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"Ellis, Richard"
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Tuna : love, death, and mercury
Examines the natural history of the tuna, one of the world's most endangered marine animals, revealing how the increasing demand for sushi has caused a devastating overfishing of the tuna and detailing the implications of its potential extinction.
Book
JWST/NIRSpec Observations of Lyman α Emission in Star-forming Galaxies at 6.5 ≲ z ≲ 13
We present an analysis of JWST Lyα spectroscopy of z ≳ 6.5 galaxies, using observations in the public archive covering galaxies in four independent fields: Great Observatories Origins Deep Survey (GOODS)-N, GOODS-S, A2744, and the Extended Groth Strip (EGS). We measure the Lyα emission line properties for a sample of 210 z ≃ 6.5–13 galaxies, with redshifts confirmed independently of Lyα in all cases. We present three new detections of Lyα emission in JWST spectra, including a large equivalent width (EW; =143 Å) Lyα emitter (LAE) with strong C iv emission (EW = 21 Å) at z = 7.1 in GOODS-N. We measure the redshift-dependent Lyα EW distribution across our sample. We find that strong Lyα emission (EW > 25 Å) becomes increasingly rare at earlier epochs, suggesting that the transmission of Lyα photons decreases by 4× between z ≃ 5 and z ≃ 9. We describe potential implications for the intergalactic medium neutral fraction. There is significant field-to-field variance in the LAE fraction. In contrast to the three other fields, the EGS shows no evidence for reduced transmission of Lyα photons at z ≃ 7–8, suggesting a significantly ionized sight line may be present in the field. We use available NIRCam grism observations from the First Reionization Epoch Spectroscopically Complete Observations survey to characterize overdensities on large scales around known LAEs in the GOODS fields. The strongest overdensities appear linked with extremely strong Lyα detections (EW > 50 Å) in most cases. Future Lyα spectroscopy with JWST has the potential to constrain the size of ionized regions around early galaxy overdensities, providing a new probe of the reionization process.
Journal Article
Temporal patterns of seed quality development, decline, and timing of maximum quality during seed development and maturation
The long-standing hypothesis that seed quality improves during seed filling, is greatest at the end of seed filling, and declines thereafter (because seed deterioration was assumed to begin then), provided a template for research in seed quality development. It was rejected by investigations where seed quality was shown to improve throughout both seed development and maturation until harvest maturity, before seed deterioration was first observed. Several other temporal patterns of seed quality development and decline have also been reported. These are portrayed and compared. The assessment suggests that the original hypothesis was too simple, because it combined several component hypotheses: (a) the seed improvement (only) phase ends before seed deterioration (only) commences; (b) there is only a brief single point in time during seed development and maturation when, in all circumstances, seed quality is maximal; (c) the seed quality improvement phase coincides perfectly with seed filling, with deterioration only post-seed filling. It is concluded that the search for the single point of maximum seed quality was a false quest because (a) seed improvement and deterioration may cycle (sequentially if not simultaneously) during seed development and maturation; (b) the relative sensitivity of the rates of improvement and deterioration to environment may differ; (c) the period of maximum quality may be brief or extended. Hence, when maximum quality is first attained, and for how long it is maintained, during seed development and maturation varies with genotype and environment. This is pertinent to quality seed production in current and future climates as it will be affected by climate change and a likelihood of more frequent coincidence of brief periods of extreme temperatures with highly sensitive phases of seed development and maturation. This is a possible tipping point for food security and for ecological diversity.
Journal Article
Assessment of the causes and extent of damage to trees of Olea europaea subsp. cuspidata (Wall. and G.Don) Cif. (wild olive) in the mountains of Oman
Olea europaea subsp. cuspidata (Wall. and G.Don) Cif. (wild olive) is one of the key woody species in the mountain habitats of Oman. Wild olive trees are scattered, isolated, and at risk from several threats including climate change, urbanization, browsing, human activity, and the introduction of non-native species. One hundred and eighty-four trees from eight locations in three mountain ranges (Eastern Hajar, Western Hajar, and Dhofar) in Oman were assessed. The extent of damage to trees caused by browsing, drought (dead branches), and human activity (cutting and burning) was scored between 10 June and 5 July 2020. Most olive trees in these mountain ranges exhibited moderate damage, ranging from 21% to 45%, while 29% of wild olive trees experienced high levels of damage, ranging from 45% to 64%. Wild olive trees in the Western Hajar Mountains and Dhofar Mountains showed the greatest damage. Tree height differed significantly among these eight locations across Oman. There was a negative correlation between tree damage and tree height and a positive correlation between tree damage and site slope but no correlation between tree damage and site altitude. No natural regeneration of wild olive was detected in any of the eight locations. Urbanization and over-browsing are putting wild olive at high risk. Action to protect these mountain habitats will be essential to conserve this ecologically important subspecies in these mountains.
