adaptive planning to mitigate increasing flood risks is more likely to be implemented and offer insights for program administrators, researchers and community stakeholders.
Mismatch detection in DNA monolayers by atomic force microscopy and electrochemical impedance spectroscopy
Authors: Ngavouka Maryse D Nkoua , Capaldo Pietro , Ambrosetti Elena , Scoles Giacinto , Casalis Loredana , Parisse Pietro
Published: February 2016

Background: DNA hybridization is at the basis of most current technologies for genotyping and sequencing, due to the unique properties of DNA base-pairing that guarantee a high grade of selectivity. Nonetheless the presence of single base mismatches or not perfectly matched sequences can affect the response of the devices and the major challenge is, nowadays, to distinguish a mismatch of a single base and, at the same time, unequivocally differentiate devices read-out of fully and partially matching sequences.

Results: We present here two platforms based on different sensing strategies, to detect mismatched and/or perfectly matched complementary DNA strands hybridization into ssDNA oligonucleotide monolayers. The first platform exploits atomic force microscopy-based nanolithography to create ssDNA nano-arrays on gold surfaces. AFM topography measurements then monitor the variation of height of the nanostructures upon biorecognition and then follow annealing at different temperatures. This strategy allowed us to clearly detect the presence of mismatches. The second strategy exploits the change in capacitance at the interface between an ssDNA-functionalized gold electrode and the solution due to the hybridization process in a miniaturized electrochemical cell. Through electrochemical impedance spectroscopy measurements on extended ssDNA self-assembled monolayers we followed in real-time the variation of capacitance, being able to distinguish, through the difference in hybridization kinetics, not only the presence of single, double or triple mismatches in the complementary sequence, but also the position of the mismatched base pair with respect to the electrode surface.

Conclusion: We demonstrate here two platforms based on different sensing strategies as sensitive and selective tools to discriminate mismatches. Our assays are ready for parallelization and can be used in the detection and quantification of single nucleotide mismatches in microRNAs or in genomic DNA.
Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates
Authors: Edmunds Michael , Raheem Mohammed Abdul , Boutin Rebecca , Tait Katrina , Tam William
Published: February 2016

Palladium-catalyzed ring-opening reactions of C1 substituted 7-oxanorbornadiene derivatives with aryl iodides were investigated. The optimal conditions for this reaction were found to be PdCl2(PPh3)2, ZnCl2, Et3N and Zn in THF. Both steric and electronic factors played a role in the outcome of the reaction as increasing the steric bulk on the bridgehead carbon decreased the yield. These reactions were found to be highly regioselective, giving only one of the two possible regioisomers in all cases. A diverse collection of novel, highly substituted biphenyl derivatives were obtained.
Using the Real-Ear-to-Coupler Difference within the American Academy of Audiology Pediatric Amplification Guideline: Protocols for Applying and Predicting Earmold RECDs
Authors: Moodie Sheila , Pietrobon Jonathan , Rall Eileen , Lindley George , Eiten Leisha , Gordey Dave , Davidson Lisa , Moodie K. Shane , Bagatto Marlene , Haluschak Meredith Magathan , Folkeard Paula , Scollie Susan
Published: February 2016

Background:Real-ear-to-coupler difference (RECD) measurements are used for the purposes of estimating degree and configuration of hearing loss (in dB SPL ear canal) and predicting hearing aid output from coupler-based measures. Accurate measurements of hearing threshold, derivation
of hearing aid fitting targets, and predictions of hearing aid output in the ear canal assume consistent matching of RECD coupling procedure (i.e., foam tip or earmold) with that used during assessment and in verification of the hearing aid fitting. When there is a mismatch between these coupling
procedures, errors are introduced.Purpose:The goal of this study was to quantify the systematic difference in measured RECD values obtained when using a foam tip versus an earmold with various tube lengths. Assuming that systematic errors exist, the second goal was to investigate the
use of a foam tip to earmold correction for the purposes of improving fitting accuracy when mismatched RECD coupling conditions occur (e.g., foam tip at assessment, earmold at verification).Study Sample:Eighteen adults and 17 children (age range: 3‐127 mo) participated in this
study.Data Collection and Analysis:Data were obtained using simulated ears of various volumes and earmold tubing lengths and from patients using their own earmolds. Derived RECD values based on simulated ear measurements were compared with RECD values obtained for adult and pediatric
ears for foam tip and earmold coupling.Results:Results indicate that differences between foam tip and earmold RECDs are consistent across test ears for adults and children which support the development of a correction between foam tip and earmold couplings for RECDs that can be applied
across individuals.Conclusions:The foam tip to earmold correction values developed in this study can be used to provide improved estimations of earmold RECDs. This may support better accuracy in acoustic transforms related to transforming thresholds and/or hearing aid coupler responses
to ear canal sound pressure level for the purposes of fitting behind-the-ear hearing aids.
THE KINEMATICS OF THE NEBULAR SHELLS AROUND LOW MASS PROGENITORS OF PNe WITH LOW METALLICITY*
Authors: Pereyra Margarita , López José Alberto , Richer Michael G.
Published: February 2016

