801 research outputs found
Diffraction-limited CCD imaging with faint reference stars
By selecting short exposure images taken using a CCD with negligible readout
noise we obtained essentially diffraction-limited 810 nm images of faint
objects using nearby reference stars brighter than I=16 at a 2.56 m telescope.
The FWHM of the isoplanatic patch for the technique is found to be 50
arcseconds, providing ~20% sky coverage around suitable reference stars.Comment: 4 page letter accepted for publication in Astronomy and Astrophysic
Complications of Subcutaneous Contraception: A Review.
Over 62 million women in the United States are of childbearing age and 60% of them use contraception. Subcutaneous contraceptives include implantable contraceptives and subcutaneous injections. Implantable contraception involves subdermal time-release of synthetic progestin, which allows for several years of continuous, highly effective contraception. Its main effects are inhibition of ovulation and thickening of the cervical mucus. Many complications have been associated with subcutaneous contraception, including menstrual disturbances, headache, weight gain, acne, dizziness, mood disturbances, nausea, lower abdominal pain, hair loss, loss of libido, pain at the implant site, neuropathy, and follicular cysts. Using standard search engines, the complications of subcutaneous contraception are reviewed. Patients should be adequately counseled on the possible complications and side effects of subcutaneous contraception to help them make an informed decision when choosing the right contraceptive to meet their needs
The effect of green algal mats on intertidal macrobenthic communities and their predators
Eutrophication by sewage effluent has led to the development of extensive mats of green algae over much of the former open mudlands of Langstone Harbour on the south coast of Britain. The presence of the mal reduces the biomass and diversity of the mud-dwelling infauna but a great increase in the number and biomass of epibenthic animals (primarily Hydrobia ulvae Pennant) produces a total biomass almost twice that of open mudlands. Although the common invertebrates are favoured prey for many estuarine birds these algal areas are avoided by the dense aggregation of waders and wildfowl
ALK Status Testing in Non–Small-Cell Lung Carcinoma by FISH on ThinPrep Slides with Cytology Material
Introduction:Oncogenic anaplastic lymphoma kinase (ALK) gene rearrangements in non–small-cell lung carcinomas (NSCLC) provide the basis for targeted therapy with crizotinib and other specific ALK inhibitors. Treatment eligibility is conventionally determined by the Food and Drug Administration–approved companion diagnostic fluorescence in situ hybridization (FISH) assay on paraffin-embedded tissue (PET). On limited samples such as fine needle aspiration–derived cytoblocks, FISH for ALK is often uninformative. FISH performed on liquid-based ThinPrep slides (ThinPrep-FISH) may represent a robust alternative.Methods:Two hundred thirty cytology samples from 217 patients with advanced NSCLC, including a consecutive series of 179 specimens, were used to generate matched ThinPrep slides and paraffin cytoblocks. The same ThinPrep slides used for cytologic diagnosis were assessed by standard ALK break-apart two-color probe FISH, after etching of tumor areas. Ultrasensitive ALK immunohistochemistry (IHC) on corresponding cytoblocks [D5F3 antibody, OptiView signal amplification] served as the reference data set.Results:ThinPrep-FISH ALK signals were robust in 228 of 230 cases and not compromised by nuclear truncation inherent in paraffin-embedded tissue–FISH; only two samples displayed no signals. Nine of 178 informative cases (5%) in the consecutive series and 18 of 228 informative cases (7.8%) overall were ALK rearranged by ThinPrep-FISH. In 154 informative matched ThinPrep-FISH and cytoblock-IHC samples, 152 were concordant (10, 6.5% ALK status positive; 142, 92.2% ALK status negative), and two (1.3%) were ThinPrep-FISH positive but IHC negative (sensitivity 100%, specificity 98.6%, overall agreement 98.7%).Conclusion:Detection of ALK gene rearrangements in liquid cytology ThinPrep slides derived from patients with NSCLC can be confidently used for clinical ALK molecular testing
Refractive Index of Humid Air in the Infrared: Model Fits
The theory of summation of electromagnetic line transitions is used to
tabulate the Taylor expansion of the refractive index of humid air over the
basic independent parameters (temperature, pressure, humidity, wavelength) in
five separate infrared regions from the H to the Q band at a fixed percentage
of Carbon Dioxide. These are least-squares fits to raw, highly resolved spectra
for a set of temperatures from 10 to 25 C, a set of pressures from 500 to 1023
hPa, and a set of relative humidities from 5 to 60%. These choices reflect the
prospective application to characterize ambient air at mountain altitudes of
astronomical telescopes.Comment: Corrected exponents of c0ref, c1ref and c1p in Table
Neutrino Interactions in Hot and Dense Matter
We study the charged and neutral current weak interaction rates relevant for
