Dietary mineral supplies in Africa Joy, Edward J. M; Ander, E. Louise; Young, Scott D ...
Physiologia plantarum,
July 2014, Letnik:
151, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Dietary micronutrient deficiencies (MNDs) are widespread, yet their prevalence can be difficult to assess. Here, we estimate MND risks due to inadequate intakes for seven minerals in Africa using ...food supply and composition data, and consider the potential of food‐based and agricultural interventions. Food Balance Sheets (FBSs) for 46 countries were integrated with food composition data to estimate per capita supply of calcium (Ca), copper (Cu), iron (Fe), iodine (I), magnesium (Mg), selenium (Se) and zinc (Zn), and also phytate. Deficiency risks were quantified using an estimated average requirement (EAR) ‘cut‐point’ approach. Deficiency risks are highest for Ca (54% of the population), followed by Zn (40%), Se (28%) and I (19%, after accounting for iodized salt consumption). The risk of Cu (1%) and Mg (<1%) deficiency are low. Deficiency risks are generally lower in the north and west of Africa. Multiple MND risks are high in many countries. The population‐weighted mean phytate supply is 2770 mg capita⁻¹ day⁻¹. Deficiency risks for Fe are lower than expected (5%). However, ‘cut‐point’ approaches for Fe are sensitive to assumptions regarding requirements; e.g. estimates of Fe deficiency risks are 43% under very low bioavailability scenarios consistent with high‐phytate, low‐animal protein diets. Fertilization and breeding strategies could greatly reduce certain MNDs. For example, meeting HarvestPlus breeding targets for Zn would reduce dietary Zn deficiency risk by 90% based on supply data. Dietary diversification or direct fortification is likely to be needed to address Ca deficiency risks.
We present new measurements of the quasar luminosity function (LF) at z ∼ 6 over an unprecedentedly wide range of the rest-frame ultraviolet luminosity M1450 from −30 to −22 mag. This is the fifth in ...a series of publications from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which exploits the deep multiband imaging data produced by the Hyper Suprime-Cam Subaru Strategic Program survey. The LF was calculated with a complete sample of 110 quasars at 5.7 ≤ z ≤ 6.5, which includes 48 SHELLQs quasars discovered over 650 deg2 and 63 brighter quasars discovered by the Sloan Digital Sky Survey and the Canada-France-Hawaii Quasar Survey (including one overlapping object). This is the largest sample of z ∼ 6 quasars with a well-defined selection function constructed to date, which has allowed us to detect significant flattening of the LF at its faint end. A double power-law function fit to the sample yields a faint-end slope , a bright-end slope , a break magnitude , and a characteristic space density Gpc−3 mag−1. Integrating this best-fit model over the range −18 < M1450 < −30 mag, quasars emit ionizing photons at the rate of s−1 Mpc−3 at z = 6.0. This is less than 10% of the critical rate necessary to keep the intergalactic medium ionized, which indicates that quasars are not a major contributor to cosmic reionization.
We report the discovery of 28 quasars and 7 luminous galaxies at 5.7 ≤ z ≤ 7.0. This is the tenth in a series of papers from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, ...which exploits the deep multiband imaging data produced by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. The total number of spectroscopically identified objects in SHELLQs has now grown to 93 high-z quasars, 31 high-z luminous galaxies, 16 O iii emitters at z ∼ 0.8, and 65 Galactic cool dwarfs (low-mass stars and brown dwarfs). These objects were found over 900 deg2, surveyed by HSC between 2014 March and 2018 January. The full quasar sample includes 18 objects with very strong and narrow Ly emission, whose stacked spectrum is clearly different from that of other quasars or galaxies. While the stacked spectrum shows N v λ1240 emission and resembles that of lower-z narrow-line quasars, the small Ly width may suggest a significant contribution from the host galaxies. Thus, these objects may be composites of quasars and star-forming galaxies.