We analyze the internal kinematics of 26 planetary nebulae (PNe) with low metallicity that appear to derive from progenitor stars of the lowest masses, including the halo PN population. Based upon spatially resolved, long-slit, echelle spectroscopy drawn from the San Pedro Mártir Kinematic Catalog of PNe, we characterize the kinematics of these PNe measuring their global expansion velocities based upon the largest sample used to date for this purpose. We find kinematics that follow the trends observed and predicted in other studies, but also find that most of the PNe studied here tend to have expansion velocities less than 20 km s−1 in all of the emission lines considered. The low expansion velocities that we observe in this sample of low metallicity PNe with low mass progenitors are most likely a consequence of a weak central star (CS) wind driving the kinematics of the nebular shell. This study complements previous results that link the expansion velocities of the PN shells with the characteristics of the CS.
KECK/ESI LONG-SLIT SPECTROSCOPY OF SBS 1421+511: A RECOILING QUASAR NUCLEUS IN AN ACTIVE GALAXY PAIR?
Authors: Sun Luming , Zhou Hongyan , Hao Lei , Jiang Peng , Ge Jian , Ji Tuo , Ma Jingzhe , Zhang Shaohua , Shu Xinwen
Published: February 2016

We present Keck/Echellette Spectrograph and Imager long-slit spectroscopy of SBS 1421+511, a system consisting of a quasar at z = 0.276 and an extended source 3″ north of the quasar. The quasar shows a blue-skewed profile of Balmer broad emission lines, which can be well modeled as emissions from a circular disk with a blueshift velocity of ∼1400 km s−1. The blueshift is better interpreted as resulting from a recoiling active black hole than from a super-massive black hole binary, since the line profile almost kept steady for over one decade in the quasar rest frame. Alternative interpretations are possible as well, such as emissions from a bipolar outflow or a circular disk with spiral emissivity perturbations. The extended source shows Seyfert-like narrow-line ratios and a [O iii] luminosity of

, with almost the same redshift as the quasar and a projected distance of 12.5 kpc at the redshift. SBS 1421+511 is thus likely to be an interacting galaxy pair with a dual active galactic nucleus. Alternatively, the quasar companion only appears to be active but not necessarily so: the gas before/in/behind the companion galaxy is illuminated by the quasar as an extended emission-line region is detected at a similar distance in the opposite direction southern to the quasar, which may be generated either by tidal interactions between the galaxy pair or large-scale outflows from the quasar.
SUPPRESSION OF STAR FORMATION IN THE HOSTS OF LOW-EXCITATION RADIO GALAXIES
Authors: Pace Cameron , Salim Samir
Published: February 2016

