254 research outputs found
Indiana High Accuracy Reference Network (HARN) Final Report
This report has three main areas of interest. First, a brief discussion on the need for the Indiana HARN and why this was an important task. Second, a summary of the details surrounding the Indiana HARN survey. Finally, the station description of the HARN point in your county is attached with a map of the general area surrounding this point. We have also included a discussion on monument preservation with tips on how keep the high accuracies associated with your point(s). Also, a section is included on how the HARN is being used in Indiana with a few success stories
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Genetic Variation in the Base Excision Repair Pathway, Environmental Risk Factors, and Colorectal Adenoma Risk
Cigarette smoking, high alcohol intake, and low dietary folate levels are risk factors for colorectal adenomas. Oxidative damage caused by these three factors can be repaired through the base excision repair pathway (BER). We hypothesized that genetic variation in BER might modify colorectal adenoma risk. In a sigmoidoscopy-based study, we examined associations between 182 haplotype tagging SNPs in 14 BER genes, and colorectal adenoma risk, and examined their potential role as modifiers of the effect cigarette smoking, alcohol intake, and dietary folate levels. Among all individuals, no statistically significant associations between BER SNPs and adenoma risk persisted after correction for multiple comparisons. However, among Asian-Pacific Islanders we observed two SNPs in FEN1 and one in NTHL1, and among African-Americans one SNP in APEX1 that were associated with colorectal adenoma risk. Significant associations were also observed between SNPs in the NEIL2 gene and rectal adenoma risk. Three SNPS modified the effect of smoking (MUTYH interaction p = 0.002; OGG1 interaction p = 0.013); FEN1 interaction p = 0.013)), one SNP in LIG3 modified the effect of alcohol consumption (interaction p = 0.024) and two SNPs in LIG3 modified the effect of dietary folate (interaction p = 0.001 and p = 0.08) on colorectal adenoma risk. These findings support a role for genetic variants in the BER pathway as potential modifiers of colorectal adenoma risk. Our findings strengthen the role of oxidative damage induced by key lifestyle and dietary risk factors in colorectal adenoma formation
BRCA1 is required for maintenance of phospho-Chk1 and G<sub>2</sub>/M arrest during DNA cross-link repair in DT40 cells
The Fanconi anemia DNA repair pathway is pivotal for the efficient repair of DNA interstrand cross-links. Here, we show that FA-defective (Fancc(-)) DT40 cells arrest in G(2) phase following cross-link damage and trigger apoptosis. Strikingly, cell death was reduced in Fancc(-) cells by additional deletion of the BRCA1 tumor suppressor, resulting in elevated clonogenic survival. Increased resistance to cross-link damage was not due to loss of toxic BRCA1-mediated homologous recombination but rather through the loss of a G(2) checkpoint. This proapoptotic role also required the BRCA1-A complex member ABRAXAS (FAM175A). Finally, we show that BRCA1 promotes G(2) arrest and cell death by prolonging phosphorylation of Chk1 on serine 345 after DNA damage to sustain arrest. Our data imply that DNA-induced cross-link death in cells defective in the FA pathway is dependent on the ability of BRCA1 to prolong cell cycle arrest in G(2) phase
Longitudinal research: A panel discussion on conceptual issues, research design, and statistical techniques
Stellar Diameters and Temperatures II. Main Sequence K & M Stars
We present interferometric diameter measurements of 21 K- and M- dwarfs made
with the CHARA Array. This sample is enhanced by literature radii measurements
to form a data set of 33 K-M dwarfs with diameters measured to better than 5%.
For all 33 stars, we compute absolute luminosities, linear radii, and effective
temperatures (Teff). We develop empirical relations for \simK0 to M4 main-
sequence stars between the stellar Teff, radius, and luminosity to broad-band
color indices and metallicity. These relations are valid for metallicities
between [Fe/H] = -0.5 and +0.1 dex, and are accurate to ~2%, ~5%, and ~4% for
Teff, radius, and luminosity, respectively. Our results show that it is
necessary to use metallicity dependent transformations to convert colors into
stellar Teffs, radii, and luminosities. We find no sensitivity to metallicity
on relations between global stellar properties, e.g., Teff-radius and
Teff-luminosity. Robust examinations of single star Teffs and radii compared to
evolutionary model predictions on the luminosity-Teff and luminosity-radius
planes reveals that models overestimate the Teffs of stars with Teff < 5000 K
by ~3%, and underestimate the radii of stars with radii < 0.7 R\odot by ~5%.
