1,067 research outputs found
Star formation in galaxies at z~4-5 from the SMUVS survey: a clear starburst/main-sequence bimodality for Halpha emitters on the SFR-M* plane
We study a large galaxy sample from the Spitzer Matching Survey of the
UltraVISTA ultra-deep Stripes (SMUVS) to search for sources with enhanced 3.6
micron fluxes indicative of strong Halpha emission at z=3.9-4.9. We find that
the percentage of "Halpha excess" sources reaches 37-40% for galaxies with
stellar masses log10(M*/Msun) ~ 9-10, and decreases to <20% at log10(M*/Msun) ~
10.7. At higher stellar masses, however, the trend reverses, although this is
likely due to AGN contamination. We derive star formation rates (SFR) and
specific SFR (sSFR) from the inferred Halpha equivalent widths (EW) of our
"Halpha excess" galaxies. We show, for the first time, that the "Halpha excess"
galaxies clearly have a bimodal distribution on the SFR-M* plane: they lie on
the main sequence of star formation (with log10(sSFR/yr^{-1})<-8.05) or in a
starburst cloud (with log10(sSFR/yr^{-1}) >-7.60). The latter contains ~15% of
all the objects in our sample and accounts for >50% of the cosmic SFR density
at z=3.9-4.9, for which we derive a robust lower limit of 0.066 Msun yr^{-1}
Mpc^{-3}. Finally, we identify an unusual >50sigma overdensity of z=3.9-4.9
galaxies within a 0.20 x 0.20 sq. arcmin region. We conclude that the SMUVS
unique combination of area and depth at mid-IR wavelengths provides an
unprecedented level of statistics and dynamic range which are fundamental to
reveal new aspects of galaxy evolution in the young Universe.Comment: 18 pages, 11 figures, 1 table. Re-submitted to the ApJ, after
addressing referee report. Main changes with respect to v1: a new section and
a new appendix have been added to investigate further the origin and
robustness of the sSFR bimodality. No conclusion change
Wound healing activity of topical application of Aloe vera gel in experimental animal models
Aloe vera gel of 50% and 96.4% were tested for its wound healing activity by topical application in experimental rats. The effect of Aloe vera gel on wound healing was evaluated by wound excision model and histopathology was used to study the effect on wound healing. The effect produced by Aloe vera gel with reference to wound contraction, wound closure, decrease in surface area of wound, tissue regeneration at the wound site and histopathological characteristics were significant in treated rats. The effect of Aloe vera gel on biochemical studies revealed significant increase in collagen and decreased hexosamine content and malondialdehyde levels when compared with control. The present study thus provided scientific rationale for the traditional use of Aloe vera gel for management of wounds
Solving rate equations for electron tunneling via discrete quantum states
We consider the form of the current-voltage curves generated when tunneling
spectroscopy is used to measure the energies of individual electronic energy
levels in nanometer-scale systems. We point out that the voltage positions of
the tunneling resonances can undergo temperature-dependent shifts, leading to
errors in spectroscopic measurements that are proportional to temperature. We
do this by solving the set of rate equations that can be used to describe
electron tunneling via discrete quantum states, for a number of cases important
for comparison to experiments, including (1) when just one spin-degenerate
level is accessible for transport, (2) when 2 spin-degenerate levels are
accessible, with no variation in electron-electron interactions between
eigenstates, and (3) when 2 spin-degenerate levels are accessible, but with
variations in electron-electron interactions. We also comment on the general
case with an arbitrary number of accessible levels. In each case we analyze the
voltage-positions, amplitudes, and widths of the current steps due to the
quantum states.Comment: REVTeX 4, 10 pages, 12 figures, submitted to Phys. Rev. B. Associated
programs available at http://www.ccmr.cornell.edu/~ralph
The Spitzer Matching Survey of the UltraVISTA Ultra-deep Stripes (SMUVS):The Evolution of Dusty and Nondusty Galaxies with Stellar Mass at z = 2–6