The feedback from radio-loud active galactic nuclei (R-AGNs) may help maintain low star-formation (SF) rates in their early-type hosts, but the observational evidence for this mechanism has been inconclusive. We study systematic differences of aggregate spectral energy distributions (SEDs) of various subsets of ∼4000 low-redshift R-AGNs from Best & Heckman with respect to (currently) inactive control samples selected to have matching redshift, stellar mass, population age, axis ratio, and environment. Aggregate SEDs, ranging from the ultraviolet (UV) through mid-infrared (mid-IR, 22 μm), were constructed using a Bayesian method that eliminates biases from non-detections in Galaxy Evolution Explorer and Wide-field Infrared Survey Explorer. We study rare high-excitation sources separately from low-excitation ones, which we split by environment and host properties. We find that both the UV and mid-IR emission of non-cluster R-AGNs (80% of sample) are suppressed by ∼0.2 dex relative to that of the control group, especially for moderately massive galaxies (log M
* ≲ 11). The difference disappears for high-mass R-AGNs and for R-AGNs in clusters, where other, non-AGN quenching/maintenance mechanisms may dominate, or where the suppression of SF due to AGNs may persist between active phases of the central engine, perhaps because of the presence of a hot gaseous halo storing AGN energy. High-excitation (high accretion rate) sources, which make up 2% of the R-AGN sample, do not show any evidence of SF suppression (their UV is the same as in controls), but they exhibit a strong mid-IR excess due to AGN dust heating.
INFLUENCE OF THE NONLINEARITY PARAMETER ON THE SOLAR WIND SUB-ION MAGNETIC ENERGY SPECTRUM: FLR–LANDAU FLUID SIMULATIONS
Authors: Sulem P. L. , Passot T. , Laveder D. , Borgogno D.
Published: February 2016

The cascade of kinetic Alfvén waves (KAWs) at sub-ion scales in the solar wind is simulated numerically using a fluid approach that retains ion and electron Landau damping, together with ion finite Larmor radius (FLR) corrections. Assuming initially equal and isotropic ion and electron temperatures, and an ion beta equal to unity, different simulations are performed by varying the propagation direction and the amplitude of KAWs that are randomly driven at a transverse wavenumber k
0 such that

(where d

i
is the proton inertial length), in order to maintain a prescribed level of turbulent fluctuations. The resulting turbulent regimes are characterized by the nonlinearity parameter, defined as the ratio of the characteristic times of Alfvén wave propagation and of the transverse nonlinear dynamics. The corresponding transverse magnetic energy spectra display power laws with exponents spanning a range of values consistent with spacecraft observations. The meandering of the magnetic field lines and the homogenization of ion temperature along these lines are shown to be related to the strength of the turbulence, measured by the nonlinearity parameter. The results are interpreted in terms of a recently proposed phenomenological model where the homogenization process along field lines induced by Landau damping plays a central role.
MONITORING OBSERVATIONS OF THE JUPITER-FAMILY COMET 17P/HOLMES DURING ITS 2014 PERIHELION PASSAGE
Authors: Kwon Yuna Grace , Ishiguro Masateru , Hanayama Hidekazu , Kuroda Daisuke , Honda Satoshi , Takahashi Jun , Kim Yoonyoung , Lee Myung Gyoon , Choi Young-Jun , Kim Myung-Jin , Vaubaillon Jeremie J. , Miyaji Takeshi , Yanagisawa Kenshi , Yoshida Michitoshi , Ohta Kouji , Kawai Nobuyuki , Fukushima Hideo , Watanabe Jun-ichi
Published: February 2016

We performed a monitoring observation of a Jupiter-family comet, 17P/Holmes, during its 2014 perihelion passage to investigate its secular change in activity. The comet has drawn the attention of astronomers since its historic outburst in 2007, and this occasion was its first perihelion passage since then. We analyzed the obtained data using an aperture photometry package and derived the

parameter, a proxy for the dust-production rate. We found that

showed asymmetric properties with respect to the perihelion passage: it increased moderately from 100 cm at the heliocentric distance of r
h = 2.6–3.1 AU to a maximal value of 185 cm at r
h = 2.2 AU (near the perihelion) during the inbound orbit, while dropping rapidly to 35 cm at r
h = 3.2 AU during the outbound orbit. We applied a model for characterizing dust-production rates as a function of r
h and found that the fractional active area of the cometary nucleus had dropped from 20%–40% in 2008–2011 (around the aphelion) to 0.1%–0.3% in 2014–2015 (around the perihelion). This result suggests that a dust mantle would have developed rapidly in only one orbital revolution around the Sun. Although a minor eruption was observed on UT 2015 January 26 at r
h = 3.0 AU, the areas excavated by the 2007 outburst would be covered with a layer of dust (≲10 cm depth) which would be enough to insulate the subsurface ice and to keep the nucleus in a state of low activity.
HOW GALACTIC ENVIRONMENT REGULATES STAR FORMATION
Authors: Meidt Sharon E.
Published: February 2016

