bluuebunny/crossref_metadata_2025_split huggingface dataset:
The roles of atomic and molecular gas on the redshift evolution of star formation and metallicity in galaxy formation models
Authors: Fu Jian , Kauffmann Guinevere 
Published: March 2013

AbstractWe study the redshift evolution of neutral and molecular gas in the interstellar medium with the results from semi-analytic models of galaxy formation and evolution, which track the cold gas related physical processes in radially resolved galaxy disks. Two kinds of prescriptions are adopted to describe the conversion between molecular and neutral gas in the ISM: one is related to the gas surface density and gas metallicity based on the model results by Krumholz, Mckee & Tumlinson; the other is related the pressure of ISM. We try four types of star formation laws in the models to study the effect of the molecular gas component and the star formation time scale on the model results, and find that the H2 dependent star formation rate with constant star formation efficiency is the preferred star formation law. We run the models based on both Millennium and Millennium II Simulation haloes, and the model parameters are adjusted to fit the observations at z = 0 from THINGS/HERACLES and ALFALFA/COLD GASS. We give predictions for the redshift evolution of cosmic star formation density, H2 to HI cosmic ratios, gas to star mass ratios and gas metallicity vs stellar mass relation. Based on the model results, we find that: (i) the difference in the H2 to HI ratio at z > 3 between the two H2 fraction prescriptions can help future observations to test which prescription is better; (ii) a constant redshift independent star formation time scale will postpone the star formation processes at high redshift and cause obvious redshift evolution for the relation between gas metallicity and stellar mass in galaxies at z < 3.
A Herschel Spectroscopic Survey of Warm Molecular Gas in Local Infrared Luminous Galaxies
Authors: Lu N. , Zhao Y. , Xu C. K. , Gao Y. ,   the GOALS FTS Team
Published: March 2013

AbstractWe describe an on-going 194-671 μm spectroscopic survey of a flux-limited sample of 125 local luminous infrared galaxies (LIRGs) with Herschel SPIRE Fourier Transform Spectrometer (FTS). The survey targets primarily the CO spectral line energy distribution (SLED), from J = 4-3 up to J = 13-12, to probe dense and warm molecular gas that should play an intimate role in star formation and/or active galactic nuclear activities in these galaxies. The program is about 75% finished. At S/N > 5, besides the CO lines, we also detected [N ii] 205 μm and [C i] 370 μm (3P2 − 3P1) lines in every target observed. In about half of the observed targets, we also detected [C i] 609 μm (3P1 – 3P0).
A Herschel Survey of the [N ii] 205 μm Emission in Local Infrared Luminous Galaxies
Authors: Zhao Yinghe , Lu Nanyao , Xu C. Kevin , Gao Yu ,   GOALS FTS Team
Published: March 2013

AbstractThe [N ii] line is a major coolant in ionized interstellar medium, and is expected to be a good star formation rate indicator. Here we present a statistical study of [N ii] line emission for a large sample of local luminous infrared galaxies (LIRGs) using Herschel SPIRE FTS data (Lu et al. 2012; Zhao et al. 2012, in preparation). For our sample of galaxies, the [N ii] to the total infrared luminosity ratio (L[Nii]/LIR) varies from ∼ 10−5 to ∼ 10−4. We investigate the correlation between L[Nii] and LIR, as well as the dependence of L[Nii]/LIR on LIR, infrared colors (f60/f100) and the OIII 88 μm to [N ii] luminosity ratio. We find that L[Nii] strongly, and almost linearly correlates with LIR for star-forming galaxies, namely log LIR = (4.23 ± 0.33) + (0.99 ± 0.05) log L[NII] (see Fig. 1). The scatter in this relation is mainly due to the variation of hardness, and/or high ionization parameter, of the background UV field.
The Origin of Unidentified Infrared Emission Features in Galaxies
Authors: Kwok Sun 
Published: March 2013

AbstractThe family of unidentified infrared emission features, consisting of discrete and plateau features in the mid-infrared, are now observed in distant galaxies. A significant fraction of the total energy output of some infrared galaxies is emitted in these features. Comparisons of these features with those observed in the circumstellar and interstellar media suggest that these organic species are synthesized and ejected by evolved stars. Models of possible chemical structures of the carrier of these features are discussed.
GOODS-Herschel: Dust attenuation up to z∼4
Authors: Pannella M. , Elbaz D. , Daddi E. 
Published: March 2013

