2,296 research outputs found
Studying Gender in Conference Talks -- data from the 223rd meeting of the American Astronomical Society
We present a study on the gender balance, in speakers and attendees, at the
recent major astronomical conference, the American Astronomical Society meeting
223, in Washington, DC. We conducted an informal survey, yielding over 300
responses by volunteers at the meeting. Each response included gender data
about a single talk given at the meeting, recording the gender of the speaker
and all question-askers. In total, 225 individual AAS talks were sampled. We
analyze basic statistical properties of this sample. We find that the gender
ratio of the speakers closely matched the gender ratio of the conference
attendees. The audience asked an average of 2.8 questions per talk. Talks given
by women had a slightly higher number of questions asked (3.20.2) than
talks given by men (2.60.1). The most significant result from this study
is that while the gender ratio of speakers very closely mirrors that of
conference attendees, women are under-represented in the question-asker
category. We interpret this to be an age-effect, as senior scientists may be
more likely to ask questions, and are more commonly men. A strong dependence on
the gender of session chairs is found, whereby women ask disproportionately
fewer questions in sessions chaired by men. While our results point to laudable
progress in gender-balanced speaker selection, we believe future surveys of
this kind would help ensure that collaboration at such meetings is as inclusive
as possible.Comment: 4 pages, 5 figures. Comments welcome
Evidence of ongoing radial migration in NGC 6754: Azimuthal variations of the gas properties
Understanding the nature of spiral structure in disk galaxies is one of the
main, and still unsolved questions in galactic astronomy. However, theoretical
works are proposing new testable predictions whose detection is becoming
feasible with recent development in instrumentation. In particular, streaming
motions along spiral arms are expected to induce azimuthal variations in the
chemical composition of a galaxy at a given galactic radius. In this letter we
analyse the gas content in NGC 6754 with VLT/MUSE data to characterise its 2D
chemical composition and H line-of-sight velocity distribution. We find
that the trailing (leading) edge of the NGC 6754 spiral arms show signatures of
tangentially-slower, radially-outward (tangentially-faster, radially-inward)
streaming motions of metal-rich (poor) gas over a large range of radii. These
results show direct evidence of gas radial migration for the first time. We
compare our results with the gas behaviour in a -body disk simulation
showing spiral morphological features rotating with a similar speed as the gas
at every radius, in good agreement with the observed trend. This indicates that
the spiral arm features in NGC 6754 may be transient and rotate similarly as
the gas does at a large range of radii.Comment: 8 pages, 4 figures, accepted for publication in ApJL 2016 September
2
Renormalization Group Study of the soliton mass on the (lambda Phi^4)_{1+1} lattice model
We compute, on the model on the lattice, the soliton
mass by means of two very different numerical methods. First, we make use of a
``creation operator'' formalism, measuring the decay of a certain correlation
function. On the other hand we measure the shift of the vacuum energy between
the symmetric and the antiperiodic systems. The obtained results are fully
compatible.
We compute the continuum limit of the mass from the perturbative
Renormalization Group equations. Special attention is paid to ensure that we
are working on the scaling region, where physical quantities remain unchanged
along any Renormalization Group Trajectory. We compare the continuum value of
the soliton mass with its perturbative value up to one loop calculation. Both
quantities show a quite satisfactory agreement. The first is slightly bigger
than the perturbative one; this may be due to the contributions of higher order
corrections.Comment: 19 pages, preprint DFTUZ/93/0
Economics of education research: a review and future prospects
In this paper we offer an appraisal of the economics of education research area, charting its history as a field and discussing the ways in which economists have contributed both to education research and to education policy-making. In particular, we highlight the theoretical and methodological contributions that economists have made to the field of education during the last 50 years. Despite the success of the economics of education as a field of inquiry, we argue that some of the contributions made by economists could be limited if the economics of education is seen as quite distinct from the other disciplines working in the field of education. In these areas of common interest, economists need to work side by side with the other major disciplines in the field of education if their contribution to the field is to be maximised, particularly in terms of applying improved methodology. We conclude that the study of education acquisition and its economic and social impact in the economics of education research area is very likely to remain a fertile research ground. Acknowledgement
Chromosome conformation maps in fission yeast reveal cell cycle dependent sub nuclear structure