The Spitzer Matching Survey of the UltraVISTA Ultra-deep Stripes (SMUVS) has obtained the largest ultradeep Spitzer maps to date in a single field of the sky. We considered the sample of about 66,000 SMUVS sources at z = 2–6 to investigate the evolution of dusty and nondusty galaxies with stellar mass through the analysis of the galaxy stellar mass function (GSMF), extending previous analyses about one decade in stellar mass and up to z = 6. We further divide our nondusty galaxy sample with rest-frame optical colors to isolate red quiescent (“passive”) galaxies. At each redshift, we identify a characteristic stellar mass in the GSMF above which dusty galaxies dominate, or are at least as important as nondusty galaxies. Below that stellar mass, nondusty galaxies compose about 80% of all sources, at all redshifts except at z = 4–5. The percentage of dusty galaxies at z = 4–5 is unusually high: 30%–40% for {M}* ={10}9{--}{10}10.5 {M}ȯ and >80% at M * > 1011 M ⊙, which indicates that dust obscuration is of major importance in this cosmic period. The overall percentage of massive ({log}}10({M}* /{M}ȯ )> 10.6) galaxies that are quiescent increases with decreasing redshift, reaching >30% at z ∼ 2. Instead, the quiescent percentage among intermediate-mass galaxies (with {log}}10({M}* /{M}ȯ )=9.7{--}10.6) stays roughly constant at a ∼10% level. Our results indicate that massive and intermediate-mass galaxies clearly have different evolutionary paths in the young universe and are consistent with the scenario of galaxy downsizing
Labour Market and Social Policy in Italy: Challenges and Changes. Bertelsmann Policy Brief #2016/02
vEight years after the outbreak of the financial crisis, Italy has still to cope with and
overcome a plethora of economic and social challenges. On top of this, it faces an
unfavourable demographic structure and severe disparities between its northern and
southern regions. Some promising reforms have recently been enacted, specifically
targeting poverty and social exclusion. However, much more remains to be done on
the way towards greater economic stability and widely shared prosperity
Quercetin prevents progression of disease in elastase/LPS-exposed mice by negatively regulating MMP expression
Abstract Background Chronic obstructive pulmonary disease (COPD) is characterized by chronic bronchitis, emphysema and irreversible airflow limitation. These changes are thought to be due to oxidative stress and an imbalance of proteases and antiproteases. Quercetin, a plant flavonoid, is a potent antioxidant and anti-inflammatory agent. We hypothesized that quercetin reduces lung inflammation and improves lung function in elastase/lipopolysaccharide (LPS)-exposed mice which show typical features of COPD, including airways inflammation, goblet cell metaplasia, and emphysema. Methods Mice treated with elastase and LPS once a week for 4 weeks were subsequently administered 0.5 mg of quercetin dihydrate or 50% propylene glycol (vehicle) by gavage for 10 days. Lungs were examined for elastance, oxidative stress, inflammation, and matrix metalloproteinase (MMP) activity. Effects of quercetin on MMP transcription and activity were examined in LPS-exposed murine macrophages. Results Quercetin-treated, elastase/LPS-exposed mice showed improved elastic recoil and decreased alveolar chord length compared to vehicle-treated controls. Quercetin-treated mice showed decreased levels of thiobarbituric acid reactive substances, a measure of lipid peroxidation caused by oxidative stress. Quercetin also reduced lung inflammation, goblet cell metaplasia, and mRNA expression of pro-inflammatory cytokines and muc5AC. Quercetin treatment decreased the expression and activity of MMP9 and MMP12 in vivo and in vitro, while increasing expression of the histone deacetylase Sirt-1 and suppressing MMP promoter H4 acetylation. Finally, co-treatment with the Sirt-1 inhibitor sirtinol blocked the effects of quercetin on the lung phenotype. Conclusions Quercetin prevents progression of emphysema in elastase/LPS-treated mice by reducing oxidative stress, lung inflammation and expression of MMP9 and MMP12.http://deepblue.lib.umich.edu/bitstream/2027.42/78260/1/1465-9921-11-131.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78260/2/1465-9921-11-131.pdfPeer Reviewe
Skeletal Muscle Differentiation Evokes Endogenous XIAP to Restrict the Apoptotic Pathway
Myotube apoptosis occurs normally during muscle development and aging but it can lead to destruction of skeletal muscle in neuromuscular diseases. Therefore, understanding how myotube apoptosis is regulated is important for developing novel strategies for treatment of muscle loss. We investigated the regulation of apoptosis in skeletal muscle and report a striking increase in resistance to apoptosis following differentiation. We find mitotic C2C12 cells (myoblast-like cells) are sensitive to cytosolic cytochrome c microinjection. However, differentiated C2C12 cells (myotube-like cells) and primary myotubes are markedly resistant. This resistance is due to endogenous X-linked inhibitor of apoptotic protein (XIAP). Importantly, the selective difference in the ability of XIAP to block myotube but not myoblast apoptosis is not due to a change in XIAP but rather a decrease in Apaf-1 expression. This decrease in Apaf-1 links XIAP to caspase activation and death. Our findings suggest that in order for myotubes to die, they may degrade XIAP, functionally inactivate XIAP or upregulate Apaf-1. Importantly, we identify a role for endogenous Smac in overcoming XIAP to allow myotube death. However, in postmitotic cardiomyocytes, where XIAP also restricts apoptosis, endogenous Smac was not capable of overcoming XIAP to cause death. These results show that as skeletal muscle differentiate, they become resistant to apoptosis because of the ability of XIAP to regulate caspase activation. The increased restriction of apoptosis in myotubes is presumably important to ensure the long term survival of these postmitotic cells as they play a vital role in the physiology of organisms