AbstractWe quantitatively explore in a unbiased way the evolution of dust attenuation up to z ≈ 4 as a function of galaxy properties. We have used one of the deepest datasets available at present, in the GOODS-N field, to select a star forming galaxy sample and robustly measure galaxy redshifts, star formation rates, stellar masses and UV restframe properties. Our main results can be summarized as follows: i) we confirm that galaxy stellar mass is a main driver of UV dust attenuation in star forming galaxies: more massive galaxies are more dust attenuated than less massive ones; ii) strikingly, we find that the correlation does not evolve with redshift: the amount of dust attenuation is the same at all cosmic epochs for a fixed stellar mass; iii) this finding explains why and how the SFR–AUV relation evolves with redshift: the same amount of star formation is less attenuated at higher redshift because it is hosted in less massive galaxies; iv) combining our finding with results from line emission surveys, we confirm that line reddening is larger than continuum reddening, at least up to z ≈ 1.5; v) given the redshift evolution of the mass-metallicity relation, we predict that star forming galaxies at a fixed metal content are more attenuated at high redshift. Finally, we explored the correlation between UV dust attenuation and the spectral slope: vi) the correlation is evolving with redshift with star forming galaxies at lower redshift having redder spectra than higher redshift ones for the same amount of dust attenuation.
Resolved Schmidt-Kennicutt Relation for Star Forming Regions in the Galaxy and Magellanic Clouds
Authors: Chen C.-H. R. , Indebetouw R. , Muller E. , Messineo M. , Menten K. M. ,   the SAGE-SMC Team
Published: March 2013

AbstractThe relationship between star formation rate (SFR) and the gas surface density (Σgas) is one of the most critical links between star formation and galaxy evolution. The observed SFR- Σgas relation, the “Schmidt-Kennicutt (S-K) law”, is tight when properties are averaged over kpc, but breaks down at the scale of giant molecular clouds (GMCs). To understand the physics governing the variations at GMC scales and the tight correlation at kpc scales, spatially and temporally resolved data covering a wide range of linear scale are needed. We have used the Spitzer surveys of the Large Magellanic Cloud and Magellanic Bridge to identify massive young stellar objects (YSOs), estimate “instantaneous” SFRs, and compare them to the S-K relation. These instantaneous SFRs are further compared to that estimated from integrated Hα and 24 μm luminosities to examine how SFRs vary on 10 Myr timescales. We have also used SINFONI near-IR integral field spectra of two Galactic mini-starbursts W31 and W43 to determine their underlying massive stellar content, estimate the SFRs, and compare to the S-K relation. To investigate evironmental effects on star formation, we have used complete YSO samples in the LMC and the Bridge to estimate global star formation efficiencies (SFE) in these two systems.
Star formation laws in extreme starbursts
Authors: García-Burillo S. , Usero A. , Alonso-Herrero A. 
Published: March 2013

AbstractThe observational study of star formation laws is paramount to disentangling the physical processes at work on local and global scales in galaxies. To this aim we have expanded the sample of extreme starbursts, represented by local LIRGs and ULIRGs, with high-quality data obtained in the 1-0 line of HCN. The analysis of the new data shows that the star formation efficiency of the dense molecular gas, derived from the FIR/HCN luminosity ratio, is a factor 3-4 higher in extreme starbursts compared to normal galaxies. We find a duality in the Kennicutt-Schmidt laws that is enhanced if we account for the different conversion factor for HCN (αHCN) in extreme starbursts and correct for the unobscured star formation rate in normal galaxies. We find that it is possible to fit the observed differences in the FIR/HCN ratios between normal galaxies and LIRGs/ULIRGs with a common constant star formation rate per free-fall time (SFRff) if we assume that HCN densities are ∼1–2 orders of magnitude higher in LIRGs/ULIRGs, and provided that SFRff∼0.005-0.01 and/or if αHCN is a factor of a few lower than our favored values.
Probing the star–formation modes in merging galaxies
Authors: Duc P.-A. , Belles P.-E. , Brinks E. , Bournaud F. 
Published: March 2013

