178 research outputs found
Personal Anagrams
The appeal in constructing anagrams lies in the balance between the extreme confinement of working with a fixed set of letters and the tremendous room for exploration afforded by all the permutations of those letters. If I were required to write a poem, without any restrictions on the form or content, my brain would quickly enter a state of paralysis; for without constraints on the assignment, the possibilities are infinite - and overwhelming
Anagrams by Hand
What\u27s so interesting about anagrams? They\u27re just rearrangements of letters. Couldn\u27t\u27 a computer crank out a million of them in the time it would take a human to sharpen his pencil? What if a computer and a human tried to anagram the same phrase? Wouldn\u27t they both come up with the same set of good anagrams, given enough time
The CatWISE Preliminary Catalog: Motions from and Data
CatWISE is a program to catalog sources selected from combined
and all-sky survey data at 3.4 and 4.6 m (W1 and W2). The
CatWISE Preliminary Catalog consists of 900,849,014 sources measured in data
collected from 2010 to 2016. This dataset represents four times as many
exposures and spans over ten times as large a time baseline as that used for
the AllWISE Catalog. CatWISE adapts AllWISE software to measure the sources in
coadded images created from six-month subsets of these data, each representing
one coverage of the inertial sky, or epoch. The catalog includes the measured
motion of sources in 8 epochs over the 6.5 year span of the data. From
comparison to , the SNR=5 limits in magnitudes in the Vega
system are W1=17.67 and W2=16.47, compared to W1=16.96 and W2=16.02 for
AllWISE. From comparison to , CatWISE positions have typical
accuracies of 50 mas for stars at W1=10 mag and 275 mas for stars at W1=15.5
mag. Proper motions have typical accuracies of 10 mas yr and 30 mas
yr for stars with these brightnesses, an order of magnitude better than
from AllWISE. The catalog is available in the WISE/NEOWISE Enhanced and
Contributed Products area of the NASA/IPAC Infrared Science Archive.Comment: 53 pages, 20 figures, 5 tables. Accepted by ApJ
The CatWISE2020 Catalog
The CatWISE2020 Catalog consists of 1,890,715,640 sources over the entire sky
selected from WISE and NEOWISE survey data at 3.4 and 4.6 m (W1 and W2)
collected from 2010 Jan. 7 to 2018 Dec. 13. This dataset adds two years to that
used for the CatWISE Preliminary Catalog (Eisenhardt et al., 2020), bringing
the total to six times as many exposures spanning over sixteen times as large a
time baseline as the AllWISE catalog. The other major change from the CatWISE
Preliminary Catalog is that the detection list for the CatWISE2020 Catalog was
generated using (Schlafly et al. 2019), while the CatWISE
Preliminary Catalog used the detection software used for AllWISE. These two
factors result in roughly twice as many sources in the CatWISE2020 Catalog. The
scatter with respect to photometry at faint magnitudes in the
COSMOS field, which is out of the Galactic plane and at low ecliptic latitude
(corresponding to lower WISE coverage depth) is similar to that for the CatWISE
Preliminary Catalog. The 90% completeness depth for the CatWISE2020 Catalog is
at W1=17.7 mag and W2=17.5 mag, 1.7 mag deeper than in the CatWISE Preliminary
Catalog. From comparison to , CatWISE2020 motions are accurate at
the 20 mas yr level for W115 mag sources, and at the mas
yr level for W117 mag sources. This level of precision represents
a 12 improvement over AllWISE. The CatWISE catalogs are available in
the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC
Infrared Science Archive.Comment: 27 pages, 24 figure, 2 tables. Accepted for publication in ApJS.
