1,552 research outputs found
Immunocytochemical localisation of follicle stimulating hormone (FSH) in normal, benign and malignant human prostates.
Immunocytochemical localisation of follicle stimulating hormone (FSH) was carried out in normal, benign and malignant human prostates by indirect immunoperoxidase technique. Positive staining was observed in the epithelial cells of all the three categories, while the stromal cells showed a weakly positive reaction in a few specimens. The brown reaction product was dispersed in the cytoplasm of the epithelial cells. These observations demonstrate the presence of immunoreactive FSH-like peptide in human prostate. The significance of FSH in the aetiopathology of prostatic disorders is discussed
Comparing PyMorph and SDSS photometry. II. The differences are more than semantics and are not dominated by intracluster light
The Sloan Digital Sky Survey pipeline photometry underestimates the
brightnesses of the most luminous galaxies. This is mainly because (i) the SDSS
overestimates the sky background and (ii) single or two-component Sersic-based
models better fit the surface brightness profile of galaxies, especially at
high luminosities, than does the de Vaucouleurs model used by the SDSS
pipeline. We use the PyMorph photometric reductions to isolate effect (ii) and
show that it is the same in the full sample as in small group environments, and
for satellites in the most massive clusters as well. None of these are expected
to be significantly affected by intracluster light (ICL). We only see an
additional effect for centrals in the most massive halos, but we argue that
even this is not dominated by ICL. Hence, for the vast majority of galaxies,
the differences between PyMorph and SDSS pipeline photometry cannot be ascribed
to the semantics of whether or not one includes the ICL when describing the
stellar mass of massive galaxies. Rather, they likely reflect differences in
star formation or assembly histories. Failure to account for the SDSS
underestimate has significantly biased most previous estimates of the SDSS
luminosity and stellar mass functions, and therefore Halo Model estimates of
the z ~ 0.1 relation between the mass of a halo and that of the galaxy at its
center. We also show that when one studies correlations, at fixed group mass,
with a quantity which was not used to define the groups, then selection effects
appear. We show why such effects arise, and should not be mistaken for physical
effects.Comment: 15 pages, 17 figures, accepted for publication in MNRAS. The PyMorph
luminosities and stellar masses are available at
https://www.physics.upenn.edu/~ameert/SDSS_PhotDec
The high mass end of the stellar mass function: Dependence on stellar population models and agreement between fits to the light profile
We quantify the systematic effects on the stellar mass function which arise
from assumptions about the stellar population, as well as how one fits the
light profiles of the most luminous galaxies at z ~ 0.1. When comparing results
from the literature, we are careful to separate out these effects. Our analysis
shows that while systematics in the estimated comoving number density which
arise from different treatments of the stellar population remain of order < 0.5
dex, systematics in photometry are now about 0.1 dex, despite recent claims in
the literature. Compared to these more recent analyses, previous work based on
Sloan Digital Sky Survey (SDSS) pipeline photometry leads to underestimates of
rho_*(> M_*) by factors of 3-10 in the mass range 10^11 - 10^11.6 M_Sun, but up
to a factor of 100 at higher stellar masses. This impacts studies which match
massive galaxies to dark matter halos. Although systematics which arise from
different treatments of the stellar population remain of order < 0.5 dex, our
finding that systematics in photometry now amount to only about 0.1 dex in the
stellar mass density is a significant improvement with respect to a decade ago.
Our results highlight the importance of using the same stellar population and
photometric models whenever low and high redshift samples are compared.Comment: 18 pages, 17 figures, accepted for publication in MNRAS. The PyMorph
luminosities and stellar masses are available at
https://www.physics.upenn.edu/~ameert/SDSS_PhotDec
Experimental test of the planar tunneling model for ballistic electron emission spectroscopy
Using planar theory of ballistic electron emission spectroscopy with the addition of scattering at the metal-semiconductor interface, we calculate an expected change in the ratio of the collector current (Ic) to the tunnel current (It) as It is varied in the well-known system Au/GaAs(100). This alternative spectroscopy is performed experimentally and is shown to differ drastically from the theory, which nevertheless agrees well with standard voltage spectroscopy. From this discrepancy, we question the applicability of one-dimensional (1D) planar theory to an inherently 3D system
Backup and Recovery Mechanisms of Cassandra Database: A Review
Cassandra is a NoSQL database having a peer-to-peer, ring-type architecture. Cassandra offers fault-tolerance, data replication for higher availability as well as ensures no single point of failure. Given that Cassandra is a NoSQL database, it is evident that it lacks the amount of research that has gone into comparatively older and more widely and broadly used SQL databases. Cassandra’s growing popularity in recent times gives rise to the need of addressing any security-related or recovery-related concerns associated with its usage. This review paper discusses the existing deletion mechanism in Cassandra and presents some identified issues related to backup and recovery in the Cassandra database. Further, failure detection as well as handling of failures such as node failure or data center failure has been explored in the paper. In addition, several possible solutions to address backup and recovery including recovery in case of disasters have been reviewed
Refined procedures for accurate determination of solution structures of nucleic acids by two dimensional nuclear magnetic resonance spectroscopy
New procedures have been described for accurate determination of solution structures of nucleic acids. These are two fold; new two dimensional nuclear magnetic resonance techniques and better approaches for interpretation of nuclear magnetic resonance data for structure determination purposes. The significant development in two dimensional nuclear magnetic resonance techniques for this purpose are ω1 -scaling and recording of pure phase spectra. Use ofω1-scaled correlated and nuclear Overhauser effect spectra for estimation of interproton distances and 1H-1H coupling constants has been described. Computer simulation procedures for exact determination of structure have been described. Experimental spectra demonstrating the application of new procedures have been presented
Robust, data-driven inference in non-linear cosmostatistics
We discuss two projects in non-linear cosmostatistics applicable to very
large surveys of galaxies. The first is a Bayesian reconstruction of galaxy
redshifts and their number density distribution from approximate, photometric
redshift data. The second focuses on cosmic voids and uses them to construct
cosmic spheres that allow reconstructing the expansion history of the Universe
using the Alcock-Paczynski test. In both cases we find that non-linearities
enable the methods or enhance the results: non-linear gravitational evolution
creates voids and our photo-z reconstruction works best in the highest density
(and hence most non-linear) portions of our simulations.Comment: 14 pages, 10 figures. Talk given at "Statistical Challenges in Modern
Astronomy V," held at Penn Stat
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