These conclusions additionally suggest that the models overestimate the effects
that the stellar metallicity may have on the astrophysical properties of an
object. By comparing the interferometrically measured radii for single stars to
those of eclipsing binaries, we find that single and binary star radii are
consistent. However, the literature Teffs for binary stars are systematically
lower compared to Teffs of single stars by ~ 200 to 300 K. Lastly, we present a
empirically determined HR diagram for a total of 74 nearby, main-sequence, A-
to M-type stars, and define regions of habitability for the potential existence
of sub-stellar mass companions in each system. [abridged]Comment: 73 pages, 12 Tables, 18 Figures. Accepted for publication in The
Astrophysical Journa
A Consistency Test of Spectroscopic Gravities for Late-Type Stars
Chemical analyses of late-type stars are usually carried out following the
classical recipe: LTE line formation and homogeneous, plane-parallel,
flux-constant, and LTE model atmospheres. We review different results in the
literature that have suggested significant inconsistencies in the spectroscopic
analyses, pointing out the difficulties in deriving independent estimates of
the stellar fundamental parameters and hence,detecting systematic errors.
The trigonometric parallaxes measured by the HIPPARCOS mission provide
accurate appraisals of the stellar surface gravity for nearby stars, which are
used here to check the gravities obtained from the photospheric iron ionization
balance. We find an approximate agreement for stars in the metallicity range -1
<= [Fe/H] <= 0, but the comparison shows that the differences between the
spectroscopic and trigonometric gravities decrease towards lower metallicities
for more metal-deficient dwarfs (-2.5 <= [Fe/H] <= -1.0), which casts a shadow
upon the abundance analyses for extreme metal-poor stars that make use of the
ionization equilibrium to constrain the gravity. The comparison with the
strong-line gravities derived by Edvardsson (1988) and Fuhrmann (1998a)
confirms that this method provides systematically larger gravities than the
ionization balance. The strong-line gravities get closer to the physical ones
for the stars analyzed by Fuhrmann, but they are even further away than the
iron ionization gravities for the stars of lower gravities in Edvardsson's
sample. The confrontation of the deviations of the iron ionization gravities in
metal-poor stars reported here with departures from the excitation balance
found in the literature, show that they are likely to be induced by the same
physical mechanism(s).Comment: AAS LaTeX v4.0, 35 pages, 10 PostScript files; to appear in The
Astrophysical Journa
Tidal Signatures in the Faintest Milky Way Satellites: The Detailed Properties of Leo V, Pisces II and Canes Venatici II
We present deep wide-field photometry of three recently discovered faint
Milky Way satellites: Leo V, Pisces II, and Canes Venatici II. Our main goals
are to study the structure and star formation history of these dwarfs; we also
search for signs of tidal disturbance. The three satellites have similar
half-light radii ( pc) but a wide range of ellipticities. Both Leo
V and CVn II show hints of stream-like overdensities at large radii. An
analysis of the satellite color-magnitude diagrams shows that all three objects
are old ( 10 Gyr) and metal-poor ([Fe/H] ), though neither the
models nor the data have sufficient precision to assess when the satellites
formed with respect to cosmic reionization. The lack of an observed younger
stellar population (\la 10 Gyr) possibly sets them apart from the other
satellites at Galactocentric distances \ga 150 kpc. We present a new
compilation of structural data for all Milky Way satellite galaxies and use it
to compare the properties of classical dwarfs to the ultra-faints. The
ellipticity distribution of the two groups is consistent at the
2- level. However, the faintest satellites tend to be more
aligned toward the Galactic center, and those satellites with the highest
ellipticity (\ga 0.4) have orientations () in the range
. This latter
observation is in rough agreement with predictions from simulations of dwarf
galaxies that have lost a significant fraction of their dark matter halos and
are being tidally stripped.Comment: 25 pages, 7 figures, ApJ accepted; version updated to match ApJ
accepte
Glucagonoma Masquerading as a Mucinous Cancer of the Ovary: Lessons from Cell Biology
