1,245 research outputs found
Monosomic analysis of adult-plant resistance to leaf rust in the Brazilian wheat cultivar 'Toropi'.
Spatially Extended Low Ionization Emission Regions (LIERs) at
We present spatially resolved emission diagnostics for eight
galaxies that demonstrate extended low ionization emission-line regions (LIERs)
over kpc scales. Eight candidates are selected based on their spatial extent
and emission line fluxes from slitless spectroscopic observations with the
HST/WFC3 G141 and G800L grisms in the well-studied GOODS survey fields. Five of
the candidates (62.5%) are matched to X-ray counterparts in the \textit{Chandra
X-Ray Observatory} Deep Fields. We modify the traditional
Baldwin-Philips-Terlevich (BPT) emission line diagnostic diagram to use
[SII]/(H+[NII]) instead of [NII]/H to overcome the blending of
[NII] and H+[NII] in the low resolution slitless grism spectra. We
construct emission line ratio maps and place the individual pixels in the
modified BPT. The extended LINER-like emission present in all of our
candidates, coupled with X-Ray properties consistent with star-forming galaxies
and weak [OIII]5007\AA\ detections, is inconsistent with purely
nuclear sources (LINERs) driven by active galactic nuclei. While recent
ground-based integral field unit spectroscopic surveys have revealed
significant evidence for diffuse LINER-like emission in galaxies within the
local universe , this work provides the first evidence for the
non-AGN origin of LINER-like emission out to high redshifts.Comment: 11 pages, 1 table, 6 figures, accepted for publication in the
Astrophysics Journal (ApJ
Effect of Central Nervous System Metastases on Treatment Discontinuation and Survival in Older Women Receiving Trastuzumab for Metastatic Breast Cancer
Background. Trastuzumab improves survival in HER2-positive women with metastatic breast cancer (MBC). The consequences of longer survival include a higher likelihood of additional metastases, including those in the central nervous system (CNS). The effect of CNS metastases on both trastuzumab discontinuation and survival in older patients has not been described. Patients and Methods. We used the Surveillance Epidemiology and End Results (SEER) Medicare data to identify a cohort of 562 women age 66 or older with MBC who were diagnosed between January 1, 2000 and December 31, 2005, free of CNS metastases, and initiated trastuzumab after MBC diagnosis. Time to discontinuation and time to death were analyzed using proportional hazards models. Results. Newly diagnosed CNS metastases were associated with both higher risk of trastuzumab discontinuation (relative hazard [RH] = 1.78, 95% CI 1.11–2.87) and higher risk of death (RH = 2.49, 95% CI 1.84–3.37). The incidence rate of new CNS metastases was comparable among various sites of metastasis (10.7 to 14.7 per 1,000 patient-months), except for bone which was higher (24.1 per 1,000). Conclusion. The diagnosis of CNS metastases was associated with an increase in both the likelihood of discontinuing trastuzumab therapy as well as the risk of death
Photometric Constraints on the Redshift of z~10 candidate UDFj-39546284 from deeper WFC3/IR+ACS+IRAC observations over the HUDF
Ultra-deep WFC3/IR observations on the HUDF from the HUDF09 program revealed
just one plausible z~10 candidate UDFj-39546284. UDFj-39546284 had all the
properties expected of a galaxy at z~10 showing (1) no detection in the deep
ACS+WFC3 imaging data blueward of the F160W band, exhibiting (2) a blue
spectral slope redward of the break, and showing (3) no prominent detection in
deep IRAC observations. The new, similarly deep WFC3/IR HUDF12 F160W
observations over the HUDF09/XDF allow us to further assess this candidate.
