427 research outputs found
Modeling, synthesis, and characterization of thin film copper oxide for solar cells
The modeling, growth, and characterization of
Copper Oxide thin films for solar cell applications are
reported. Cu_2O has several attractive properties which
include its direct band gap (Eg=2.17 eV) for use in photoelectrolysis
of water and use in tandem multi-junction
cells. Detailed balance calculations predict efficiencies on
the order of 20% while Cu_2O cells have yet to even pass
2% efficiency. The device physics model reveals that
defects, particularly at the heterojunction interface, are the
main reason for lowered efficiencies. Epitaxial Cu_2O (100)
thin films on MgO are fabricated using RF Oxygen plasma
MBE. The films are quite smooth and showed mobilites in
the range of 10-100 cm^2/V*sec and carrier concentrations
in the range of 10^(14)-10^(17). Finally, the epitaxial growth of
Cu_2O on a MgO template is demonstrated
Core promoter short tandem repeats as evolutionary switch codes for primate speciation
Alteration in gene expression levels underlies many of the phenotypic differences across species. Because of their highly mutable nature, proximity to the +1 transcription start site (TSS), and the emerging evidence of functional impact on gene expression, core promoter short tandem repeats (STRs) may be considered an ideal source of variation across species. In a genome-scale analysis of the entire Homo sapiens protein-coding genes, we have previously identified core promoters with at least one STR of ≥6-repeats, with possible selective advantage in this species. In the current study, we performed reverse analysis of the entire Homo sapiens orthologous genes in mouse in the Ensembl database, in order to identify conserved STRs that have shrunk as an evolutionary advantage to humans. Two protocols were used to minimize ascertainment bias. Firstly, two species sharing a more recent ancestor with Homo sapiens (i.e. Pan troglodytes and Gorilla gorilla gorilla) were also included in the study. Secondly, four non-primate species encompassing the major orders across Mammals, including Scandentia, Laurasiatheria, Afrotheria, and Xenarthra were analyzed as out-groups. We introduce STR evolutionary events specifically identical in primates (i.e. Homo sapiens, Pan troglodytes, and Gorilla gorilla gorilla) vs. non-primate out-groups. The average frequency of the identically shared STR motifs across those primates ranged between 0.00005 and 0.06. The identified genes are involved in important evolutionary and developmental processes, such as normal craniofacial development (TFAP2B), regulation of cell shape (PALMD), learning and long-term memory (RGS14), nervous system development (GFRA2), embryonic limb morphogenesis (PBX2), and forebrain development (APAF1). We provide evidence of core promoter STRs as evolutionary switch codes for primate speciation, and the first instance of identity-by-descent for those motifs at the interspecies level. © 2014 Wiley Periodicals, Inc
Some results on singular value inequalities of compact operators in Hilbert space
We prove several singular value inequalities for sum and product of compact
operators in Hilbert space. Some of our results generalize the previous
inequalities for operators. Also, applications of some inequalities are given.Comment: 1
Some inequalities associated with the Hermite-Hadamard inequalities for operator h-convex functions
We introduce the concept of operator h-convex functions for positive linear maps, and prove some Hermite-Hadamard type inequalities for these functions. As applications, we obtain several trace inequalities for operators
The incidence of prostate cancer in Iran: Results of a population-based cancer registry
Background: Little is known about the epidemiology of prostate cancer in Iranian men. We carried out an active prostate cancer surveillance program in five provinces of Iran. Methods: Data used in this study were obtained from population-based cancer registries between 1996 and 2000. Results: The age-standardized incidence rate of prostate carcinoma in the five provinces was 5.1 per 100,000 person-years. No significant difference was seen in the age-standardized incidence rate of prostate cancer within the provinces studied. The mean±SD age of patients with prostate cancer was 67±13.5 years. Conclusion: The incidence of prostate cancer in Iran is very low as compared to the Western countries. This can partly be explained by lack of nationwide screening program, younger age structure and quality of cancer registration system in Iran
Evaluation of metallothionein protein as a biomarker of Mercury pollution in Scat (Scatophagus argus)
Total Metallothionein (MT) biosynthesis and Mercury bioaccumulation under control & acute Mercury exposure were investigated in Scat (Scatophagus argus). Tissues from liver and gill of samples Scats were exposed to different Mercury concentrations (10, 20, 30μ g/l) for 24, 48, 72 hours. Mercury contents were determined through Cold Vapour Atomic Absorption Spectrometry (CVAAS). Total MT levels were determined by Enzyme-linked Immunosorbent Assay (ELISA) method. Induction of MT during exposure was tissue specific, displaying different response patterns in gill and liver. Mercury accumulated in liver much stronger than gill and the latter also showed lower MT level. Although after exposure to different mercury concentration during different periods, MT biosynthesis in liver showed a significant increase (P<0.05) but in gill did not significantly modify total MT except for 72h exposure at 30 g/l. Nonetheless, the relationship between MT biosynthesis and Mercury bioaccumulation in both tissues was significant. The results suggest that this form of MT presence in S. argus was Hg-inducible and could be extended as a biomarker of Mercury pollution in marine ecosystems and especially in Persian Gulf