Abstract
We present the spectroscopic discovery of 69 quasars at 5.8 <
z
< 7.0, drawn from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) imaging survey data. This is the 16th publication ...from the Subaru High-
z
Exploration of Low-Luminosity Quasars (SHELLQs) project, and it completes identification of all but the faintest candidates (i.e.,
i
-band dropouts with
z
AB
< 24 and
y
-band detections, and
z
-band dropouts with
y
AB
< 24) with Bayesian quasar probability
P
Q
B
>
0.1
in the HSC-SSP third public data release (PDR3). The sample reported here also includes three quasars with
P
Q
B
<
0.1
at
z
∼ 6.6, which we selected in an effort to completely cover the reddest point sources with simple color cuts. The number of high-
z
quasars discovered in SHELLQs has now grown to 162, including 23 type II quasar candidates. This paper also presents identification of seven galaxies at 5.6 <
z
< 6.7, an O
iii
emitter at
z
= 0.954, and 31 Galactic cool stars and brown dwarfs. High-
z
quasars and galaxies compose 75% and 16%, respectively, of all the spectroscopic SHELLQs objects that pass our latest selection algorithm with the PDR3 photometry. That is, a total of 91% of the objects lie at
z
> 5.6. This demonstrates that the algorithm has very high efficiency, even though we are probing an unprecedentedly low luminosity population down to
M
1450
∼ −21 mag.
Quasar Luminosity Function at z = 7 Matsuoka, Yoshiki; Onoue, Masafusa; Iwasawa, Kazushi ...
Astrophysical journal. Letters,
06/2023, Letnik:
949, Številka:
2
Journal Article
Recenzirano
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Abstract
We present the quasar luminosity function (LF) at
z
= 7, measured with 35 spectroscopically confirmed quasars at 6.55 <
z
< 7.15. The sample of 22 quasars from the Subaru High-
z
Exploration ...of Low-Luminosity Quasars (SHELLQs) project, combined with 13 brighter quasars in the literature, covers an unprecedentedly wide range of rest-frame ultraviolet magnitudes over −28 <
M
1450
< −23. We found that the binned LF flattens significantly toward the faint end populated by the SHELLQs quasars. A maximum likelihood fit to a double power-law model has a break magnitude
M
1450
*
=
−
25.60
−
0.30
+
0.40
, a characteristic density
Φ
*
=
1.35
−
0.30
+
0.47
Gpc
−3
mag
−1
, and a bright-end slope
β
=
−
3.34
−
0.57
+
0.49
, when the faint-end slope is fixed to
α
= −1.2 as observed at
z
≤ 6. The overall LF shape remains remarkably similar from
z
= 4 to 7, while the amplitude decreases substantially toward higher redshifts, with a clear indication of an accelerating decline at
z
≥ 6. The estimated ionizing photon density, 10
48.2±0.1
s
−1
Mpc
−3
, is less than 1% of the critical rate to keep the intergalactic medium ionized at
z
= 7, and thus indicates that quasars are not a major contributor to cosmic reionization.
We report the discovery of 41 new high-z quasars and luminous galaxies that were spectroscopically identified at 5.7 ≤ z ≤ 6.9. This is the fourth in a series of papers from the Subaru High-z ...Exploration of Low-Luminosity Quasars (SHELLQs) project, based on the deep multi-band imaging data collected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. We selected the photometric candidates using a Bayesian probabilistic algorithm and then carried out follow-up spectroscopy with the Gran Telescopio Canarias and the Subaru Telescope. Combined with the sample presented in the previous papers, we have now spectroscopically identified 137 extremely red HSC sources over about 650 deg2, which includes 64 high-z quasars, 24 high-z luminous galaxies, 6 O iii emitters at z ∼ 0.8, and 43 Galactic cool dwarfs (low-mass stars and brown dwarfs). The new quasars span in luminosity range from M1450 ∼ −26 to −22 mag, and continue to populate luminosities a few magnitudes lower than have been probed by previous wide-field surveys. In a companion paper, we derive the quasar luminosity function at z ∼ 6 over an unprecedentedly wide range of M1450 ∼ −28 to −21 mag, exploiting the SHELLQs and other survey outcomes.
