3,115 research outputs found
Comparison of the poleward transport of ozone in the Northern and Southern Hemispheres
Six and one-half years of ozone data and temperature data are used to extend Geller et al.'s (1988) study comparing the transport of ozone to high latitudes in the Northern and Southern Hemispheres. In this earlier study, it was pointed out that the poleward transport of ozone varies annually in the Northern Hemisphere but has a marked semiannual behavior in the Southern Hemisphere. This earlier study covered the period from December 1978 to November 1982. Two and one-half additional years have now been analyzed so that the analysis now extends to July 1986. With this extended data set, the maximum rate of increase in total ozone is seen to occur in January in the Northern Hemisphere for all of the years investigated. In the Southern Hemisphere, the maximum rate of increase is seen in September for almost all of the years with a secondary maximum in the rate of increase in total ozone often being seen during March-April period. The nature of the seasonal variation in total ozone is found to be much more variable in the Southern Hemisphere than in the Northern Hemisphere
The origin and properties of massive prolate galaxies in the Illustris simulation
We study galaxy shapes in the Illustris cosmological hydrodynamic simulation.
We find that massive galaxies have a higher probability of being prolate. For
galaxies with stellar mass larger than , 35 out of total
839 galaxies are prolate. For 21 galaxies with stellar mass larger than
, 9 are prolate, 4 are triaxial while the others are
close to being oblate. There are almost no prolate galaxies with stellar mass
smaller than . We check the merger history of the
prolate galaxies, and find that they are formed by major dry mergers. All the
prolate galaxies have at least one such merger, with most having mass ratios
between and . The gas fraction (gas mass to total baryon mass) of
the progenitors is 0-3 percent for nearly all these mergers, except for one
whose second progenitor contains gas mass, while its main
progenitor still contains less than . For the 35 massive prolate galaxies
that we find, 18 of them have minor axis rotation, and their angular momenta
mostly come from the spin angular momenta of the progenitors (usually that of
the main progenitor). We analyse the merger orbits of these prolate galaxies
and find that most of them experienced a nearly radial merger orbit. Oblate
galaxies with major dry mergers can have either radial or circular merger
orbits. We further discuss various properties of these prolate galaxies, such
as spin parameter , spherical anisotropy parameter ,
dark matter fraction, as well as inner density slopes for the stellar, dark
matter and total mass distributions.Comment: Accepted for publication in MNRAS. 24 pages, 14 figure
SDSS-IV MaNGA: The intrinsic shape of slow rotator early-type galaxies
By inverting the distributions of galaxies' apparent ellipticities and
misalignment angles (measured around the projected half-light radius ) between their photometric and kinematic axes, we study the intrinsic shape
distribution of 189 slow rotator early-type galaxies with stellar masses
, extracted from a
sample of about 2200 galaxies with integral-field stellar kinematics from the
DR14 of the SDSS-IV MaNGA IFU survey. Thanks to the large sample of slow
rotators, Graham+18 showed that there is clear structure in the misalignment
angle distribution, with two peaks at both and
misalignment (characteristic of oblate and prolate rotation respectively). Here
we invert the observed distribution from Graham+18. The large sample allows us
to go beyond the known fact that slow rotators are weakly triaxial and to place
useful constraints on their intrinsic triaxiality distribution (around ) for the first time. The shape inversion is generally non-unique. However,
we find that, for a wide set of model assumptions, the observed distribution
clearly requires a dominant triaxial-oblate population. For some of our models,
the data suggest a hint for a minor triaxial-prolate population, but a dominant
prolate population is ruled out.Comment: Accepted for publication in ApJL, 10 pages, 4 figures, 1 tabl
Residual circulations calculated from satellite data: Their relations to observed temperature and ozone distributions
