123 research outputs found
On the limitations of the use of solvable groups in Cayley graph cage constructions
AbstractA (k,g)-cage is a (connected) k-regular graph of girth g having smallest possible order. While many of the best known constructions of small k-regular graphs of girth g are known to be Cayley graphs, there appears to be no general theory of the relationship between the girth of a Cayley graph and the structure of the underlying group. We attempt to fill this gap by focusing on the girth of Cayley graphs of nilpotent and solvable groups, and present a series of results supporting the intuitive notion that the closer a group is to being abelian, the less suitable it is for constructing Cayley graphs of large girth. Specifically, we establish the existence of upper bounds on the girth of Cayley graphs with respect to the nilpotency class and/or the derived length of the underlying group, when this group is nilpotent or solvable, respectively
JWST Discovery of Dust Reservoirs in Nearby Type IIP Supernovae 2004et and 2017eaw
Supernova (SN) explosions have been sought for decades as a possible source
of dust in the Universe, providing the seeds of galaxies, stars, and planetary
systems. SN 1987A offers one of the most promising examples of significant SN
dust formation, but until the James Webb Space Telescope (JWST), instruments
have traditionally lacked the sensitivity at both late times (>1 yr
post-explosion) and longer wavelengths (i.e., >10 um) to detect analogous dust
reservoirs. Here we present JWST/MIRI observations of two historic Type IIP
SNe, 2004et and SN 2017eaw, at nearly 18 and 5 yr post-explosion, respectively.
We fit the spectral energy distributions as functions of dust mass and
temperature, from which we are able to constrain the dust geometry, origin, and
heating mechanism. We place a 90% confidence lower limit on the dust masses for
SNe 2004et and 2017eaw of >0.014 and >4e-4 M_sun, respectively. More dust may
exist at even colder temperatures or may be obscured by high optical depths. We
conclude dust formation in the ejecta to be the most plausible and consistent
scenario. The observed dust is radiatively heated to ~100-150 K by ongoing
shock interaction with the circumstellar medium. Regardless of the best fit or
heating mechanism adopted, the inferred dust mass for SN 2004et is the second
highest (next to SN 1987A) inferred dust mass in extragalactic SNe thus far,
promoting the prospect of SNe as potential significant sources of dust in the
Universe.Comment: 12 pages, 7 figures, submitting to MNRA
Genetic Drivers of Heterogeneity in Type 2 Diabetes Pathophysiology
Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes1,2 and molecular mechanisms that are often specific to cell type3,4. Here, to characterize the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study data from 2,535,601 individuals (39.7% not of European ancestry), including 428,452 cases of T2D. We identify 1,289 independent association signals at genome-wide significance (P \u3c 5 Ă 10-8) that map to 611 loci, of which 145 loci are, to our knowledge, previously unreported. We define eight non-overlapping clusters of T2D signals that are characterized by distinct profiles of cardiometabolic trait associations. These clusters are differentially enriched for cell-type-specific regions of open chromatin, including pancreatic islets, adipocytes, endothelial cells and enteroendocrine cells. We build cluster-specific partitioned polygenic scores5 in a further 279,552 individuals of diverse ancestry, including 30,288 cases of T2D, and test their association with T2D-related vascular outcomes. Cluster-specific partitioned polygenic scores are associated with coronary artery disease, peripheral artery disease and end-stage diabetic nephropathy across ancestry groups, highlighting the importance of obesity-related processes in the development of vascular outcomes. Our findings show the value of integrating multi-ancestry genome-wide association study data with single-cell epigenomics to disentangle the aetiological heterogeneity that drives the development and progression of T2D. This might offer a route to optimize global access to genetically informed diabetes care
Genetic drivers of heterogeneity in type 2 diabetes pathophysiology
Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes1,2 and molecular mechanisms that are often specific to cell type3,4. Here, to characterize the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study data from 2,535,601 individuals (39.7% not of European ancestry), including 428,452 cases of T2D. We identify 1,289 independent association signals at genome-wide significance (Pâ<â5âĂâ10-8) that map to 611 loci, of which 145 loci are, to our knowledge, previously unreported. We define eight non-overlapping clusters of T2D signals that are characterized by distinct profiles of cardiometabolic trait associations. These clusters are differentially enriched for cell-type-specific regions of open chromatin, including pancreatic islets, adipocytes, endothelial cells and enteroendocrine cells. We build cluster-specific partitioned polygenic scores5 in a further 279,552 individuals of diverse ancestry, including 30,288 cases of T2D, and test their association with T2D-related vascular outcomes. Cluster-specific partitioned polygenic scores are associated with coronary artery disease, peripheral artery disease and end-stage diabetic nephropathy across ancestry groups, highlighting the importance of obesity-related processes in the development of vascular outcomes. Our findings show the value of integrating multi-ancestry genome-wide association study data with single-cell epigenomics to disentangle the aetiological heterogeneity that drives the development and progression of T2D. This might offer a route to optimize global access to genetically informed diabetes care.</p
âSupposing that truth is a woman, what then?â The Lie Detector, The Love Machine and the Logic of Fantasy
One of the consequences of the public outcry over the 1929 St Valentineâs Day massacre was the establishment of a Scientific Crime Detection Laboratory at Northwestern University. The photogenic âLie Detector Manâ, Leonarde Keeler, was the Laboratoryâs poster boy and his instrument the jewel in the crown of forensic science. The press often depicted Keeler gazing at a female suspect attached to his âsweat boxâ; a galvanometer electrode in her hand, a sphygmomanometer cuff on her arm and a rubber pneumograph tube strapped across her breasts. Keelerâs fascination with the deceptive charms of the female body was one he shared with his fellow lie detector pioneers, all of whom met their wives â and in William Marstonâs case his mistress too â through their engagement with the instrument. Marston employed his own âLove Meterâ, as the press dubbed it, to prove that âbrunettes react far more violently to amatory stimuli than blondesâ. In this paper I draw on the psychoanalytic concepts of fantasy and pleasure to argue that the female body played a pivotal role in establishing the lie detectorâs reputation as an infallible and benign mechanical technology of truth
Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures
Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
The Practice of Japan in International Law 1961â1970. By Shigeru Oda and Hisashi Owada. [Tokyo: University of Tokyo Press. 1982. xxxii, 462 and (Index) 9 pp. Cased ÂŁ27·50 net.]
Nauru: Environmental Damage under International Trusteeship. By Christopher Weeramantry. [Melbourne: Oxford University Press. 1992. xx + 448 pp. ISBN 0â19â553289â9. ÂŁ45]
La protection de la souveraineté aérienne. By Ki-Gab Park. [Paris: A. Pédone. 1991. 403 pp. incl. bibliography and indexes. ISBN: 2-233-00216-4. FF.240]
- âŠ