the determination of neutrino opacities in dense matter found in supernovae and
neutron stars. We establish an efficient formalism for calculating differential
cross sections and mean free paths for interacting, asymmetric nuclear matter
at arbitrary degeneracy. The formalism is valid for both charged and neutral
current reactions. Strong interaction corrections are incorporated through the
in-medium single particle energies at the relevant density and temperature. The
effects of strong interactions on the weak interaction rates are investigated
using both potential and effective field-theoretical models of matter. We
investigate the relative importance of charged and neutral currents for
different astrophysical situations, and also examine the influence of
strangeness-bearing hyperons. Our findings show that the mean free paths are
significantly altered by the effects of strong interactions and the
multi-component nature of dense matter. The opacities are then discussed in the
context of the evolution of the core of a protoneutron star.Comment: 41 pages, 25 figure
Identification of a Novel Gammaretrovirus in Prostate Tumors of Patients Homozygous for R462Q RNASEL Variant
Ribonuclease L (RNase L) is an important effector of the innate antiviral response. Mutations or variants that impair function of RNase L, particularly R462Q, have been proposed as susceptibility factors for prostate cancer. Given the role of this gene in viral defense, we sought to explore the possibility that a viral infection might contribute to prostate cancer in individuals harboring the R462Q variant. A viral detection DNA microarray composed of oligonucleotides corresponding to the most conserved sequences of all known viruses identified the presence of gammaretroviral sequences in cDNA samples from seven of 11 R462Q-homozygous (QQ) cases, and in one of eight heterozygous (RQ) and homozygous wild-type (RR) cases. An expanded survey of 86 tumors by specific RT-PCR detected the virus in eight of 20 QQ cases (40%), compared with only one sample (1.5%) among 66 RQ and RR cases. The full-length viral genome was cloned and sequenced independently from three positive QQ cases. The virus, named XMRV, is closely related to xenotropic murine leukemia viruses (MuLVs), but its sequence is clearly distinct from all known members of this group. Comparison of gag and pol sequences from different tumor isolates suggested infection with the same virus in all cases, yet sequence variation was consistent with the infections being independently acquired. Analysis of prostate tissues from XMRV-positive cases by in situ hybridization and immunohistochemistry showed that XMRV nucleic acid and protein can be detected in about 1% of stromal cells, predominantly fibroblasts and hematopoietic elements in regions adjacent to the carcinoma. These data provide to our knowledge the first demonstration that xenotropic MuLV-related viruses can produce an authentic human infection, and strongly implicate RNase L activity in the prevention or clearance of infection in vivo. These findings also raise questions about the possible relationship between exogenous infection and cancer development in genetically susceptible individuals
Detection of 21-cm, H2 and Deuterium absorption at z>3 along the line-of-sight to J1337+3152
We report the detection of 21-cm and H2 absorption lines in the same DLA
system (log N(HI)=21.36+-0.10) at zabs=3.17447 towards SDSSJ133724+315254
(z=3.174). We estimate the spin temperature of the gas to be, Ts~600 K,
intermediate between the expected values for cold and warm neutral media. This
suggests that the HI absorption originates from a mixture of different phases.
The total molecular fraction is low, f=10^-7, and H2 rotational level
populations are not in equilibrium. The average abundance of the alpha-elements
is, [S/H]=-1.45. N and Fe are found underabundant with respect to
alpha-elements by ~1.0 dex and ~0.5 dex respectively. Using photoionization
models we conclude that the gas is located more than 270 kpc away from the QSO.
While the position of 21-cm absorption line coincides with the H2 velocity
profile, their centroid are shifted by 2.7+-1.0 km/s from each other. However,
the position of the strongest metal absorption component matches the position
of the 21-cm absorption line within 0.5 km/s. From this, we constrain the
variation of the combination of fundamental constants x=alpha^2 Gp/mu, Delta
x/x=-(1.7+-1.7)x10^-6. This system is unique as we can at the same time have an
independent constrain on mu using H2 lines. However only Werner band absorption
lines are seen and the range of sensitivity coefficients is too narrow to
provide a stringent constraint: Delta mu/mu <= 4.0x10^-4. The VLT/UVES spectrum
reveals another DLA at zabs=3.16768 with log N(HI)=20.41+-0.15 and low
metallicity, [Si/H]=-2.68+-0.11. We derive log N(DI)/N(HI)=-(4.93+-0.15) in
this system. This is a factor of two smaller than the value expected from the
best fitted value of Omega_b from the WMAP 5 yr data. This confirms the
presence of astration of deuterium even at very low metallicity. [abridged]Comment: 14 pages, 11 figures, 4 tables, accepted for publication in MNRA
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