153 research outputs found
Spin-valley phase diagram of the two-dimensional metal-insulator transition
Using symmetry breaking strain to tune the valley occupation of a
two-dimensional (2D) electron system in an AlAs quantum well, together with an
applied in-plane magnetic field to tune the spin polarization, we independently
control the system's valley and spin degrees of freedom and map out a
spin-valley phase diagram for the 2D metal-insulator transition. The insulating
phase occurs in the quadrant where the system is both spin- and
valley-polarized. This observation establishes the equivalent roles of spin and
valley degrees of freedom in the 2D metal-insulator transition.Comment: 4 pages, 2 figure
Systematic review: conservative treatments for secondary lymphedema
<p>Abstract</p> <p>Background</p> <p>Several conservative (i.e., nonpharmacologic, nonsurgical) treatments exist for secondary lymphedema. The optimal treatment is unknown. We examined the effectiveness of conservative treatments for secondary lymphedema, as well as harms related to these treatments.</p> <p>Methods</p> <p>We searched MEDLINE<sup>®</sup>, EMBASE<sup>®</sup>, Cochrane Central Register of Controlled Trials<sup>®</sup>, AMED, and CINAHL from 1990 to January 19, 2010. We obtained English- and non-English-language randomized controlled trials or observational studies (with comparison groups) that reported primary effectiveness data on conservative treatments for secondary lymphedema. For English-language studies, we extracted data in tabular form and summarized the tables descriptively. For non-English-language studies, we summarized the results descriptively and discussed similarities with the English-language studies.</p> <p>Results</p> <p>Thirty-six English-language and eight non-English-language studies were included in the review. Most of these studies involved upper-limb lymphedema secondary to breast cancer. Despite lymphedema's chronicity, lengths of follow-up in most studies were under 6 months. Many trial reports contained inadequate descriptions of randomization, blinding, and methods to assess harms. Most observational studies did not control for confounding. Many studies showed that active treatments reduced the size of lymphatic limbs, although extensive between-study heterogeneity in areas such as treatment comparisons and protocols, and outcome measures, prevented us from assessing whether any one treatment was superior. This heterogeneity also precluded us from statistically pooling results. Harms were rare (< 1% incidence) and mostly minor (e.g., headache, arm pain).</p> <p>Conclusions</p> <p>The literature contains no evidence to suggest the most effective treatment for secondary lymphedema. Harms are few and unlikely to cause major clinical problems.</p
IL-22 Is Produced by Innate Lymphoid Cells and Limits Inflammation in Allergic Airway Disease
Interleukin (IL)-22 is an effector cytokine, which acts primarily on epithelial cells in the skin, gut, liver and lung. Both pro- and anti-inflammatory properties have been reported for IL-22 depending on the tissue and disease model. In a murine model of allergic airway inflammation, we found that IL-22 is predominantly produced by innate lymphoid cells in the inflamed lungs, rather than TH cells. To determine the impact of IL-22 on airway inflammation, we used allergen-sensitized IL-22-deficient mice and found that they suffer from significantly higher airway hyperreactivity upon airway challenge. IL-22-deficiency led to increased eosinophil infiltration lymphocyte invasion and production of CCL17 (TARC), IL-5 and IL-13 in the lung. Mice treated with IL-22 before antigen challenge displayed reduced expression of CCL17 and IL-13 and significant amelioration of airway constriction and inflammation. We conclude that innate IL-22 limits airway inflammation, tissue damage and clinical decline in allergic lung disease
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Latent provisions for building information modeling (BIM) contracts: a social network analysis approach
The effective adoption and use of Building Information Modeling (BIM) require appropriate contract design to fairly allocate the contracting parties’ rights and responsibilities. Several standards for BIM protocols and contracts have been developed for the industry. However, the awareness and the use of these are rather limited, leading to unclear provisions in BIM contracts. Therefore, the research aims to identify the influential legal aspects that serve as the latent contract provisions in BIM contracts. A questionnaire survey was conducted to survey experts and active BIM users in construction projects. The data were analyzed using social network analysis (SNA) by assuming interdependent relationships among various the legal aspects in BIM contacts. The key legal aspects associated with BIM contracts pertain to the roles and responsibilities of the project participants. The results also reveal that data security is the center of all latent legal aspects in the contracts. The study provides significant new insights into clarifying the required contract provisions in BIM contracts