AbstractMerging systems at low redshift provide the unique opportunity to study the processes related to star formation in a variety of environments that presumably resemble those seen at higher redshifts. Previous studies of distant starbursting galaxies suggest that stars are born in turbulent gas, with a higher efficiency than in MW-like spirals. We have investigated in detail the turbulent-driven regime of star-formation in nearby colliding galaxies combining high resolution VLA B array Hi maps and UV GALEX observations. With these data, we could check predictions of our state-of-the-art simulations of mergers, such as the global sharp increase of the fraction of dense gas, as traced by the SFR, with respect to the diffuse gas traced by Hi during the merging stage, following the increased velocity dispersion of the gas. We present here initial results obtained studying the SFR-Hi relation at 4.5 kpc resolution. We determined SFR/Hi mass ratios that are higher in the external regions of mergers than in the outskirts of isolated spirals, though both environments are Hi dominated. SFR/Hi increases towards the central regions following the decrease of the atomic gas fraction and possibly the increased star–formation efficiency. These results need to be checked with a larger sample of systems and on smaller spatial scales. This is the goal of the on-going Chaotic THINGS project that ultimately will allow us to determine why starbursting galaxies deviate from the Kennicutt-Schmidt relation between SFR density and gas surface density.
Anatomy of Starbursts in Extragalactic Giant HII Regions: M51 Case Study
Authors: Evans Jessica Marie , Chu You-Hua 
Published: March 2013

AbstractExtragalactic giant HII regions (EGHRs) are sites of active, concentrated star formation, and thus provide excellent labs to analyze the starburst phenomenon. Although they have been known for a long time, ground-based observations cannot resolve the physical structures and stellar content of EGHRs. The high resolution and sensitivity of Hubble Space Telescope (HST) are ideal for detailed studies of EGHRs. We have searched the Hubble Legacy Archives (HLA) and found 17 nearby galaxies, within ∼15 Mpc, with Hα and continuum images; to determine the best methods for analyzing these data, we perform an in-depth analysis of the EGHRs in M51. M51 is a face-on spiral galaxy ∼8.4 Mpc away, with well-resolved multi-wavelength observations in the HLA. We sample the 25 most luminous HII regions in M51, many of which are bonafide EGHRs with an H-alpha luminosity > 1039 ergs s−1. We use the Hα image to study the distribution and physical structure of the gas in each HII region and determine its Hα luminosity and required ionizing flux. We use the continuum images to determine whether super stellar clusters (SSCs) are found in these HII regions, and use photometric measurements to determine the mass and age spread of the resolved stellar population. These are then compared with the interstellar structures. The results help us provide the groundwork for studying EGHRs in multiple galaxies and elucidate the starburst phenomenon by investigating questions such as: What role does environment play in the formation of EGHRs? How do EGHRs evolve? How does star formation proceed in an EGHR?
Feedback and Outflows
Authors: Murray Norman 
Published: March 2013

AbstractThe low stellar and gas mass fractions, low galaxy-wide star formation rates (relative to galactic dynamical times) and observations of rapid outflows from galaxies, all suggest that stars and active galactic nuclei violently alter the state of the interstellar and even inter-halo gas in galaxies. I argue that the low galaxy wide star formation rates are not the result of turbulent suppression of star formation on small scale, but rather the result of a balance between dynamical pressure and the force (or rate of momentum deposition) provided by stellar feedback, either in the form of radiation pressure or by supernovae. Galaxy scale winds can also be driven by feedback, either from stars or active galactic nuclei, although the exact mechanisms involved are still not well determined.
Measuring AGN Feedback Parameters From Seyfert Galaxy Outflows
Authors: Müller-Sánchez F. , Malkan M. , Hicks E. K. S. , Davies R. I. 
Published: March 2013

AbstractWe present results of an on-going program to measure AGN feedback in Seyfert galaxies using integral-field spectroscopy and adaptive optics at Keck Observatory and VLT. Our integral-field observations are revealing AGN-driven outflows of ionized gas in Seyfert galaxies. By resolving the inner 10–40 parsecs, we are successfully modeling them as biconical structures, in which the ionized gas first accelerates and then decelerates. The model parameters provide crucial information on the orientation, geometry and kinematics of the outflows, which is used to estimate mechanical feedback from the AGN: mass and kinetic energy transferred to the interstellar medium. Mass outflow rates can be 102–104 times greater than accretion rates, but in some cases, they are comparable to the estimated inflow rates to the central 10–25 pc, suggesting that the outflows may remove a considerable amount of the infalling gas before it reaches the accretion disk. In half of the AGN measured so far, the kinetic energy of the outflows appears sufficient to provide the eagerly-sought AGN feedback invoked to explain fundamental galaxy properties such as the MBH − σ* relation (0.5–5 Lbol). The other AGN, which lack powerful outflows, also have weaker and more compact radio jets.
Do AGN suppress star formation in disc-dominated galaxies?
Authors: Husemann B. , Walcher J. , Wisotzki L. , Gerssen J. , Jahnke K. , Sánchez S. F. , Wild V. 
Published: March 2013