Monthly mean residual circulations were calculated from eight years of satellite data. The diabatic circulation is usually found to give a good approximation to the residual circulation, but this is not always the case. In particular, an example is shown at 60 deg S and 30 mbar where the diabatic and residual circulations show very different annual variations. Correlations between the vertical component of the residual circulation and temperature and ozone were computed. The computations indicate that yearly variations of temperatures in the tropics are under radiative control, except during stratospheric warmings. Interannual variations in seasonal mean temperatures are shown to be under dynamical control everywhere. Correlations between seasonal means of the vertical component of the residual circulation and ozone mixing ratios are consistent with what would be expected from the ozone variations being due to differences in the ozone transport, although transport effects cannot easily be distinguished from photochemical effects above the altitude of the ozone mixing ratio peak. Finally, variations in total ozone are examined in comparison with residual circulation variations. A one to two month phase lag is seen in the annual variation in the total ozone at 60 deg N with respect to the maximum downward residual motions. This phase lag is greater at 60 deg N than at 60 deg S. There is evidence at 60 deg S of a greater downward trend in the mean zonal ozone maxima than there is in the minima. A decreasing trend in the maximum descending motion is seen to accompany the ozone trend at 60 deg S
Clostridium septicum Sepsis and Colon Carcinoma: Report of 4 Cases
An association exists between colon carcinoma and Clostridium septicum infection, especially bacteremia. We reviewed retrospectively all positive blood cultures for this organism at a 300-bed general hospital over 4 years. Four of 15 cases were associated with concurrent colon carcinoma. C. septicum infection was the presenting feature of previously undiagnosed large bowel malignancy in three patients. We report this small case series to alert clinicians to the diverse spectrum and diagnostic difficulties of this rare, potentially catastrophic association. Although commonly associated with necrotizing skin or soft tissue infections, this bacterium can present with nonspecific or atypical symptoms. All patients with positive blood cultures for C. septicum, even without clinical suspicion of large bowel malignancy, should undergo colonoscopy to evaluate for colon carcinoma
Ionic liquid-containing cathodes empowering ceramic solid electrolytes
Although ceramic solid electrolytes, such as Li7La3Zr2O12 (LLZO), are promising candidates to replace conventional liquid electrolytes for developing safe and high-energy-density solid-state Li-metal batteries, the large interfacial resistance between cathodes and ceramic solid electrolytes severely limits their practical application. Here we developed an ionic liquid (IL)-containing while nonfluidic quasi-solid-state LiCoO2 (LCO) composite cathode, which can maintain good contact with an Al-doped LLZO (Al-LLZO) ceramic electrolyte. Accordingly the interfacial resistance between LCO and Al-LLZO was significantly decreased. Quasi-solid-state LCO/Al-LLZO/Li cells demonstrated relatively high capacity retention of about 80% after 100 cycles at 60°C. The capacity decay was mainly because of the instability of the IL. Nevertheless, the IL-containing LCO cathode enabled the use of Al-LLZO as a solid electrolyte in a simple and practical way. Identifying a suitable IL is critical for the development of quasi-solid-state Li-metal batteries with a ceramic solid electrolyte
GPT detectors are biased against non-native English writers
The rapid adoption of generative language models has brought about
substantial advancements in digital communication, while simultaneously raising
concerns regarding the potential misuse of AI-generated content. Although
numerous detection methods have been proposed to differentiate between AI and
human-generated content, the fairness and robustness of these detectors remain
underexplored. In this study, we evaluate the performance of several
widely-used GPT detectors using writing samples from native and non-native
English writers. Our findings reveal that these detectors consistently
misclassify non-native English writing samples as AI-generated, whereas native
writing samples are accurately identified. Furthermore, we demonstrate that
simple prompting strategies can not only mitigate this bias but also
effectively bypass GPT detectors, suggesting that GPT detectors may
unintentionally penalize writers with constrained linguistic expressions. Our
results call for a broader conversation about the ethical implications of
deploying ChatGPT content detectors and caution against their use in evaluative
or educational settings, particularly when they may inadvertently penalize or
exclude non-native English speakers from the global discourse
The Next Generation Virgo cluster Survey. V. modelling the dynamics of M87 with the Made-to-Measure method
We study the dynamics of the giant elliptical galaxy M87 from the central to
the outermost regions with the made-to-measure (M2M) method. We use a new
catalogue of 922 globular cluster line-of- sight velocities extending to a