Total eclipse of the heart: the AM CVn Gaia14aae/ASSASN-14cn
We report the discovery and characterization of a deeply eclipsing AM CVn-system, Gaia14aae (=ASSASN-14cn). Gaia14aae was identified independently by the All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al.) and by the Gaia Science Alerts project, during two separate outbursts. A third outburst is seen in archival Pan-STARRS-1 (PS1; Schlafly et al.; Tonry et al.; Magnier et al.) and ASAS-SN data. Spectroscopy reveals a hot, hydrogen-deficient spectrum with clear double-peaked emission lines, consistent with an accreting double-degenerate classification. We use follow-up photometry to constrain the orbital parameters of the system. We find an orbital period of 49.71min, which places Gaia14aae at the long period extremum of the outbursting AM CVn period distribution. Gaia14aae is dominated by the light from its accreting white dwarf (WD). Assuming an orbital inclination of 90° for the binary system, the contact phases of the WD lead to lower limits of 0.78 and 0.015M⊙ on the masses of the accretor and donor, respectively, and a lower limit on the mass ratio of 0.019. Gaia14aae is only the third eclipsing AM CVn star known, and the first in which the WD is totally eclipsed. Using a helium WD model, we estimate the accretor's effective temperature to be 12 900 ± 200K. The three outburst events occurred within four months of each other, while no other outburst activity is seen in the previous 8yr of Catalina Real-time Transient Survey (CRTS; Drake et al.), Pan-STARRS-1 and ASAS-SN data. This suggests that these events might be rebrightenings of the first outburst rather than individual event
Final Targeting Strategy for the SDSS-IV APOGEE-2N Survey
APOGEE-2 is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with
the goal of producing a chemo-dynamical mapping of the Milky Way Galaxy. The
targeting for APOGEE-2 is complex and has evolved with time. In this paper, we
present the updates and additions to the initial targeting strategy for
APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two
implementation modes: (i) "Ancillary Science Programs" competitively awarded to
SDSS-IV PIs through proposal calls in 2015 and 2017 for the pursuit of new
scientific avenues outside the main survey, and (ii) an effective 1.5-year
expansion of the survey, known as the Bright Time Extension, made possible
through accrued efficiency gains over the first years of the APOGEE-2N project.
For the 23 distinct ancillary programs, we provide descriptions of the
scientific aims, target selection, and how to identify these targets within the
APOGEE-2 sample. The Bright Time Extension permitted changes to the main survey
strategy, the inclusion of new programs in response to scientific discoveries
or to exploit major new datasets not available at the outset of the survey
design, and expansions of existing programs to enhance their scientific success
and reach. After describing the motivations, implementation, and assessment of
these programs, we also leave a summary of lessons learned from nearly a decade
of APOGEE-1 and APOGEE-2 survey operations. A companion paper, Santana et al.
(submitted), provides a complementary presentation of targeting modifications
relevant to APOGEE-2 operations in the Southern Hemisphere.Comment: 59 pages; 11 Figures; 7 Tables; 2 Appendices; Submitted to Journal
and Under Review; Posting to accompany papers using the SDSS-IV/APOGEE-2 Data
Release 17 scheduled for December 202
Space Telescope and Optical Reverberation Mapping Project. XII. broad-line region modeling of NGC 5548.
We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the Hβ, C iv, and Lyα broad emission lines. We find an extended disk-like Hβ BLR with a mixture of near-circular and outflowing gas trajectories, while the C iv and Lyα BLRs are much less extended and resemble shell-like structures. There is clear radial structure in the BLR, with C iv and Lyα emission arising at smaller radii than the Hβ emission. Using the three lines, we make three independent black hole mass measurements, all of which are consistent. Combining these results gives a joint inference of . We examine the effect of using the V band instead of the UV continuum light curve on the results and find a size difference that is consistent with the measured UV–optical time lag, but the other structural and kinematic parameters remain unchanged, suggesting that the V band is a suitable proxy for the ionizing continuum when exploring the BLR structure and kinematics. Finally, we compare the Hβ results to similar models of data obtained in 2008 when the active galactic nucleus was at a lower luminosity state. We find that the size of the emitting region increased during this time period, but the geometry and black hole mass remained unchanged, which confirms that the BLR kinematics suitably gauge the gravitational field of the central black hole
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
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