1,222 research outputs found
New evidence for Green's conjecture on syzygies of canonical curves
We prove that two weakened forms of Green's conjectures for canonical curves
are equivalent when the genus is odd.Comment: Tex-type: LaTe
BEC-BCS Crossover in Neutron Matter with Renormalization Group based Effective Interactions
We study pure neutron matter in the BEC-BCS crossover regime using
renormalization group based low-momentum interactions within the
Nozi\`eres-Schmitt-Rink framework. This is an attempt to go beyond the mean
field description for low-density matter. We work in the basis of so-called
Weinberg eigenvectors where the operator is diagonal, which proves to be
an excellent choice that allows one to use non-local interactions in a very
convenient way. We study the importance of correlations as a function of
density. We notice that there is a significant reduction of the BCS critical
temperature at low-densities as the neutron matter approaches the unitary
limit.Comment: 10 pages and 8 figures, Figs 6 and 7 now includes higher cut-offs,
discussion of the cut-off dependence improved, new Summary and Outlook
section and new references adde
New constraints on the Pion EM form factor using Pi'(-Q^2)
We study the constraints arising on the expansion parameters c and d of the
Pion electromagnetic form factor from the inclusion of pure space-like data and
the phase of time-like data along with one space-like datum, using as input the
first derivative of the QCD polarization amplitude Pi'(-Q^2). These constraints
when combined with other analyses, provide a valuable check on a determination
of c due to Guo et al. and on our previous work where pionic contribution to
the (g-2) of the muon was used as the input. This work further illustrates the
power of analyticity techniques in form factor analysis.Comment: 8 pages latex, uses EPJA style files, contains 12 figures; replaced
with version accepted for publication in EPJA, minor typos corrected,
discussion improved, reference adde
Interactions between species introduce spurious associations in microbiome studies
Microbiota contribute to many dimensions of host phenotype, including
disease. To link specific microbes to specific phenotypes, microbiome-wide
association studies compare microbial abundances between two groups of samples.
Abundance differences, however, reflect not only direct associations with the
phenotype, but also indirect effects due to microbial interactions. We found
that microbial interactions could easily generate a large number of spurious
associations that provide no mechanistic insight. Using techniques from
statistical physics, we developed a method to remove indirect associations and
applied it to the largest dataset on pediatric inflammatory bowel disease. Our
method corrected the inflation of p-values in standard association tests and
showed that only a small subset of associations is directly linked to the
disease. Direct associations had a much higher accuracy in separating cases
from controls and pointed to immunomodulation, butyrate production, and the
brain-gut axis as important factors in the inflammatory bowel disease.Comment: 4 main text figures, 15 supplementary figures (i.e appendix) and 6
supplementary tables. Overall 49 pages including reference
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