168 research outputs found
Stars were born in significantly denser regions in the early Universe
The density of the warm ionized gas in high-redshift galaxies is known to be
higher than what is typical in local galaxies on similar scales. At the same
time, the mean global properties of the high- and low-redshift galaxies are
quite different. Here, we present a detailed differential analysis of the
ionization parameters of 14 star-forming galaxies at redshift 2.6-3.4, compiled
from the literature. For each of those high-redshift galaxies, we construct a
comparison sample of low-redshift galaxies closely matched in specific star
formation rate (sSFR) and stellar mass, thus ensuring that their global
physical conditions are similar to the high-redshift galaxy. We find that the
median log [OIII] 5007/ [OII] 3727 line ratio of the high-redshift galaxies is
0.5 dex higher than their local counterparts. We construct a new calibration
between the [OIII] 5007/ [OII] 3727 emission line ratio and ionization
parameter to estimate the difference between the ionization parameters in the
high and low-redshift samples. Using this, we show that the typical density of
the warm ionized gas in star-forming regions decreases by a median factor of
from z ~ 3.3 to z ~ 0 at fixed mass and sSFR. We show that
metallicity differences cannot explain the observed density differences.
Because the high- and low-redshift samples are comparable in size, we infer
that the relationship between star formation rate density and gas density must
have been significantly less efficient at z ~2-3 than what is observed in
nearby galaxies with similar levels of star formation activity.Comment: 16 pages, 6 figures, accepted for publication in Ap
Comparison between Impact factor, SCImago journal rank indicator and Eigenfactor score of nuclear medicine journals
Despite its widespread acceptance in the scientific world, impactfactor (IF) has been criticized recently on many accounts:including lack of quality assessment of the citations, influenceof self citation, English language bias, etc. In the current study,we evaluated three indices of journal scientific impact: (IF),Eigenfactor Score (ES), and SCImago Journal rank indicator(SJR) of nuclear medicine journals. Overall 13 nuclear medicinejournals are indexed in ISI and SCOPUS and 7 in SCOPUSonly. Self citations, Citations to non-English articles, citationsto non-citable items and citations to review articles contributeto IFs of some journals very prominently, which can be betterdetected by ES and SJR to some extent. Considering all threeindices while judging quality of the nuclear medicine journalswould be a better strategy due to several shortcomings of IF.Despite its widespread acceptance in the scientific world, impactfactor (IF) has been criticized recently on many accounts:including lack of quality assessment of the citations, influenceof self citation, English language bias, etc. In the current study,we evaluated three indices of journal scientific impact: (IF),Eigenfactor Score (ES), and SCImago Journal rank indicator(SJR) of nuclear medicine journals. Overall 13 nuclear medicinejournals are indexed in ISI and SCOPUS and 7 in SCOPUSonly. Self citations, Citations to non-English articles, citationsto non-citable items and citations to review articles contributeto IFs of some journals very prominently, which can be betterdetected by ES and SJR to some extent. Considering all threeindices while judging quality of the nuclear medicine journalswould be a better strategy due to several shortcomings of IF
Investigating User Needs for Bio-sensing and Affective Wearables
Bio-sensing wearables are currently advancing to provide users with a lot of information about their physiological and affective states. However, relatively little is known about users' interest in acquiring, sharing and receiving this information and through which channels and modalities. To close this gap, we report on the results of an online survey (N=109) exploring principle aspects of the design space of wearables such as data types, contexts, feedback modalities and sharing behaviors. Results show that users are interested in obtaining physiological, emotional and cognitive data through modalities beyond traditional touchscreen output. Valence of the information, whether positive or negative affects the sharing behaviors
A New Three-Layer Model for Horizontal Slurry Flow
Paper presented at 2018 Canadian Society of Mechanical Engineers International Congress, 27-30 May 2018.A modified three-layer model for solid-liquid flow in horizontal pipes is developed, which overcomes the limitations of many previous models. The steady-state model predicts the pressure loss, critical velocity, concentration profile in the heterogeneous layer, mean heterogeneous layer and moving bed layer velocities, and bed layer heights for each set of parameters. We propose a new correlation for the turbulent solids diffusivity. This and the steady state model predictions show a good agreement with experimentally measured results in literature: for concentration profile in the heterogeneous layer and pressure loss, over a wide range of conditions [1]. In turbulent flow. the pressure loss vs mean velocity curve shows a characteristic minimum just before the critical velocity is attained
Double Antibiotic Paste for Management of External Inflammatory Root Resorption
External inflammatory root resorption (EIRR) is one of the common complications following dental trauma which when remained untreated, may lead to tooth loss. Successful treatment outcomes depend on elimination of bacteria from root canal system and apical sealing. This case presents the endodontic management of an EIRR that was nonresponsive to calcium hydroxide (CH) therapy. An 11-year-old boy was referred for management of a traumatized maxillary central incisor. Tooth #8 was symptom-free, nonresponsive to vitality pulp tests and had an immature root with sever EIRR. Using chemomechanical debridement and CH dressing, the treatment was initiated. The tooth was remained asymptomatic; however, after five weeks the size of periradicular lesion increased and intracanal exudate was present, signifying a resistant endodontic infection. In second appointment, double antibiotic paste (DAP; ciprofloxacin/metronidazole) was applied to the canal. Eight weeks later, the tooth continued to be asymptomatic and the size of the lesion decreased. Finally, the root canal was entirely obturated with calcium-enriched mixture (CEM). At 18-month follow-up, the tooth was asymptomatic/functional, EIRR did not further progress and tooth discoloration was not observed. Based on the results, DAP has the potential to be used to manage the CH-resistant endodontic infection. Furthermore, CEM root filling/sealing seems to be an applicable choice in EIRR management.Keywords: Antibiotics; Calcium-Enriched Mixture; CEM Cement; Dental Trauma; Endodontics; Intracanal Medicament; Root Resorption
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