Abstract
We present spectroscopic identification of 32 new quasars and luminous galaxies discovered at 5.7 < z ≤ 6.8. This is the second in a series of papers presenting the results of the Subaru ...High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which exploits the deep multi-band imaging data produced by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. The photometric candidates were selected by a Bayesian probabilistic algorithm, and then observed with spectrographs on the Gran Telescopio Canarias and the Subaru Telescope. Combined with the sample presented in the previous paper of this series, we have now identified 64 HSC sources over about 430 deg2, which include 33 high-z quasars, 14 high-z luminous galaxies, two O iii emitters at z ∼ 0.8, and 15 Galactic brown dwarfs. The new quasars have considerably lower luminosity (M1450 ∼ −25 to −22 mag) than most of the previously known high-z quasars. Several of these quasars have luminous (>1043 erg s−1) and narrow (< 500 km s−1) Lyα lines, and also a possible mini broad-absorption-line system of N v λ1240 in the composite spectrum, which clearly separate them from typical quasars. On the other hand, the high-z galaxies have extremely high luminosities (M1450 ∼ −24 to −22 mag) compared to other galaxies found at similar redshifts. With the discovery of these new classes of objects, we are opening up new parameter spaces in the high-z Universe. Further survey observations and follow-up studies of the identified objects, including the construction of the quasar luminosity function at z ∼ 6, are ongoing.
Mental disorders are responsible for a high level of disability burden in students attending university. However, many universities have limited resources available to support student mental health. ...Technology-based interventions may be highly relevant to university populations. Previous reviews have targeted substance use and eating disorders in tertiary students. However, the effectiveness of technology-based interventions for other mental disorders and related issues has not been reviewed.
To systematically review published randomized trials of technology-based interventions evaluated in a university setting for disorders other than substance use and eating disorders.
The PubMed, PsycInfo, and Cochrane Central Register of Controlled Trials databases were searched using keywords, phrases, and MeSH terms. Retrieved abstracts (n=1618) were double screened and coded. Included studies met the following criteria: (1) the study was a randomized trial or a randomized controlled trial, (2) the sample was composed of students attending a tertiary institution, (3) the intervention was delivered by or accessed using a technological device or process, (4) the age range of the sample was between 18 and 25 years, and (5) the intervention was designed to improve, reduce, or change symptoms relating to a mental disorder.
A total of 27 studies met inclusion criteria for the present review. Most of the studies (24/27, 89%) employed interventions targeting anxiety symptoms or disorders or stress, although almost one-third (7/24, 29%) targeted both depression and anxiety. There were a total of 51 technology-based interventions employed across the 27 studies. Overall, approximately half (24/51, 47%) were associated with at least 1 significant positive outcome compared with the control at postintervention. However, 29% (15/51) failed to find a significant effect. Effect sizes were calculated for the 18 of 51 interventions that provided sufficient data. Median effect size was 0.54 (range -0.07 to 3.04) for 8 interventions targeting depression and anxiety symptoms and 0.84 (range -0.07 to 2.66) for 10 interventions targeting anxiety symptoms and disorders. Internet-based technology (typically involving cognitive behavioral therapy) was the most commonly employed medium, being employed in 16 of 27 studies and approximately half of the 51 technology-based interventions (25/51, 49%). Distal and universal preventive interventions were the most common type of intervention. Some methodological problems were evident in the studies, with randomization methods either inadequate or inadequately described, few studies specifying a primary outcome, and most of the studies failing to undertake or report appropriate intent-to-treat analyses.
The findings of this review indicate that although technological interventions targeting certain mental health and related problems offer promise for students in university settings, more high quality trials that fully report randomization methods, outcome data, and data analysis methods are needed.
Selenium (Se) is an essential trace element for humans and livestock. In the UK, human Se intake and status has declined since the 1980s. This is primarily due to the increased use of wheat (Triticum ...aestivum L.) grown in UK soils which are naturally low in Se. The aim of this study was to determine the potential for increasing grain Se concentration in a high-yielding UK wheat crop using fertilisers. The crop response of winter-wheat to Se fertilisation was determined under standard field conditions in two consecutive years at up to 10 sites. Selenium fertilisers were applied as high-volume drenches of sodium selenate solution, or as granular Se-containing products. Yield and harvest index were unaffected by Se fertilisation. Under all treatments, grain Se concentration increased by 16-26 ng Se g⁻¹ fresh weight (FW) per gram Se ha⁻¹ applied. An application of 10 g Se ha⁻¹ would thereby increase the Se concentration of most UK wheat grain 10-fold from current ambient levels and agronomic biofortification of UK-grown wheat is feasible. Total recovery (grain and straw) of applied Se was 20-35%. The fate of Se in the food-chain and in the soil must be determined in order to optimize the efficiency of this process.
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