Spintronic transport and Kondo effect in quantum dots
We investigate the spin-dependent transport properties of quantum-dot based
structures where Kondo correlations dominate the electronic dynamics. The
coupling to ferromagnetic leads with parallel magnetizations is known to give
rise to nontrivial effects in the local density of states of a single quantum
dot. We show that this influence strongly depends on whether charge
fluctuations are present or absent in the dot. This result is confirmed with
numerical renormalization group calculations and perturbation theory in the
on-site interaction. In the Fermi-liquid fixed point, we determine the
correlations of the electric current at zero temperature (shot noise) and
demonstrate that the Fano factor is suppressed below the Poissonian limit for
the symmetric point of the Anderson Hamiltonian even for nonzero lead
magnetizations. We discuss possible avenues of future research in this field:
coupling to the low energy excitations of the ferromagnets (magnons), extension
to double quantum dot systems with interdot antiferromagnetic interaction and
effect of spin-polarized currents on higher symmetry Kondo states such as
SU(4).Comment: 11 pages, 5 figures. Proceedings of the 3rd Intl. Conf. on Physics
and Applications of Spin-Related Phenomena in Semiconductors, Santa Barbara,
200
Feasibility of incorporating genomic knowledge into electronic medical records for pharmacogenomic clinical decision support
In pursuing personalized medicine, pharmacogenomic (PGx) knowledge may help guide prescribing drugs based on a person’s genotype. Here we evaluate the feasibility of incorporating PGx knowledge, combined with clinical data, to support clinical decision-making by: 1) analyzing clinically relevant knowledge contained in PGx knowledge resources; 2) evaluating the feasibility of a rule-based framework to support formal representation of clinically relevant knowledge contained in PGx knowledge resources; and, 3) evaluating the ability of an electronic medical record/electronic health record (EMR/EHR) to provide computable forms of clinical data needed for PGx clinical decision support. Findings suggest that the PharmGKB is a good source for PGx knowledge to supplement information contained in FDA approved drug labels. Furthermore, we found that with supporting knowledge (e.g. IF age <18 THEN patient is a child), sufficient clinical data exists in University of Washington’s EMR systems to support 50% of PGx knowledge contained in drug labels that could be expressed as rules
ALMA Lensing Cluster Survey: an ALMA galaxy signposting a MUSE galaxy group at z=4.3 behind 'El Gordo'
We report the discovery of a Multi Unit Spectroscopic Explorer (MUSE) galaxy
group at z=4.32 lensed by the massive galaxy cluster ACT-CL J0102-4915 (aka El
Gordo) at z=0.87, associated with a 1.2 mm source which is at a 2.07+/-0.88 kpc
projected distance from one of the group galaxies. Three images of the whole
system appear in the image plane. The 1.2 mm source has been detected within
the Atacama Large Millimetre/submillimetre Array (ALMA) Lensing Cluster Survey
(ALCS). As this ALMA source is undetected at wavelengths lambda < 2 microns,
its redshift cannot be independently determined, however, the three lensing
components indicate that it belongs to the same galaxy group at z=4.32. The
four members of the MUSE galaxy group have low to intermediate stellar masses
(~ 10^7-10^{10} Msun) and star formation rates (SFRs) of 0.4-24 Msun/yr,
resulting in high specific SFRs (sSFRs) for two of them, which suggest that
these galaxies are growing fast (with stellar-mass doubling times of only ~
2x10^7 years). This high incidence of starburst galaxies is likely a
consequence of interactions within the galaxy group, which is compact and has
high velocity dispersion. Based on the magnification-corrected sub-/millimetre
continuum flux density and estimated stellar mass, we infer that the ALMA
source is classified as an ordinary ultra-luminous infrared galaxy (with
associated dust-obscured SFR~200-300 Msun/yr) and lies on the star-formation
main sequence. This reported case of an ALMA/MUSE group association suggests
that some presumably isolated ALMA sources are in fact signposts of richer
star-forming environments at high redshifts.Comment: 13 pages including 7 figures and 1 table. Accepted for publication at
the ApJ. Minor changes with respect to version 1. Figure 6 has been expanded
to broaden comparison with the literatur
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