8,783 research outputs found
CO line emission from galaxies in the Epoch of Reionization
We study the CO line luminosity (), the shape of the CO Spectral
Line Energy Distribution (SLED), and the value of the CO-to-
conversion factor in galaxies in the Epoch of Reionization (EoR). To this aim,
we construct a model that simultaneously takes into account the radiative
transfer and the clumpy structure of giant molecular clouds (GMCs) where the CO
lines are excited. We then use it to post-process state-of-the-art zoomed, high
resolution (), cosmological simulation of a main-sequence
(, ) galaxy, "Alth{\ae}a", at . We find that the CO emission
traces the inner molecular disk () of Alth{\ae}a with
the peak of the CO surface brightness co-located with that of the [CII] 158 emission. Its is comparable
to that observed in local galaxies with similar stellar mass. The high
() gas surface density in
Alth{\ae}a, its large Mach number (\mach), and the warm kinetic
temperature () of GMCs yield a CO SLED peaked at the
CO(7-6) transition, i.e. at relatively high-, and a CO-to-
conversion factor lower than that of the Milky Way. The ALMA observing time
required to detect (resolve) at 5 the CO(7-6) line from galaxies
similar to Alth{\ae}a is h ( h).Comment: 16 pages, 14 figures, accepted for publication in MNRA
Recommended from our members
Beach impact study, Padre Island National Seashore
Prepared for Office of Natural Science, Southwest Region, National Park Service, under contract CX70005044830 April 1976Vegetative differences between heavily and very lightly trafficked beaches show that more beach traffic correlates with quantitative decreases in variety and density of plants and with declines of grasses relative to forbs. The vegetated portions of all beaches continue to grow in volume. However, this is at the expense of the more seaward (more trafficked) parts of the beaches and has lead to overall loss of total beach volume except where vehicular traffic is prohibited. The very lightly trafficked beach is the only study site wherein the entire beach to mean sea level has grown. The effect of these trends on resistance to storm surge erosion remains to be tested.Marine Scienc
Scanning transmission type imaging and analysis (EDX) of protein supported metallic nanoparticles
Ventromedial Prefrontal and Anterior Cingulate Cortex Adopt Choice and Default Reference Frames during Sequential Multi-Alternative Choice
Although damage to the medial frontal cortex causes profound decision-making impairments, it has been difficult to pinpoint the relative
contributions of key anatomical subdivisions. Here we use function magnetic resonance imaging to examine the contributions of human
ventromedial prefrontal cortex (vmPFC) and dorsal anterior cingulate cortex (dACC) during sequential choices between multiple alternatives—
two key features of choices made in ecological settings. By carefully constructing options whose current value at any given
decision was dissociable from their longer term value, we were able to examine choices in current and long-term frames of reference. We
present evidence showing that activity at choice and feedback in vmPFC and dACC was tied to the current choice and the best long-term
option, respectively. vmPFC, mid-cingulate, and posterior cingulate cortex encoded the relative value between the chosen and next best
option at each sequential decision, whereas dACC encoded the relative value of adapting choices from the option with the highest value in
the longer term. Furthermore, at feedback we identify temporally dissociable effects that predict repetition of the current choice and
adaptation away from the long-term best option in vmPFC and dACC, respectively. These functional dissociations at choice and feedback
suggest that sequential choices are subject to competing cortical mechanisms
The role of sexual orientation in the relationships between body perception, body weight dissatisfaction, physical comparison, and eating psychopathology in the cisgender population
Purpose: Body weight dissatisfaction (BWD) and visual body perception are specific aspects that can influence the own body image, and that can concur with the development or the maintenance of specific psychopathological dimensions of different psychiatric disorders. The sexual orientation is a fundamental but understudied aspect in this field, and, for this reason, the purpose of this study is to improve knowledge about the relationships among BWD, visual body size-perception, and sexual orientation. Methods: A total of 1033 individuals participated in an online survey. Physical comparison, depression, and self-esteem was evaluated, as well as sexual orientation and the presence of an eating disorder. A Figure Rating Scale was used to assess different valences of body weight, and mediation