These observations show that this candidate, previously only detected at ~5.9
sigma in a single band, clearly corresponds to a real source. It is detected at
~5.3 sigma in the new H-band data and at ~7.8 sigma in the full 85-orbit H-band
stack. Interestingly, the non-detection of the source (<1 sigma) in the new
F140W observations suggests a higher redshift. Formally, the best-fit redshift
of the source utilizing all the WFC3+ACS (and IRAC+K-band) observations is
11.8+/-0.3. However, we consider the z~12 interpretation somewhat unlikely,
since the source would either need to be ~20x more luminous than expected or
show very high-EW Ly-alpha emission (which seems improbable given the extensive
neutral gas prevalent early in the reionization epoch). Lower-redshift
solutions fail if only continuum models are allowed. Plausible lower-redshift
solutions require that the H-band flux be dominated by line emission such as
Halpha or [OIII] with extreme EWs. The tentative detection of line emission at
1.6 microns in UDFj-39546284 in a companion paper suggests that such emission
may have already been found.Comment: 6 pages, 4 figures, 1 table, accepted for publication in ApJ Letters,
updated to match the version in pres
A potencialidade de Agropyron, espécie afim ao trigo cultivado, como fonte de introgressão de genes agronomicamente importantes.
bitstream/CNPT-2010/40626/1/p-do08.pd
The Most Luminous z~9-10 Galaxy Candidates yet Found: The Luminosity Function, Cosmic Star-Formation Rate, and the First Mass Density Estimate at 500 Myr
[abridged] We present the discovery of four surprisingly bright (H_160 ~ 26 -
27 mag AB) galaxy candidates at z~9-10 in the complete HST CANDELS WFC3/IR
GOODS-N imaging data, doubling the number of z~10 galaxy candidates that are
known, just ~500 Myr after the Big Bang. Two similarly bright sources are also
detected in a systematic re-analysis of the GOODS-S data set. Three of the four
galaxies in GOODS-N are significantly detected at 4.5-6.2sigma in the very deep
Spitzer/IRAC 4.5 micron data, as is one of the GOODS-S candidates. Furthermore,
the brightest of our candidates (at z=10.2+-0.4) is robustly detected also at
3.6 micron (6.9sigma), revealing a flat UV spectral energy distribution with a
slope beta=-2.0+-0.2, consistent with demonstrated trends with luminosity at
high redshift. The abundance of such luminous candidates suggests that the
luminosity function evolves more significantly in phi_* than in L_* at z>~8
with a higher number density of bright sources than previously expected.
Despite the discovery of these luminous candidates, the cosmic star formation
rate density for galaxies with SFR >0.7 M_sun/yr shows an order-of-magnitude
increase in only 170 Myr from z ~ 10 to z ~ 8, consistent with previous
results. Based on the IRAC detections, we derive galaxy stellar masses at z~10,
finding that these luminous objects are typically 10^9 M_sun. The cosmic
stellar mass density at z~10 is log10 rho_* = 4.7^+0.5_-0.8 M_sun Mpc^-3 for
galaxies brighter than M_UV~-18. The remarkable brightness, and hence
luminosity, of these z~9-10 candidates highlights the opportunity for deep
spectroscopy to determine their redshift and nature, demonstrates the value of
additional search fields covering a wider area to understand star-formation in
the very early universe, and highlights the opportunities for JWST to map the
buildup of galaxies at redshifts much earlier than z~10.Comment: 20 pages, 12 figures, changed to match resubmitted version to Ap
Genetic stability in synthetic wheat accessions: cytogenetic evaluation as a support in breeding programs.