arXiv admin note: text overlap with arXiv:1908.0890
Revision of AMBER Torsional Parameters for RNA Improves Free Energy Predictions for Tetramer Duplexes with GC and iGiC Base Pairs
All-atom force fields are important for predicting thermodynamic, structural, and dynamic properties of RNA. In this paper, results are reported for thermodynamic integration calculations of free energy differences of duplex formation when CG pairs in the RNA duplexes r(CCGG)2, r(GGCC)2, r(GCGC)2, and r(CGCG)2 are replaced by isocytidine–isoguanosine (iCiG) pairs. Agreement with experiment was improved when ε/ζ, α/γ, β, and χ torsional parameters in the AMBER99 force field were revised on the basis of quantum mechanical calculations. The revised force field, AMBER99TOR, brings free energy difference predictions to within 1.3, 1.4, 2.3, and 2.6 kcal/mol at 300 K, respectively, compared to experimental results for the thermodynamic cycles of CCGG → iCiCiGiG, GGCC → iGiGiCiC, GCGC → iGiCiGiC, and CGCG → iCiGiCiG. In contrast, unmodified AMBER99 predictions for GGCC → iGiGiCiC and GCGC → iGiCiGiC differ from experiment by 11.7 and 12.6 kcal/mol, respectively. In order to test the dynamic stability of the above duplexes with AMBER99TOR, four individual 50 ns molecular dynamics (MD) simulations in explicit solvent were run. All except r(CCGG)2 retained A-form conformation for ≥82% of the time. This is consistent with NMR spectra of r(iGiGiCiC)2, which reveal an A-form conformation. In MD simulations, r(CCGG)2 retained A-form conformation 52% of the time, suggesting that its terminal base pairs may fray. The results indicate that revised backbone parameters improve predictions of RNA properties and that comparisons to measured sequence dependent thermodynamics provide useful benchmarks for testing force fields and computational methods
CWISEP J193518.59–154620.3: An Extremely Cold Brown Dwarf in the Solar Neighborhood Discovered with CatWISE
We present the discovery of an extremely cold, nearby brown dwarf in the solar neighborhood, found in the CatWISE catalog. Photometric follow-up with Spitzer reveals that the object, CWISEP J193518.59–154620.3, has ch1–ch2 = 3.24 ± 0.31 mag, making it one of the reddest brown dwarfs known. Using the Spitzer photometry and the polynomial relations from Kirkpatrick et al. we estimate an effective temperature in the ~270–360 K range, and a distance estimate in the 5.6–10.9 pc range. We combined the WISE, NEOWISE, and Spitzer data to measure a proper motion of μ_α cos δ = 337±69 mas yr^(−1), μ_δ = −50 ± 97 mas yr^(−1), which implies a relatively low tangential velocity in the range 7–22 km s^(−1)
Benchmarking AMBER Force Fields for RNA: Comparisons to NMR Spectra for Single-Stranded r(GACC) Are Improved by Revised χ Torsions
Intraneuronal Aβ immunoreactivity is not a predictor of brain amyloidosis-β or neurofibrillary degeneration
Amyloid β (Aβ) immunoreactivity in neurons was examined in brains of 32 control subjects, 31 people with Down syndrome, and 36 patients with sporadic Alzheimer’s disease to determine if intraneuronal Aβ immunoreactivity is an early manifestation of Alzheimer-type pathology leading to fibrillar plaque formation and/or neurofibrillary degeneration. The appearance of Aβ immunoreactivity in neurons in infants and stable neuron-type specific Aβ immunoreactivity in a majority of brain structures during late childhood, adulthood, and normal aging does not support this hypothesis. The absence or detection of only traces of reaction with antibodies against 4–13 aa and 8–17 aa of Aβ in neurons indicated that intraneuronal Aβ was mainly a product of α- and γ-secretases (Aβ(17–40/42)). The presence of N-terminally truncated Aβ(17–40) and Aβ(17–42) in the control brains was confirmed by Western blotting and the identity of Aβ(17–40) was confirmed by mass spectrometry. The prevalence of products of α- and γ -secretases in neurons and β- and γ-secretases in plaques argues against major contribution of Aβ-immunopositive material detected in neuronal soma to amyloid deposit in plaques. The strongest intraneuronal Aβ(17–42) immunoreactivity was observed in structures with low susceptibility to fibrillar Aβ deposition, neurofibrillary degeneration, and neuronal loss compared to areas more vulnerable to Alzheimer-type pathology. These observations indicate that the intraneuronal Aβ immunoreactivity detected in this study is not a predictor of brain amyloidosis or neurofibrillary degeneration. The constant level of Aβ immunoreactivity in structures free from neuronal pathology during essentially the entire life span suggests that intraneuronal amino-terminally truncated Aβ represents a product of normal neuronal metabolism
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Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis
Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1×10-12) and x-linked CLDN2 (p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07
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