AbstractWe present preliminary results of our integral field spectroscopy (IFS) observations to test whether AGN can suppress star formation in disc-dominated galaxies. We find a lower specific star formation rate and a different radial Hα profile for AGN than in the control sample.
Heat-shock factor 1 both positively and negatively affects cellular clonogenic growth depending on p53 status
Authors: Nguyen Chau H. , Lang Benjamin J. , Chai Ryan C. C. , Vieusseux Jessica L. , Kouspou Michelle M. , Price John T. 
Published: March 2013

HSF1 (heat-shock factor 1) is the master regulator of the heat-shock response; however, it is also activated by cancer-associated stresses and supports cellular transformation and cancer progression. We examined the role of HSF1 in relation to cancer cell clonogenicity, an important attribute of cancer cells. Ectopic expression or HSF1 knockdown demonstrated that HSF1 positively regulated cancer cell clonogenic growth. Furthermore, knockdown of mutant p53 indicated that HSF1 actions were mediated via a mutant p53-dependent mechanism. To examine this relationship more specifically, we ectopically co-expressed mutant p53R273H and HSF1 in the human mammary epithelial cell line MCF10A. Surprisingly, within this cellular context, HSF1 inhibited clonogenicity. However, upon specific knockdown of endogenous wild-type p53, leaving mutant p53R273H expression intact, HSF1 was observed to greatly enhance clonogenic growth of the cells, indicating that HSF1 suppressed clonogenicity via wild-type p53. To confirm this we ectopically expressed HSF1 in non-transformed and H-RasV12-transformed MCF10A cells. As expected, HSF1 significantly reduced clonogenicity, altering wild-type p53 target gene expression levels consistent with a role of HSF1 increasing wild-type p53 activity. In support of this finding, knockdown of wild-type p53 negated the inhibitory effects of HSF1 expression. We thus show that HSF1 can affect clonogenic growth in a p53 context-dependent manner, and can act via both mutant and wild-type p53 to bring about divergent effects upon clonogenicity. These findings have important implications for our understanding of HSF1's divergent roles in cancer cell growth and survival as well as its disparate effect on mutant and wild-type p53.
Miniature multi‐band monopole antenna using spiral ring resonators for radiation pattern characteristics improvement
Authors: Wan Y.‐T. , Yu D. , Zhang F.‐S. , Zhang F. 
Published: March 2013

A compact coplanar waveguide (CPW)‐fed multi‐band monopole antenna loaded with spiral ring resonators is presented. The proposed antenna consists of two spiral ring strips which are printed on the different sides of the substrate and connected through a via‐hole. The size of the miniaturised antenna is only about 27.5 × 20 × 1 mm3. The proposed antenna can excite multi‐resonant modes close to the 2.5/3.5/5.5 GHz bands to meet the specifications of the worldwide interoperability for microwave access (WiMAX) system. By introducing the spiral ring structure, very good radiation pattern characteristics can be obtained. With a figure‐of‐eight pattern in the E‐plane and omnidirectional pattern in the H‐plane, measured peak gains are about 2.0/2.23/2.58 dBi at the 2.5/3.5/5.5 GHz operating bands, respectively.
MEMS‐based piezoelectric BAW resonator based on out‐of‐plane degenerate mode for micro angular detector
Authors: Cheng Y.X. , Zhang W.P. , Guan R. , Zhang G. , Xu Z.X. , Chen W.Y. 
Published: March 2013

A novel microelectromechanical piezoelectric concentrated‐mass bulk acoustic wave (BAW) resonator based on out‐of‐plane degenerate mode is proposed for detecting micro angles. A PZT resonator with a concentrated‐mass is designed to enhance the driving and sensing efficiency. The device combines the bulk acoustic wave drive/sense with a rocking concentrated mass to increase the resonant frequency, the signal quality and the resolution of the sensor. A 10 × 10 mm device has been fabricated and assembled by the microelectromechanical system process and the traditional mechanical process. The test results measured by the impedance analyser in air show that the resonant frequency and the quality factor of this device are about 174 kHz and 110, respectively. Moreover, the frequency split is only about 200Hz without any tuning methods.
High‐breakdown voltage and low on‐resistance AlGaN/GaN on Si MOS‐HEMTs employing an extended TaN gate on HfO2 gate insulator
Authors: Seok O. , Ahn W. , Han M.‐K. , Ha M.‐W. 
Published: March 2013