In a new simple model I reconcile two contradictory views on the factors that determine the rate at which molecular clouds form stars—internal structure versus external, environmental influences—providing a unified picture for the regulation of star formation in galaxies. In the presence of external pressure, the pressure gradient set up within a self-gravitating turbulent (isothermal) cloud leads to a non-uniform density distribution. Thus the local environment of a cloud influences its internal structure. In the simple equilibrium model, the fraction of gas at high density in the cloud interior is determined simply by the cloud surface density, which is itself inherited from the pressure in the immediate surroundings. This idea is tested using measurements of the properties of local clouds, which are found to show remarkable agreement with the simple equilibrium model. The model also naturally predicts the star formation relation observed on cloud scales and at the same time provides a mapping between this relation and the closer-to-linear molecular star formation relation measured on larger scales in galaxies. The key is that pressure regulates not only the molecular content of the ISM but also the cloud surface density. I provide a straightforward prescription for the pressure regulation of star formation that can be directly implemented in numerical models. Predictions for the dense gas fraction and star formation efficiency measured on large-scales within galaxies are also presented, establishing the basis for a new picture of star formation regulated by galactic environment.
SECONDARY PRODUCTION AS THE ORIGIN OF THE COSMIC-RAY POSITRON EXCESS
Authors: Kruskal M. , Ahlen S. P. , Tarlé G.
Published: February 2016

The Alpha Magnetic Spectrometer has released high-precision data for cosmic rays, and has verified an excess of positrons relative to expectations from cosmic-ray interactions in the interstellar medium. An exciting and well-known possibility for the excess is production of electron–positron pairs by annihilating dark matter particles in the halo of the Galaxy. We have constructed a new scenario for the propagation of cosmic rays, based on the 2000 SMILI results and various other astrophysical observations and measurements in which the positron excess is due to secondary production. The scenario is studied from a simple heuristic perspective, and also within the constraints of a diffusion-reacceleration model using GALPROP. The conclusions of each approach agree with one another, showing that the scenario agrees well with the observed positron flux, without any need for dark matter or other exotic production mechanisms.
CS EMISSION NEAR MIR-BUBBLES
Authors: Watson C. , Devine Kathryn , Quintanar N. , Candelaria T.
Published: February 2016

We survey 44 young stellar objects located near the edges of mid-IR-identified bubbles in CS (1–0) using the Green Bank Telescope. We detect emission in 18 sources, indicating young protostars that are good candidates for being triggered by the expansion of the bubble. We calculate CS column densities and abundances. Three sources show evidence of infall through non-Gaussian line-shapes. Two of these sources are associated with dark clouds and are promising candidates for further exploration of potential triggered star formation. We obtained on-the-fly maps in CS (1–0) of three sources, showing evidence of significant interactions between the sources and the surrounding environment.
THE VLA NASCENT DISK AND MULTIPLICITY SURVEY OF PERSEUS PROTOSTARS (VANDAM). II. MULTIPLICITY OF PROTOSTARS IN THE PERSEUS MOLECULAR CLOUD
Authors: Tobin John J. , Looney Leslie W. , Li Zhi-Yun , Chandler Claire J. , Dunham Michael M. , Segura-Cox Dominique , Sadavoy Sarah I. , Melis Carl , Harris Robert J. , Kratter Kaitlin , Perez Laura
Published: February 2016

We present a multiplicity study of all known protostars (94) in the Perseus molecular cloud from a Karl G. Jansky Very Large Array survey at Ka-band (8 mm and 1 cm) and C-band (4 and 6.6 cm). The observed sample has a bolometric luminosity range between 0.1 L
⊙ and ∼33 L
⊙, with a median of 0.7 L
⊙. This multiplicity study is based on the Ka-band data, having a best resolution of ∼0.″065 (15 au) and separations out to ∼43″ (10,000 au) can be probed. The overall multiplicity fraction (MF) is found to be 0.40 ± 0.06 and the companion star fraction (CSF) is 0.71 ± 0.06. The MF and CSF of the Class 0 protostars are 0.57 ± 0.09 and 1.2 ± 0.2, and the MF and CSF of Class I protostars are both 0.23 ± 0.08. The distribution of companion separations appears bi-modal, with a peak at ∼75 au and another peak at ∼3000 au. Turbulent fragmentation is likely the dominant mechanism on >1000 au scales and disk fragmentation is likely to be the dominant mechanism on <200 au scales. Toward three Class 0 sources we find companions separated by <30 au. These systems have the smallest separations of currently known Class 0 protostellar binary systems. Moreover, these close systems are embedded within larger (50–400 au) structures and may be candidates for ongoing disk fragmentation.
INDUCED SCATTERING LIMITS ON FAST RADIO BURSTS FROM STELLAR CORONAE
Authors: Lyubarsky Yuri , Ostrovska Sofiya
Published: February 2016