The Molecular Gas Reservoirs of Galaxies: A comparison of CO(1-0) and dust-based molecular gas masses
We test the use of long-wavelength dust continuum emission as a molecular gas
tracer at high redshift, via a unique sample of 12, z~2 galaxies with
observations of both the dust continuum and CO(1-0) line emission (obtained
with the Atacama Large Millimeter Array and Karl G. Jansky Very Large Array,
respectively). Our work is motivated by recent, high redshift studies that
measure molecular gas masses (\ensuremath{\rm{M}_{\rm{mol}}}) via a calibration
of the rest-frame m luminosity () against the
CO(1-0)-derived \ensuremath{\rm{M}_{\rm{mol}}}\ of star-forming galaxies. We
hereby test whether this method is valid for the types of high-redshift,
star-forming galaxies to which it has been applied. We recover a clear
correlation between the rest-frame m luminosity, inferred from the
single-band, long-wavelength flux, and the CO(1-0) line luminosity, consistent
with the samples used to perform the m calibration. The molecular gas
masses, derived from , agree to within a factor of
two with those derived from CO(1-0). We show that this factor of two
uncertainty can arise from the values of the dust emissivity index and
temperature that need to be assumed in order to extrapolate from the observed
frequency to the rest-frame at 850. The extrapolation to
850 therefore has a smaller effect on the accuracy of \Mmol\
derived via single-band dust-continuum observations than the assumed
CO(1-0)-to-\ensuremath{\rm{M}_{\rm{mol}}}\ conversion factor. We therefore
conclude that single-band observations of long-wavelength dust emission can be
used to reliably constrain the molecular gas masses of massive, star-forming
galaxies at
Eurasian house mouse (Mus musculus L.) differentiation at microsatellite loci identifies the Iranian plateau as a phylogeographic hotspot
Background: The phylogeography of the house mouse (Mus musculus L.), an emblematic species for genetic and biomedical studies, is only partly understood, essentially because of a sampling bias towards its most peripheral populations in Europe, Asia and the Americas. Moreover, the present-day phylogeographic hypotheses stem mostly from the study of mitochondrial lineages. In this article, we complement the mtDNA studies with a comprehensive survey of nuclear markers (19 microsatellite loci) typed in 963 individuals from 47 population samples, with an emphasis on the putative Middle-Eastern centre of dispersal of the species.
Results: Based on correspondence analysis, distance and allele-sharing trees, we find a good coherence between geographical origin and genetic make-up of the populations. We thus confirm the clear distinction of the three best described peripheral subspecies, M. m. musculus, M. m. domesticus and M. m. castaneus. A large diversity was found in the Iranian populations, which have had an unclear taxonomic status to date. In addition to samples with clear affiliation to M. m. musculus and M. m. domesticus, we find two genetic groups in Central and South East Iran, which are as distinct from each other as they are from the south-east Asian M. m. castaneus. These groups were previously also found to harbor distinct mitochondrial haplotypes.
Conclusion: We propose that the Iranian plateau is home to two more taxonomic units displaying complex
primary and secondary relationships with their long recognized neighbours. This central region emerges as the area with the highest known diversity of mouse lineages within a restricted geographical area, designating it as the focal place to study the mechanisms of speciation and diversification of this species
The Bright and Dark Sides of High-Redshift starburst galaxies from {\it Herschel} and {\it Subaru} observations
We present rest-frame optical spectra from the FMOS-COSMOS survey of twelve
\textit{Herschel} starburst galaxies, with Star Formation Rate
(SFR) elevated by 8, on average, above the star-forming Main Sequence
(MS). Comparing the H to IR luminosity ratio and the Balmer Decrement
we find that the optically-thin regions of the sources contain on average only
percent of the total SFR whereas percent comes from an
extremely obscured component which is revealed only by far-IR observations and
is optically-thick even in H. We measure the [NII]/H
ratio, suggesting that the less obscured regions have a metal content similar
to that of the MS population at the same stellar masses and redshifts. However,
our objects appear to be metal-rich outliers from the metallicity-SFR
anticorrelation observed at fixed stellar mass for the MS population. The
[SII]/[SII] ratio from the average spectrum indicates an
electron density , larger than what
estimated for MS galaxies but only at the 1.5 level. Our results
provide supporting evidence that high- MS outliers are the analogous of
local ULIRGs, and are consistent with a major merger origin for the starburst
event.Comment: 6 pages, 4 figures, Accepted for publication in ApJ Letter
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