Proposed is a new extended gate towards a source in AlGaN/GaN metal‐oxide‐semiconductor–high‐electron‐mobility transistors (MOS‐HEMTs) in order to increase breakdown voltage and reduce on‐resistance. The TaN gate was isolated from the source by a 15 nm‐thick RF‐sputtered HfO2 gate insulator. A high breakdown voltage of 1410 V was measured as a result of the successfully blocked gate leakage current and surface passivation by the HfO2 gate insulator. The extended gate towards the source was an effective method to improve the on‐resistance and drain current density by eliminating the gate‐source space. The proposed device with the extended gate exhibited low specific on‐resistance of 2.28 mΩ·cm2 while that of the MOS‐HEMT with the conventional structure was 2.91 mΩ·cm2. Also, maximum drain current density at the VGS of 2 V was increased from 332 to 420 mA/mm by the proposed extended TaN gate.
Monitoring injury reporting in selected Australian media: a potential advocacy strategy?
Authors: Stoneham Melissa , Boss Andrea , Daube Mike 
Published: March 2013

Issue addressedThis review of injury articles describes how selected primary print media sources in Australia report injury events and explores how this may impact on public perception of the injury risk and the opportunities it may present to health professionals.MethodsMedia articles specific to injury, compiled by the Public Health Advocacy Institute of Western Australia (PHAIWA) through their MediaWatch service during 2011, were collated and analysed. Articles were gathered from The West Australian, The Australian and The Sunday Times newspapers and ABC Online. Each article was categorised into injury topics and target groups, and preventive strategies were identified.ResultsOf the 546 articles that contained injury as a Key word, 424 articles were used for the present study. The majority of articles related to community‐based injuries (65%) and the most frequent reported injury was violence and assault. The results also indicate that although there is regular media reporting on injury issues, only one‐fifth of reports discuss possible preventive measures.ConclusionsSelected Australian newspapers and the ABC Online are important and low‐cost sources of injury‐related information for the general public and can impact how the public perceives injury. It is important for public health professionals to embrace media advocacy strategies to assist in influencing and setting local public policy.So what?Public attitudes and understanding of issues are influenced by media coverage. Media monitoring is one tool to track what media sources are reporting about public health issues, the industry and stakeholders. Influencing the quantity and quality of media coverage is critical to advancing healthy public policy, particularly when advocating for prevention strategies to be reported and acted upon. Advocacy is an important health promotion strategy; it is therefore important for health professionals to understand media advocacy and position public health issues as societal issues with policy solutions.
Anxieties of Legitimacy: The Origins and Influence of the “Classicist Stance” in American Rhetoric Studies
Authors: Kalbfleisch Elizabeth 
Published: March 2013

ABSTRACTThis article describes an origin of the “classicist stance,” Nan Johnson's term for the emphasis on the classical past in American rhetoric historiography. It argues that adherence to the classical past arises from an anxiety about conducting research evident in the field in the early twentieth century, an anxiety that develops into fears about institutional legitimacy later in the century. The article closes by urging scholars of rhetoric in the modern era to embrace print modernity as their researh framework, rather than classicism.
PHISTO: pathogen–host interaction search tool
Authors: Durmuş Tekir Saliha , Çakır Tunahan , Ardıç Emre , Sayılırbaş Ali Semih , Konuk Gökhan , Konuk Mithat , Sarıyer Hasret , Uğurlu Azat , Karadeniz İlknur , Özgür Arzucan , Sevilgen Fatih Erdoğan , Ülgen Kutlu Ö. 
Published: March 2013

Abstract
Summary: Knowledge of pathogen–host protein interactions is required to better understand infection mechanisms. The pathogen–host interaction search tool (PHISTO) is a web-accessible platform that provides relevant information about pathogen–host interactions (PHIs). It enables access to the most up-to-date PHI data for all pathogen types for which experimentally verified protein interactions with human are available. The platform also offers integrated tools for visualization of PHI networks, graph–theoretical analysis of targeted human proteins, BLAST search and text mining for detecting missing experimental methods. PHISTO will facilitate PHI studies that provide potential therapeutic targets for infectious diseases.
Availability: http://www.phisto.org.
Contact: saliha.durmus@boun.edu.tr
Supplementary information: Supplementary data are available at Bioinformatics online.