The origin of fast radio bursts remains a puzzle. Suggestions have been made that they are produced within the Earth’s atmosphere, in stellar coronae, in other galaxies, or at cosmological distances. If they are extraterrestrial, the implied brightness temperature is very high, and therefore the induced scattering places constraints on possible models. In this paper, constraints are obtained on flares from coronae of nearby stars. It is shown that the radio pulses with the observed power could not be generated if the plasma density within and in the nearest vicinity of the source is as high as is necessary to provide the observed dispersion measure. However, one cannot exclude the possibility that the pulses are generated within a bubble with a very low density and pass through the dense plasma only in the outer corona.
CONSTRAINTS ON THE BINARY COMPANION TO THE SN Ic 1994I PROGENITOR
Authors: Van Dyk Schuyler D. , de Mink Selma E. , Zapartas Emmanouil
Published: February 2016

Core-collapse supernovae (SNe), which mark the deaths of massive stars, are among the most powerful explosions in the universe and are responsible, e.g., for a predominant synthesis of chemical elements in their host galaxies. The majority of massive stars are thought to be born in close binary systems. To date, putative binary companions to the progenitors of SNe may have been detected in only two cases, SNe 1993J and 2011dh. We report on the search for a companion of the progenitor of the Type Ic SN 1994I, long considered to have been the result of binary interaction. Twenty years after explosion, we used the Hubble Space Telescope to observe the SN site in the ultraviolet (F275W and F336W bands), resulting in deep upper limits on the expected companion: F275W > 26.1 mag and F336W > 24.7 mag. These allow us to exclude the presence of a main sequence companion with a mass ≳10 M
⊙. Through comparison with theoretical simulations of possible progenitor populations, we show that the upper limits to a companion detection exclude interacting binaries with semi-conservative (late Case A or early Case B) mass transfer. These limits tend to favor systems with non-conservative, late Case B mass transfer with intermediate initial orbital periods and mass ratios. The most likely mass range for a putative main sequence companion would be ∼5–12 M
⊙, the upper end of which corresponds to the inferred upper detection limit.
QUARK-NOVAE OCCURRING IN MASSIVE BINARIES: A UNIVERSAL ENERGY SOURCE IN SUPERLUMINOUS SUPERNOVAE WITH DOUBLE-PEAKED LIGHT CURVES
Authors: Ouyed Rachid , Leahy Denis , Koning Nico
Published: February 2016

A quark-nova (QN; the sudden transition from a neutron star into a quark star), which occurs in the second common envelope (CE) phase of a massive binary, gives excellent fits to superluminous, hydrogen-poor, supernovae (SLSNe) with double-peaked light curves, including DES13S2cmm, SN 2006oz, and LSQ14bdq (http://www.quarknova.ca/LCGallery.html). In our model, the H envelope of the less massive companion is ejected during the first CE phase, while the QN occurs deep inside the second, He-rich, CE phase after the CE has expanded in size to a radius of a few tens to a few thousands of solar radii; this yields the first peak in our model. The ensuing merging of the quark star with the CO core leads to black hole formation and accretion, explaining the second long-lasting peak. We study a sample of eight SLSNe Ic with double-humped light curves. Our model provides good fits to all of these, with a universal explosive energy of 2 × 1052 erg (which is the kinetic energy of the QN ejecta) for the first hump. The late-time emissions seen in iPTF13ehe and LSQ14bdq are fit with a shock interaction between the outgoing He-rich (i.e., second) CE and the previously ejected H-rich (i.e., first) CE.
OPTICAL AND NEAR-INFRARED OBSERVATIONS OF SN 2013DX ASSOCIATED WITH GRB 130702A
Authors: Toy V. L. , Cenko S. B. , Silverman J. M. , Butler N. R. , Cucchiara A. , Watson A. M. , Bersier D. , Perley D. A. , Margutti R. , Bellm E. , Bloom J. S. , Cao Y. , Capone J. I. , Clubb K. , Corsi A. , De Cia A. , de Diego J. A. , Filippenko A. V. , Fox O. D. , Gal-Yam A. , Gehrels N. , Georgiev L. , González J. J. , Kasliwal M. M. , Kelly P. L. , Kulkarni S. R. , Kutyrev A. S. , Lee W. H. , Prochaska J. X. , Ramirez-Ruiz E. , Richer M. G. , Román-Zúñiga C. , Singer L. , Stern D. , Troja E. , Veilleux S.
Published: February 2016