High-grade mucinous ovarian cancer (HGMOC) is often a misnomer as the majority of cases are metastatic disease with a gastro-intestinal origin. The standard platinum-based ovarian cancer (OC) chemotherapy regimens are often ineffective, and there are insufficient data to support the use of colorectal cancer (CRC) chemotherapy regimens due to the rarity of HGMOC. We described a cohort of four consecutive suspected HGMOC cases treated at the Royal Womenâs Hospital, Melbourne in 2012. Two cases were treated as primary MOC, whereas the other two were considered to be metastatic CRC based on histopathological and clinical evidence. From the RNAseq analysis, we identified two cases of HGMOC whose gene expression profiles were consistent with mucinous epithelial OC, one case that was treated as metastatic CRC with gene expression profile correlated with CRC and one case with neuroendocrine (NET) gene expression features. Interestingly, glucagon was over-expressed in this tumor that was subsequently confirmed by immunohistochemistry. These findings suggest a rare glucagonoma-like NET appendiceal tumor that had metastasized to the surface of ovary and were unresponsive to CRC chemotherapy regimens. In summary, a carefully curated panel of expression markers and selected functional genomics could provide diagnosis and treatment guidance for patients with possible HGMOC
The Fifth Data Release of the Sloan Digital Sky Survey
This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky
Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and
represents the completion of the SDSS-I project (whose successor, SDSS-II will
continue through mid-2008). It includes five-band photometric data for 217
million objects selected over 8000 square degrees, and 1,048,960 spectra of
galaxies, quasars, and stars selected from 5713 square degrees of that imaging
data. These numbers represent a roughly 20% increment over those of the Fourth
Data Release; all the data from previous data releases are included in the
present release. In addition to "standard" SDSS observations, DR5 includes
repeat scans of the southern equatorial stripe, imaging scans across M31 and
the core of the Perseus cluster of galaxies, and the first spectroscopic data
from SEGUE, a survey to explore the kinematics and chemical evolution of the
Galaxy. The catalog database incorporates several new features, including
photometric redshifts of galaxies, tables of matched objects in overlap regions
of the imaging survey, and tools that allow precise computations of survey
geometry for statistical investigations.Comment: ApJ Supp, in press, October 2007. This paper describes DR5. The SDSS
Sixth Data Release (DR6) is now public, available from http://www.sdss.or
Bisphenol A exposure in Mexico City and risk of prematurity: a pilot nested case control study
Abstract Background Presence of Bisphenol A (BPA) has been documented worldwide in a variety of human biological samples. There is growing evidence that low level BPA exposure may impact placental tissue development and thyroid function in humans. The aim of this present pilot study was to determine urinary concentrations of BPA during the last trimester of pregnancy among a small subset of women in Mexico City, Mexico and relate these concentrations to risk of delivering prematurely. Methods A nested case-control subset of 60 participants in the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) study in Mexico City, Mexico were selected based on delivering less than or equal to 37 weeks of gestation and greater than 37 weeks of gestation. Third trimester archived spot urine samples were analyzed by online solid phase extraction coupled with high performance liquid chromatography isotope dilution tandem mass spectrometry. Results BPA was detected in 80.0% (N = 48) of the urine samples; total concentrations ranged from < 0.4 μg/L to 6.7 μg/L; uncorrected geometric mean was 1.52 μg/L. The adjusted odds ratio of delivering less than or equal to 37 weeks in relation to specific gravity adjusted third trimester BPA concentration was 1.91 (95%CI 0.93, 3.91, p-value = 0.08). When cases were further restricted to births occurring prior to the 37th week (n = 12), the odds ratio for specific-gravity adjusted BPA was larger and statistically significant (p < 0.05). Conclusions This is the first study to document measurable levels of BPA in the urine of a population of Mexican women. This study also provides preliminary evidence, based on a single spot urine sample collected during the third trimester, that pregnant women who delivered less than or equal to 37 weeks of gestation and prematurely (< 37 weeks) had higher urinary concentrations of BPA compared to women delivering after 37 weeks.http://deepblue.lib.umich.edu/bitstream/2027.42/78251/1/1476-069X-9-62.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78251/2/1476-069X-9-62.pdfPeer Reviewe
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