Journal Article
Old Tip vs. the Sly Fox
Usually remembered for its slogan \"Tippecanoe and Tyler too,\" the
election of 1840 is also the first presidential election of which
it might be truly said, \"It’s the Economy, Stupid.\" Tackling a
contest best known for log cabins, cider barrels, and catchy songs,
this timely volume reveals that the election of 1840 might be
better understood as a case study of how profoundly the economy
shapes the presidential vote. Richard J. Ellis, a veteran scholar
of presidential politics, suggests that the election pitting the
Democratic incumbent Martin Van Buren against Whig William Henry
Harrison should also be remembered as the first presidential
election in which a major political party selected-rather than
merely anointed-its nominee at a national nominating convention. In
this analysis, the convention's selection, as well as Henry Clay's
post-convention words and deeds, emerge as crucial factors in the
shaping of the nineteenth-century partisan nation. Exploring the
puzzle of why the Whig Party's political titan Henry Clay lost out
to a relative political also-ran, Ellis teases out the role the
fluctuating economy and growing anti-slavery sentiment played in
the party's fateful decision to nominate the Harrison-Tyler ticket.
His work dismantles the caricature of the 1840 campaign (a.k.a. the
\"carnival campaign\") as all froth and no substance, instead giving
due seriousness to the deeply held moral commitments, as well as
anxieties about the political system, that informed the campaign.
In Old Tip vs. the Sly Fox , the campaign of 1840 can
finally be seen clearly for what it was: a contest of two
profoundly different visions of policy and governance, including
fundamental, still-pressing questions about the place of the
presidency and Congress in the US political system.
eBook
Facing China : truth and memory in portraiture
'Facing China' is an exploration of the portrait arts in China from the dynastic to the modern and contemporary, in painting, sculpture, photography, and video. It focuses on truth and memory in the portraiture process, from encounters between subject, portrait, and artist, to broader familial, social, and political arenas. It also examines the influence of location on portrait production, reception, and display, from tombs, ancestral shrines, temples, gardens, and palace halls to public and private spaces.
BOOK
JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at z ∼ 7–14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe
We present the number densities and physical properties of the bright galaxies spectroscopically confirmed at z ∼ 7–14. Our sample is composed of 60 galaxies at zspec ∼ 7–14, including recently confirmed galaxies at zspec = 12.34–14.18 with JWST, as well as new confirmations at zspec = 6.583–7.643 with −24 < MUV < −21 mag using ALMA and Keck. Our JWST/NIRSpec observations have also revealed that very bright galaxy candidates at z ∼ 10–13 identified from ground-based telescope images before JWST are passive galaxies at z ∼ 3–4, emphasizing the necessity of strict screening and spectroscopy in the selection of the brightest galaxies at z > 10. The UV luminosity functions derived from these spectroscopic results are consistent with a double power-law function, showing tensions with theoretical models at the bright end. To understand the origin of the overabundance of bright galaxies, we investigate their morphologies using JWST/NIRCam high-resolution images obtained in various surveys, including PRIMER and COSMOS-Web. We find that ∼70% of the bright galaxies at z ∼ 7 exhibit clumpy morphologies with multiple subcomponents, suggesting merger-induced starburst activity, which is consistent with SED fitting results showing bursty star formation histories. At z ≳ 10, bright galaxies are classified into two types of galaxies: extended ones with weak high-ionization emission lines, and compact ones with strong high-ionization lines including N iv]λ1486, indicating that at least two different processes (e.g., merger-induced starburst and compact star formation/AGN) are shaping the physical properties of the brightest galaxies at z ≳ 10 and are responsible for their overabundance.
Journal Article