We present optical and near-infrared (NIR) light curves and optical spectra of SN 2013dx, associated with the nearby (redshift 0.145) gamma-ray burst GRB 130702A. The prompt isotropic gamma-ray energy released from GRB 130702A is measured to be

erg (1 keV to 10 MeV in the rest frame), placing it intermediate between low-luminosity GRBs like GRB 980425/SN 1998bw and the broader cosmological population. We compare the observed

light curves of SN 2013dx to a SN 1998bw template, finding that SN 2013dx evolves ∼20% faster (steeper rise time), with a comparable peak luminosity. Spectroscopically, SN 2013dx resembles other broad-lined SNe Ic, both associated with (SN 2006aj and SN 1998bw) and lacking (SN 1997ef, SN 2007I, and SN 2010ah) gamma-ray emission, with photospheric velocities around peak of ∼ 21,000 km s−1. We construct a quasi-bolometric (

) light curve for SN 2013dx, only the fifth GRB-associated SN with extensive NIR coverage and the third with a bolometric light curve extending beyond

. Together with the measured photospheric velocity, we derive basic explosion parameters using simple analytic models. We infer a 56Ni mass of

, an ejecta mass of

, and a kinetic energy of

erg (statistical uncertainties only), consistent with previous GRB-associated supernovae. When considering the ensemble population of GRB-associated supernovae, we find no correlation between the mass of synthesized 56Ni and high-energy properties, despite clear predictions from numerical simulations that

should correlate with the degree of asymmetry. On the other hand,

clearly correlates with the kinetic energy of the supernova ejecta across a wide range of core-collapse events.
MULTI-WAVELENGTH STUDY OF A DELTA-SPOT. I. A REGION OF VERY STRONG, HORIZONTAL MAGNETIC FIELD
Authors: Jaeggli S. A.
Published: February 2016

Active region NOAA 11035 appeared in 2009 December, early in the new solar activity cycle. This region achieved a delta sunspot (δ spot) configuration when parasitic flux emerged near the rotationally leading magnetic polarity and traveled through the penumbra of the largest sunspot in the group. Both visible and infrared imaging spectropolarimetry of the magnetically sensitive Fe i line pairs at 6302 and 15650 Å show large Zeeman splitting in the penumbra between the parasitic umbra and the main sunspot umbra. The polarized Stokes spectra in the strongest field region display anomalous profiles, and strong blueshifts are seen in an adjacent region. Analysis of the profiles is carried out using a Milne–Eddington inversion code capable of fitting either a single magnetic component with stray light or two independent magnetic components to verify the field strength. The inversion results show that the anomalous profiles cannot be produced by the combination of two profiles with moderate magnetic fields. The largest field strengths are 3500–3800 G in close proximity to blueshifts as strong as 3.8 km s−1. The strong, nearly horizontal magnetic field seen near the polarity inversion line in this region is difficult to understand in the context of a standard model of sunspot magnetohydrostatic equilibrium.
INTRINSIC ELECTROMAGNETIC VARIABILITY IN CELESTIAL OBJECTS CONTAINING RAPIDLY SPINNING BLACK HOLES
Authors: Zhang Fan
Published: February 2016

