176 research outputs found
Stellar Populations in the Host Galaxies of Mrk 1014, IRAS 07598+6508, and Mrk 231
We present deep spectroscopic and imaging data of the host galaxies of Mrk
1014, IRAS 07598+6508, and Mrk 231. These objects form part of both the QSO and
the ultraluminous infrared galaxy (ULIG) families, and may represent a
transition stage in an evolutionary scenario. Our imaging shows that all three
objects have highly perturbed hosts with tidal tails and destroyed disks, and
appear to be in the final stages of major mergers. The host galaxies of the
three objects have spectra typical of E+A galaxies, showing simultaneously
features from an old and a young stellar component. We model spectra from
different regions of the host galaxies using Bruzual & Charlot spectral
synthesis models using two component models including an old underlying
population and recent superposed starbursts. Our results indicate a strong
connection between interactions and vigorous bursts of star formation in these
objects. We propose that the starburst ages found are indicative of young ages
for the QSO activity. The young starburst ages found are also consistent with
the intermediate position of these objects in the far infrared color-color
diagram. (abridged)Comment: 28 pages; uses AASTeX 5.02 and includes 6 eps figures. 9 additional
figures in jpeg format. Postscript version including all 15 figures (6264 kb)
available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in
the October issue of A
Resident and family perceptions of the nurse practitioner role in long term care settings: a qualitative descriptive study
BACKGROUND: Research evidence supports the positive impact on resident outcomes of nurse practitioners (NPs) working in long term care (LTC) homes. There are few studies that report the perceptions of residents and family members about the role of the NP in these settings. The purpose of this study was to explore the perceptions of residents and family members regarding the role of the NP in LTC homes. METHODS: The study applied a qualitative descriptive approach. In-depth individual and focus group interviews were conducted with 35 residents and family members from four LTC settings that employed a NP. Conventional content analysis was used to identify themes and sub-themes. RESULTS: Two major themes were identified: NPs were seen as providing resident and family-centred care and as providing enhanced quality of care. NPs established caring relationships with residents and families, providing both informational and emotional support, as well as facilitating their participation in decision making. Residents and families perceived the NP as improving availability and timeliness of care and helping to prevent unnecessary hospitalization. CONCLUSIONS: The perceptions of residents and family members of the NP role in LTC are consistent with the concepts of person-centred and relationship-centred care. The relationships NPs develop with residents and families are a central means through which enhanced quality of care occurs. Given the limited use of NPs in LTC settings, there is an opportunity for health care policy and decision makers to address service inadequacies through strategic deployment of NPs in LTC settings. NPs can use their expert knowledge and skill to assist residents and families to make informed choices regarding their health care and maintain a positive care experience
Fertigation of arugula crops grown in saline soils
Arugula is a leafy vegetable that has been standing out in terms of consumption due to its nutritional content. The crop has low tolerance to water salinity (ECw), and information on the management of fertilization in saline environments is scarce. In this context, this study aimed to analyze the nutritional aspects of arugula under different soil salinity levels and fertilization doses via fertigation. The experiment was conducted in a greenhouse during two production cycles in 2021 in a randomized block design and a 4 x 3 factorial arrangement, with four replications. The treatments consisted of four soil salinity levels (ECse = 0.57, 1.3, 2.3, and 3.3 dS m−1) and three doses of a mineral fertilizer based on the recommended fertilization via fertigation (F1 = 100%, F2 = 50%, and F3 = 25%). The contents of N, P, K, Ca, Mg, S, Na, Cu, Fe, Zn, and Mn were evaluated after harvesting. Salinity directly affected the concentration of mineral elements in arugula leaf during the first cycle, mainly Ca, Mg, Zn, and Mn. The fertigation strategy with 100% of the recommended fertilization showed better results than the other doses for N, P, K, and S. In the second cycle, all elements showed a reduction due to the high ECse, mainly the value of 3.3 dS m−1. The fertigation