ABSTRACT: Synthetic wheat is developed by crossing tetraploid species ( Triticum turgidum , AABB) with a diploid species ( Aegilops tauschii , DD), followed by chromosome duplication through the use of colchicine to restore the resultant sterile hybrid to a fertile hexaploid plant. The main importance of producing synthetically improved wheat is to increase their genetic variability and to incorporate genes that code for resistance to biotic and abiotic stressors. This study aimed to evaluate the presence of micronuclei (MN) and the meiotic index (MI) in the tetrad phase in synthetic wheat accessions and cultivars ( Triticum aestivum ) stored at the Germplasm Bank of Embrapa Trigo (Brazil), in order to identify and select genetically stable accessions for plant improvement. Five plants were collected by genotype, prior to anthesis, and the tissues were fixed in Carnoy solution. Cytological slides were prepared by the smash method, and the cells were dyed with 1% acetocarmine and observed under an optical microscope. Presence of MN was observed in all genotypes analyzed, and variability of genetic stability was reported in the two years of analysis. In 2014, the highest MI of synthetic wheat accessions was 96.86% and the lowest was 46.32%. In 2015, the highest MI was 96.60% and the lowest was 47.96%. Based on the results, some genotypes were considered meiotically stable and suitable for use in wheat breeding programs
Corporate social performance and the psychological contract
This study investigates the role of corporate social performance (CSP) within the psychological contract to better illuminate the micro-processes through which CSP promotes improved firm–stakeholder relationships. It extends the study of psychological contract breach beyond the dyadic relationship between the organization and the employee through an analysis of the impact of employee perceptions of internal and external CSP on psychological contract breach. In so doing, we add significantly to the growing evidence base in relation to if, how, and when affective commitment is enhanced by CSP by explicitly accounting for the role of employee expectations in respect of their employers’ socially responsible initiatives in shaping employees’ attitudinal outcomes.25 page(s
Increasing alkyl chain length in a series of layered metal–organic frameworks aids ultrasonic exfoliation to form nanosheets
Metal–organic framework nanosheets (MONs) are attracting increasing attention as a diverse class of two-dimensional materials derived from metal–organic frameworks (MOFs). The principles behind the design of layered MOFs that can readily be exfoliated to form nanosheets, however, remain poorly understood. Here we systematically investigate an isoreticular series of layered MOFs functionalized with alkoxy substituents in order to understand the effect of substituent alkyl chain length on the structure and properties of the resulting nanosheets. A series of 2,5-alkoxybenzene-1,4-dicarboxylate ligands (O2CC6H2(OR)2CO2, R = methyl–pentyl, 1–5, respectively) was used to synthesize copper paddle-wheel MOFs. Rietveld and Pawley fitting of powder diffraction patterns for compounds Cu(3–5)(DMF) showed they adopt an isoreticular series with two-dimensional connectivity in which the interlayer distance increases from 8.68 Å (R = propyl) to 10.03 Å (R = pentyl). Adsorption of CO2 by the MOFs was found to increase from 27.2 to 40.2 cm3 g–1 with increasing chain length, which we attribute to the increasing accessible volume associated with increasing unit-cell volume. Ultrasound was used to exfoliate the layered MOFs to form MONs, with shorter alkyl chains resulting in higher concentrations of exfoliated material in suspension. The average height of MONs was investigated by AFM and found to decrease from 35 ± 26 to 20 ± 12 nm with increasing chain length, with the thinnest MONs observed being only 5 nm, corresponding to five framework layers. These results indicate that careful choice of ligand functionalities can be used to tune nanosheet structure and properties, enabling optimization for a variety of applications
First look with JWST spectroscopy: galaxies resemble local analogues
Deep images and near-IR spectra of galaxies in the field of the lensing
cluster SMACS J0723.3-7327 were recently taken in the Early Release
Observations program of JWST. Among these, two NIRSpec spectra of galaxies at
and one at were obtained, revealing for the first time
rest-frame optical emission line spectra of galaxies in the epoch of
reionization, including the detection of the important[OIII]4363 auroral line
(see JWST PR 2022-035). We present an analysis of the emission line properties
of these galaxies, finding that these galaxies have a high excitation (as
indicated by high ratios of [OIII]/[OII], [NeIII]/[OII]), strong
[OIII]4363/H, high equivalent widths, and other properties which are
typical of low-metallicity star-forming galaxies. Using the direct method we
determine oxygen abundances of in two galaxies, and
a lower metallicity of in the galaxy
using different strong line methods. More accurate metallicity determinations
will require better data. With stellar masses estimated from SED fits, we find
that the three galaxies lie close to or below the mass-metallicity
relation. Overall, these first galaxy spectra at show a strong
resemblance of the emission lines properties of galaxies in the epoch of
reionization with those of relatively rare local analogues previously studied
from the SDSS. Clearly, the first JWST observations demonstrate already the
incredible power of spectroscopy to reveal properties of galaxies in the early
Universe.Comment: 6 pages, 6 Figures. Accepted for publication in Astronomy &
Astrophysics Letter
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