Analytical studies have raised the concern that a mysterious expulsion of magnetic field lines by a rapidly spinning black hole (dubbed the black hole Meissner effect) would shut down the Blandford–Znajek process and quench the jets of active galactic nuclei and microquasars. This effect is, however, not seen observationally or in numerical simulations. Previous attempts at reconciling the predictions with observations have proposed several mechanisms to evade the Meissner effect. In this paper, we identify a new evasion mechanism and discuss its observational significance. Specifically, we show that the breakdown of stationarity is sufficient to remove the expulsion of the magnetic field at all multipole orders, and that the associated temporal variation is likely turbulent because of the existence of efficient mechanisms for sharing energy across different modes. Such an intrinsic (as opposed to being driven externally by, e.g., changes in the accretion rate) variability of the electromagnetic field can produce the recorded linear correlation between microvariability amplitudes and mean fluxes, help create magnetic randomness and seed sheared magnetic loops in jets, and lead to a better theoretical fit to the X-ray microvariability power spectral density.
TWO MASSIVE WHITE DWARFS FROM NGC 2323 AND THE INITIAL–FINAL MASS RELATION FOR PROGENITORS OF 4–6.5 M⊙*
Authors: Cummings Jeffrey D. , Kalirai Jason S. , Tremblay P.-E. , Ramirez-Ruiz Enrico
Published: February 2016

We observed a sample of 10 white dwarf candidates in the rich open cluster NGC 2323 (M50) with the Keck Low-Resolution Imaging Spectrometer. The spectroscopy shows eight to be DA white dwarfs, with six of these having high signal-to-noise ratio appropriate for our analysis. Two of these white dwarfs are consistent with singly evolved cluster membership, and both are high mass ∼1.07 M
⊙, and give equivalent progenitor masses of 4.69 M
⊙. To supplement these new high-mass white dwarfs and analyze the initial–final mass relation (IFMR), we also looked at 30 white dwarfs from publicly available data that are mostly all high-mass (

M
⊙). These original published data exhibited significant scatter, and to test if this scatter is true or simply the result of systematics, we have uniformly analyzed the white dwarf spectra and have adopted thorough photometric techniques to derive uniform cluster parameters for their parent clusters. The resulting IFMR scatter is significantly reduced, arguing that mass-loss rates are not stochastic in nature and that within the ranges of metallicity and mass analyzed in this work mass loss is not highly sensitive to variations in metallicity. Lastly, when adopting cluster ages based on Y2 isochrones, the slope of the high-mass IFMR remains steep and consistent with that found from intermediate-mass white dwarfs, giving a linear IFMR from progenitor masses between 3 and 6.5 M
⊙. In contrast, when adopting the slightly younger cluster ages based on PARSEC isochrones, the high-mass IFMR has a moderate turnover near an initial mass of 4 M
⊙.
FIRST SEARCH FOR AN X-RAY–OPTICAL REVERBERATION SIGNAL IN AN ULTRALUMINOUS X-RAY SOURCE
Authors: Pasham Dheeraj R. , Strohmayer Tod E. , Cenko S. Bradley , Trippe Margaret L. , Mushotzky Richard F. , Gandhi Poshak
Published: February 2016

Using simultaneous optical (VLT/FORS2) and X-ray (XMM-Newton) data of NGC 5408, we present the first ever attempt to search for a reverberation signal in an ultraluminous X-ray source (NGC 5408 X-1). The idea is similar to active galactic nucleus broad line reverberation mapping where a lag measurement between the X-ray and the optical flux combined with a Keplerian velocity estimate should enable us to weigh the central compact object. We find that although NGC 5408 X-1's X-rays are variable on a timescale of a few hundred seconds (rms of 9.0 ± 0.5%), the optical emission does not show any statistically significant variations. We set a 3σ upper limit on the rms optical variability of 3.3%. The ratio of the X-ray to the optical variability is an indicator of X-ray reprocessing efficiency. In X-ray binaries, this ratio is roughly 5. Assuming a similar ratio for NGC 5408 X-1, the expected rms optical variability is ≈2%, which is still a factor of roughly two lower than what was possible with the VLT observations in this study. We find marginal evidence (3σ) for optical variability on a ∼24 hr timescale. Our results demonstrate that such measurements can be made, but photometric conditions, low sky background levels, and longer simultaneous observations will be required to reach optical variability levels similar to those of X-ray binaries.