1,271 research outputs found

    Epistasis

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    SEE ? The sky is a blue transparency; the sun shines straight through it with a plate of yellow sheen serving as the underlayer. And look how forked branches catch at the suggestion of gold, how it glitters down the bole and pours like buttermilk into the pool of green below..

    Central Limit Theorems for some Set Partition Statistics

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    We prove the conjectured limiting normality for the number of crossings of a uniformly chosen set partition of [n] = {1,2,...,n}. The arguments use a novel stochastic representation and are also used to prove central limit theorems for the dimension index and the number of levels

    Best possible densities of Dickson m-tuples, as a consequence of Zhang-Maynard-Tao

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    We determine for what proportion of integers hh one now knows that there are infinitely many prime pairs p, p+hp,\ p+h as a consequence of the Zhang-Maynard-Tao theorem. We consider the natural generalization of this to kk-tuples of integers, and we determine the limit of what can be deduced assuming only the Zhang-Maynard-Tao theorem.Comment: 9 pages. Final version. Some minor changes, Analytic Number Theory - In Honor of Helmut Maier's 60th Birthday, Springer, 201

    KOI-1003: A new spotted, eclipsing RS CVn binary in the Kepler field

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    Using the high-precision photometry from the Kepler space telescope, thousands of stars with stellar and planetary companions have been observed. The characterization of stars with companions is not always straightforward and can be contaminated by systematic and stellar influences on the light curves. Here, through a detailed analysis of starspots and eclipses, we identify KOI-1003 as a new, active RS CVn star---the first identified with data from Kepler. The Kepler light curve of this close binary system exhibits the system's primary transit, secondary eclipse, and starspot evolution of two persistent active longitudes. The near equality of the system's orbital and rotation periods indicates the orbit and primary star's rotation are nearly synchronized (Porb=8.360613±0.000003P_\mathrm{orb} = 8.360613\pm0.000003 days; Prot∼8.23P_\mathrm{rot} \sim 8.23 days). By assuming the secondary star is on the main sequence, we suggest the system consists of a 1.45−0.19+0.11 M⊙1.45^{+0.11}_{-0.19} \ M_\odot subgiant primary and a 0.59−0.04+0.03 M⊙0.59^{+0.03}_{-0.04} \ M_\odot main-sequence companion. Our work gives a distance of 4400±6004400 \pm 600 pc and an age of t=3.0+2.0−0.5t = 3.0^{-0.5}_{+2.0} Gyr, parameters which are discrepant with previous studies that included the star as a member of the open cluster NGC 6791.Comment: 21 pages, 19 figures, accepted to Ap

    Closed expressions for averages of set partition statistics

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    In studying the enumerative theory of super characters' of the group of upper triangular matrices over a finite field we found that the moments (mean, variance and higher moments) of novel statistics on set partitions have simple closed expressions as linear combinations of shifted bell numbers. It is shown here that families of other statistics have similar moments. The coefficients in the linear combinations are polynomials in nn. This allows exact enumeration of the moments for small nn to determine exact formulae for all nn

    Temperature-dependent transport in a sixfold degenerate two-dimensional electron system on a H-Si(111) surface

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    Low-field magnetotransport measurements on a high mobility (mu=110,000 cm^2/Vs) two-dimensional (2D) electron system on a H-terminated Si(111) surface reveal a sixfold valley degeneracy with a valley splitting <= 0.1 K. The zero-field resistivity rho_{xx} displays strong temperature dependence for 0.07 < T < 25 K as predicted for a system with high degeneracy and large mass. We present a method for using the low-field Hall coefficient to probe intervalley momentum transfer (valley drag). The relaxation rate is consistent with Fermi liquid theory, but a small residual drag as T->0 remains unexplained.Comment: 5 pages, 4 figures; revised and slightly shortened for publication

    Management of Peritonsillar Abscess Within a Local Emergency Department: A Quality Analysis Study.

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    OBJECTIVE: Peritonsillar abscess (PTA) is the most common deep space infection of the head and neck, affecting thousands of people annually with high treatment costs. The purpose of this project was to determine how in-network emergency departments (EDs) adhere to generally accepted guidelines regarding diagnosis and management of potential PTAs. METHODS: The authors performed a retrospective chart review to identify patients with PTA in five EDs in one year. Information pertaining to diagnostic tests, treatment, and airway status was also collected. Descriptive analysis was used to assess if EDs were consistent with generally accepted guidelines. RESULTS: Six hundred twenty-one patient records were identified and 140 were included in final analysis. Out of 140 patients, 71 were admitted for inpatient management and 23 were admitted for observation. Of the 46 patients diagnosed and discharged from the ED, 61% received a computerized tomography (CT) scan and only 39% had PTA drainage performed. Four (3%) patients received a point of care ultrasound and a CT scan and no patient received only an ultrasound. Out of all patients, 116/140 received a CT scan and 22 received drainage in the ED. The remainder of these patients either had drainage performed by an otolaryngologist or had no drainage performed. Of the 94 patients admitted for inpatient or observation, 84 received a CT scan and six received drainage by an ED physician. Only 62% of patients were given a penicillin derivative and 29% were given clindamycin, which has no Gram-negative coverage. CONCLUSION: One-third of PTA patients were managed within the ED, far less than similar studies. Of these, over 50% received a CT scan and less than 50% had PTA drainage. PTA drainage can improve patients\u27 symptoms and antibiotic effectiveness. The majority of patients were prescribed a penicillin derivative with or without another antibiotic
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