strategy that used 100% of the recommended fertilization promoted higher nutrient accumulation in arugula. The order of nutrient accumulation in arugula leaf was K>N>Ca>S>Mg>P>Fe>Zn>Mn>Cu.Arugula is a leafy vegetable that has been standing out in terms of consumption due to its nutritional content. The crop has low tolerance to water salinity (ECw), and information on the management of fertilization in saline environments is scarce. In this context, this study aimed to analyze the nutritional aspects of arugula under different soil salinity levels and fertilization doses via fertigation. The experiment was conducted in a greenhouse during two production cycles in 2021 in a randomized block design and a 4 x 3 factorial arrangement, with four replications. The treatments consisted of four soil salinity levels (ECse = 0.57, 1.3, 2.3, and 3.3 dS m−1) and three doses of a mineral fertilizer based on the recommended fertilization via fertigation (F1 = 100%, F2 = 50%, and F3 = 25%). The contents of N, P, K, Ca, Mg, S, Na, Cu, Fe, Zn, and Mn were evaluated after harvesting. Salinity directly affected the concentration of mineral elements in arugula leaf during the first cycle, mainly Ca, Mg, Zn, and Mn. The fertigation strategy with 100% of the recommended fertilization showed better results than the other doses for N, P, K, and S. In the second cycle, all elements showed a reduction due to the high ECse, mainly the value of 3.3 dS m−1. The fertigation strategy that used 100% of the recommended fertilization promoted higher nutrient accumulation in arugula. The order of nutrient accumulation in arugula leaf was K>N>Ca>S>Mg>P>Fe>Zn>Mn>Cu
Heschl's gyrus is more sensitive to tone level than non-primary auditory cortex
Previous neuroimaging studies generally demonstrate a growth in the cortical response with an increase in sound level. However, the details of the shape and topographic location of such growth remain largely unknown. One limiting methodological factor has been the relatively sparse sampling of sound intensities. Additionally, most studies have either analysed the entire auditory cortex without differentiating primary and non-primary regions or have limited their analyses to Heschl's gyrus (HG). Here, we characterise the pattern of responses to a 300-Hz tone presented in 6-dB steps from 42 to 96 dB sound pressure level as a function of its sound level, within three anatomically defined auditory areas; the primary area, on HG, and two non-primary areas, consisting of a small area lateral to the axis of HG (the anterior lateral area, ALA) and the posterior part of auditory cortex (the planum temporale, PT). Extent and magnitude of auditory activation increased non-linearly with sound level. In HG, the extent and magnitude were more sensitive to increasing level than in ALA and PT. Thus, HG appears to have a larger involvement in sound-level processing than does ALA or PT
Discovery of an Excess of Halpha Emitters around 4C 23.56 at z=2.48
We report the discovery of a significant excess of candidate Halpha emitters
(HAEs) in the field of the radio galaxy 4C 23.56 at z=2.483. Using the MOIRCS
near-infrared imager on the Subaru Telescope we found 11 candidate
emission-line galaxies to a flux limit of ~7.5 10^-17 erg s-1 cm-2, which is
about 5 times excess from the expected field counts with ~3-sigma significance.
Three of these are spectroscopically confirmed as redshifted Halpha at z=2.49.
The distribution of candidate emitters on the sky is tightly confined to a
1.2-Mpc-radius area at z=2.49, locating 4C 23.56 at the western edge of the
distribution. Analysis of the deep Spitzer MIPS 24 mu m imaging shows that
there is also an excess of faint MIPS sources. All but two of the 11 HAEs are
also found in the MIPS data. The inferred star-formation rate (SFR) of the HAEs
based on the extinction-corrected Halpha luminosity (median SFR >~100 M_solar
yr-1) is similar to those of HAEs in random fields at z~2. On the other hand,
the MIPS-based SFR for the HAEs is on average 3.6 times larger, suggesting the
existence of the star-formation significanly obscured by dust. The comparison
of the Halpha-based star-formation activities of the HAEs in the 4C 23.56 field
to those in another proto-cluster around PKS 1138-262 at z=2.16 reveals that
the latter tend to have fainter Halpha emission despite similar K-band
magnitudes. This suggests that star-formation may be suppressed in the PKS
1138-262 protocluster relative to the 4C 23.56 protocluster. This difference
among the HAEs in the two proto-clusters at z > 2 may imply that some massive
cluster galaxies are just forming at these epochs with some variation among
clusters.Comment: 29 pages, 13 figures, to be published in PASJ Subaru Special Issue
(2011 Mar.