Successful progression through the cell cycle requires spatial and temporal regulation of gene transcript levels and the number, positions and condensation levels of chromosomes. Here we present a high resolution survey of genome interactions in Schizosaccharomyces pombe using synchronized cells to investigate cell cycle dependent changes in genome organization and transcription. Cell cycle dependent interactions were captured between and within S. pombe chromosomes. Known features of genome organization (e.g. the clustering of telomeres and retrotransposon long terminal repeats (LTRs)) were observed throughout the cell cycle. There were clear correlations between transcript levels and chromosomal interactions between genes, consistent with a role for interactions in transcriptional regulation at specific stages of the cell cycle. In silico reconstructions of the chromosome organization within the S. pombe nuclei were made by polymer modeling. These models suggest that groups of genes with high and low, or differentially regulated transcript levels have preferred positions within the S. pombe nucleus. We conclude that the S. pombe nucleus is spatially divided into functional sub-nuclear domains that correlate with gene activity. The observation that chromosomal interactions are maintained even when chromosomes are fully condensed in M phase implicates genome organization in epigenetic inheritance and bookmarking
Dual superconductivity in the SU(2) pure gauge vacuum: a lattice study
We investigate the dual superconductivity hypothesis in pure SU(2) lattice
gauge theory. We focus on the dual Meissner effect by analyzing the
distribution of the color fields due to a static quark-antiquark pair. We find
evidence of the dual Meissner effect both in the maximally Abelian gauge and
without gauge fixing. We measure the London penetration length. Our results
suggest that the London penetration length is a physical gauge-invariant
quantity. We put out a simple relation between the penetration length and the
square root of the string tension. We find that our extimation is quite close
to the extrapolated continuum limit available in the literature. A remarkable
consequence of our study is that an effective Abelian theory can account for
the long range properties of the SU(2) confining vacuum.Comment: 38 pages, uuencoded compressed (using GNU's gzip) tar file containing
1 LaTeX2e file (to be processed 3 times) + 16 encapsulated Postscript
figures. A full Postscript version of this paper is available at
http://www.ba.infn.it/disk$gruppo_4/cosmai/www/papers/195-95.P
Black Holes, Mergers, and the Entropy Budget of the Universe
Vast amounts of entropy are produced in black hole formation, and the amount
of entropy stored in supermassive black holes at the centers of galaxies is now
much greater than the entropy free in the rest of the universe. Either mergers
involved in forming supermassive black holes are rare,or the holes must be very
efficient at capturing nearly all the entropy generated in the process.
We argue that this information can be used to constrain supermassive black
hole production, and may eventually provide a check on numerical results for
mergers involving black holes
Hyperon Polarization in the Constituent Quark Model
We consider mechanism for hyperon polarization in inclusive production. The
main role belongs to the orbital angular momentum and polarization of the
strange quark-antiquark pairs in the internal structure of the constituent
quarks. We consider a nucleon as a core consisting of the constituent quarks
embedded into quark condensate. The nonperturbative hadron structure is based
on the results of chiral quark models.Comment: 14 pages, LaTeX, 2 Figures, References adde
The globular cluster system of the Auriga simulations
We investigate whether the galaxy and star formation model used for the
Auriga simulations can produce a realistic globular cluster (GC) population. We
compare statistics of GC candidate star particles in the Auriga haloes with
catalogues of the Milky Way (MW) and Andromeda (M31) GC populations. We find
that the Auriga simulations do produce sufficient stellar mass for GC
candidates at radii and metallicities that are typical for the MW GC system
(GCS). We also find varying mass-ratios of the simulated GC candidates relative
to the observed mass in the MW and M31 GC systems for different bins of
galactocentric radius-metallicity (r -[Fe/H]). Overall, the
Auriga simulations produce GC candidates with higher metallicities than the MW
and M31 GCS and they are found at larger radii than observed. The Auriga
simulations would require bound cluster formation efficiencies higher than ten
percent for the metal-poor GC candidates, and those within the Solar radius
should experience negligible destruction rates to be consistent with
observations. GC candidates in the outer halo, on the other hand, should either
have low formation efficiencies, or experience high mass loss for the Auriga
simulations to produce a GCS that is consistent with that of the MW or M31.
Finally, the scatter in the metallicity as well as in the radial distribution
between different Auriga runs is considerably smaller than the differences
between that of the MW and M31 GCSs. The Auriga model is unlikely to give rise
to a GCS that can be consistent with both galaxies.Comment: Accepted by MNRAS 2020 May 15. Received 2020 May 14; in original form
2019 September
- …