analyses were performed to investigated specific relationships between psychological aspects. Results: Bisexual women and gay men reported significantly higher BWD than other groups (p < 0.001); instead, higher body misperception was present in gay men (p = 0.001). Physical appearance comparison mediated the effect of sexual orientation in both BWD and perceptual distortion. No difference emerged between women with a history of eating disorders and without, as regards the value of body weight attributed to attractiveness, health, and presence on social media. Conclusion: This study contributes to understanding the relationship between sexual orientations and body image representation and evaluation. Physical appearance comparisons should be considered as critical psychological factors that can improve and affect well-being. The impact on subjects with high levels of eating concerns is also discussed. Level of evidence: Level III: case\u2013control analytic study
Arctic sea ice area changes in CMIP3 and CMIP5 climate models’ ensembles
The shrinking Arctic sea ice cover observed during the last decades is probably the clearest manifestation of ongoing climate change. While climate models in general reproduce the sea ice retreat in the Arctic during the 20th century
and simulate further sea ice area loss during the 21st century in response to anthropogenic forcing, the models suffer from large biases and the results exhibit considerable spread. Here, we compare results from the two last generations of climate models, CMIP3 and CMIP5, with respect to total and regional Arctic sea ice change. Different characteristics of sea ice area (SIA) in March and September have been analysed for the Entire Arctic, Central Arctic and Barents Sea. Further, the sensitivity of SIA to changes in Northern Hemisphere (NH) temperature is investigated and dynamical links between SIA and some atmospheric variability modes are assessed.
CMIP3 (SRES A1B) and CMIP5 (RCP8.5) models not only simulate a coherent decline of the Arctic SIA but also depict consistent changes in the SIA seasonal cycle. The spatial patterns of SIC variability improve in CMIP5 ensemble, most noticeably in summer when compared to HadISST1 data. A better simulation of summer SIA in the Entire Arctic by CMIP5 models is accompanied by a slightly increased bias for winter season in comparison to CMIP3 ensemble. SIA in the Barents Sea is strongly overestimated by the majority of CMIP3 and CMIP5 models, and projected SIA changes are characterized by a high uncertainty. Both CMIP ensembles depict a significant link
between the SIA and NH temperature changes indicating that a part of inter-ensemble SIA spread comes from different temperature sensitivity to anthropogenic forcing. The results suggest that, in general, a sensitivity of SIA to external forcing is enhanced in CMIP5 models. Arctic SIA interannual variability in the end of the 20th century is on average well simulated by both ensembles. To the end of the 21st century, September variability is strongly reduced in CMIP5 models under RCP8.5 scenario, whereas variability changes in CMIP3 and in both ensembles in March are relatively small. The majority of models in both CMIP ensembles demonstrate an ability to capture a negative correlation of interannual SIA variations in the Barents Sea with North Atlantic Oscillation and sea level pressure gradient in the western Barents Sea opening serving as an index of oceanic inflow to the Sea
Fuzzy Fibers: Uncertainty in dMRI Tractography
Fiber tracking based on diffusion weighted Magnetic Resonance Imaging (dMRI)
allows for noninvasive reconstruction of fiber bundles in the human brain. In
this chapter, we discuss sources of error and uncertainty in this technique,
and review strategies that afford a more reliable interpretation of the
results. This includes methods for computing and rendering probabilistic
tractograms, which estimate precision in the face of measurement noise and
artifacts. However, we also address aspects that have received less attention
so far, such as model selection, partial voluming, and the impact of
parameters, both in preprocessing and in fiber tracking itself. We conclude by
giving impulses for future research
Weak Long-Ranged Casimir Attraction in Colloidal Crystals
We investigate the influence of geometric confinement on the free energy of
an idealized model for charge-stabilized colloidal suspensions. The mean-field
Poisson-Boltzmann formulation for this system predicts pure repulsion among
macroionic colloidal spheres. Fluctuations in the simple ions' distribution
provide a mechanism for the macroions to attract each other at large
separations. Although this Casimir interaction is long-ranged, it is too weak
to influence colloidal crystals' dynamics.Comment: 5 pages 2 figures ReVTe
- …