projected radius of 180 kpc (equivalent to 25 M87 effective radii), and SAURON
integral field unit data within the central 2.4 kpc. 263 globular clusters,
mainly located beyond 40 kpc, are newly observed by the Next Generation Virgo
Survey (NGVS). For the M2M modelling, the gravitational potential is taken as a
combination of a luminous matter potential with a constant stellar
mass-to-light ratio and a dark matter potential modelled as a logarithmic
potential. Our best dynamical model returns a stellar mass-to-light ratio in
the I band of M/LI = 6.0(+ -0.3) M_sun/L_sun with a dark matter potential scale
velocity of 591(+ -50) km/s and scale radius of 42(+ -10) kpc. We determine the
total mass of M87 within 180 kpc to be (1.5 + - 0.2) 10^13 M_sun. The mass
within 40 kpc is smaller than previous estimates determined using globular
cluster kinematics that did not extend beyond 45 kpc. With our new globular
cluster velocities at much larger radii, we see that globular clusters around
40 kpc show an anomalously large velocity dispersion which affected previous
results. The mass we derived is in good agreement with that inferred from ROSAT
X-ray observation out to 180 kpc. Within 30 kpc our mass is also consistent
with that inferred from Chandra and XMM-Newton X-ray observations, while within
120 kpc it is about 20% smaller. The model velocity dispersion anisotropy beta
parameter for the globular clusters in M87 is small, varying from -0.2 at the
centre to 0.2 at 40 kpc, and gradually decreasing to zero at 120 kpc.Comment: 20 pages, 16 figures, Accepted by Ap
State Transportation Improvement Program for Federal Fiscal Years 2011-2014
OBJECTIVES:To develop and validate a Taiwanese version of the Health Enhancement Lifestyle Profile (HELP-T) for community-dwelling older Taiwanese adults (≥ 55 years). METHODS:The original Health Enhancement Lifestyle Profile (HELP) is a 56-item self-report questionnaire measuring various aspects of health-related lifestyles in older adults. The standard cultural-adaptation procedure was used for questionnaire translation and modification. A field test was conducted for culturally specific item selection, rating-scale analysis, and psychometric validation of the HELP-T in a sample of 274 community-dwelling older adults via classical test theory. RESULTS:The 59-item HELP-T is culturally adapted from the original 56-item HELP. The original 6-point rating scale was modified to a 3-point scale for easy use by Taiwanese older adults. The HELP-T had good internal consistency (Cronbach's alpha = 0.82). The test-retest reliability for the total score was high (0.92), and moderate to high (range: 0.57-0.92) for subscales. The construct validity was supported by the significant correlations between each subscale and the total score (Spearman's rho = 0.41-0.67, p < 0.0001) and by the ability of the scores to significantly discriminate between participants with different levels of self-rated health (p = 0.0001). CONCLUSIONS:The HELP-T is a suitable clinical tool for assessing and monitoring lifestyle risk factors, establishing client-centered lifestyle intervention goals, and determining the outcomes of lifestyle interventions
The impacts of academic stress on college students' problematic smartphone use and Internet gaming disorder under the background of neijuan: Hierarchical regressions with mediational analysis on escape and coping motives
With sluggish economic growth in the post-pandemic era, the phenomenon “neijuan” becomes increasingly severe in many Asian countries like China. Neijuan refers to a hypercompetitive social environment wherein individuals involuntarily get involved in inhumane work or study hours, resulting in a considerable amount of tension and stress. Previous pathology research has shown that stress can trigger the overuse of Internet-based devices and services, which can subsequently lead to problematic smartphone use (PSU) and Internet gaming disorder (IGD). Provided college students are generally deemed one of the groups most susceptible to neijuan, limited attention has been given to the stimuli and the resultant psychological and behavioral ill-beings. Our study examined the impacts of academic stress on Chinese college students' PSU and IGD problems, with the inclusion of escape and coping motives as mediators. Based upon the results of hierarchical regressions and path analysis, we found that whereas academic stress increased IGD tendency mediated through escape and coping motives, excessive use of smartphone might have developed into a habitual behavior rather than effective escape and coping instruments. Demographic and academic characteristics, such as gender and whether studying at a prestigious institution, also exerted influences on college students' IGD intensity
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