Ground water and climate change
As the world’s largest distributed store of fresh water, ground water plays a central part in sustaining ecosystems and enabling human adaptation to climate variability and change. The strategic importance of ground water for global water and food security will probably intensify under climate change as more frequent and intense climate extremes (droughts and floods) increase variability in precipitation, soil moisture and surface water. Here we critically review recent research assessing the impacts of climate on ground water through natural and human-induced processes as well as through groundwater-driven feedbacks on the climate system. Furthermore, we examine the possible opportunities and challenges of using and sustaining groundwater resources in climate adaptation strategies, and highlight the lack of groundwater observations, which, at present, limits our understanding of the dynamic relationship between ground water and climate
The Slow-Releasing Hydrogen Sulfide Donor, GYY4137, Exhibits Novel Anti-Cancer Effects In Vitro and In Vivo
The slow-releasing hydrogen sulfide (H2S) donor, GYY4137, caused concentration-dependent killing of seven different human cancer cell lines (HeLa, HCT-116, Hep G2, HL-60, MCF-7, MV4-11 and U2OS) but did not affect survival of normal human lung fibroblasts (IMR90, WI-38) as determined by trypan blue exclusion. Sodium hydrosulfide (NaHS) was less potent and not active in all cell lines. A structural analogue of GYY4137 (ZYJ1122) lacking sulfur and thence not able to release H2S was inactive. Similar results were obtained using a clonogenic assay. Incubation of GYY4137 (400 µM) in culture medium led to the generation of low (<20 µM) concentrations of H2S sustained over 7 days. In contrast, incubation of NaHS (400 µM) in the same way led to much higher (up to 400 µM) concentrations of H2S which persisted for only 1 hour. Mechanistic studies revealed that GYY4137 (400 µM) incubated for 5 days with MCF-7 but not IMR90 cells caused the generation of cleaved PARP and cleaved caspase 9, indicative of a pro-apoptotic effect. GYY4137 (but not ZYJ1122) also caused partial G2/M arrest of these cells. Mice xenograft studies using HL-60 and MV4-11 cells showed that GYY4137 (100–300 mg/kg/day for 14 days) significantly reduced tumor growth. We conclude that GYY4137 exhibits anti-cancer activity by releasing H2S over a period of days. We also propose that a combination of apoptosis and cell cycle arrest contributes to this effect and that H2S donors should be investigated further as potential anti-cancer agents
Detections of Faint Lyman-alpha Emitters at z = 5.7: Galaxy Building Blocks and Engines of Reionization
We report results of a unprecedentedly deep, blind search for Ly-alpha
emitters (LAEs) at z = 5.7 using IMACS, the Inamori-Magellan Areal Camera &
Spectrograph, with the goal of identifying missing sources of reionization that
could also be basic building blocks for today's L* galaxies. We describe how
improvements in wide field imaging with the Baade telescope, upgrades to IMACS,
and the accumulation of ~20 hours of integration per field in excellent seeing
led to the detection of single-emission-line sources as faint as F ~ 2 x
10^{-18} ergs s^{-1} cm^{-2}, a sensitivity 5 times deeper than our first
search (Martin et al. 2008). A reasonable correction for foreground interlopers
implies a steep rise of approximately an order of magnitude in source density
for a factor of four drop in flux, from F = 10^{-17.0} ergs s^{-1} cm^{-2} to F
= 10^{-17.6} (2.5) x 10^{-18} ergs s^{-1} cm^{-2}. At this flux the putative
LAEs have reached a surface density of ~1 per sq arcminute -- a comoving volume
density of 4 x 10^{-3} Mpc^{-3}, several times the density of L* galaxies
today. Such a population of faint LAEs would account for a significant fraction
of the critical flux density required to complete reionization at this epoch,
and would be good candidates for building blocks of stellar mass ~10^{8-9} Msun
for the young galaxies of this epoch.Comment: 15 pages, 12 figures. Accepted 2011 July 20 for publication to Ap
- …