This paper discusses peculiarities of the great mid-latitude aurora that occurred during the extreme magnetic storm on February 11, 1958. This mid-latitude aurora had unusual optical and spectral ...characteristics, among which, first of all, were very high (10⁵–10⁸ R) intensities of atomic oxygen OI 630.0 nm emission and an unusually high ratio of the intensities of two forbidden lines of oxygen OI 630.0 nm and 557.7 nm (I₆₃₀/I₅₅₇.₇). In some points, this ratio was as high as 10³–10⁴. Analysis of I₆₃₀ dynamics during other extreme geomagnetic storms and associated geophysical conditions and physical processes in Earth’s ionosphere and magnetosphere allows us to assume that great mid-latitude auroras are formed during intense substorms in main phases of magnetic storms. In order to interpret the observed features of the February 11, 1958 mid-latitude aurora, we propose to examine the mechanism of level OI ¹D selective filling in which reactions of resonance recharge of oxygen ions O⁺(²D)+O (³P)→O⁺(⁴S)+O(³P, ¹D) and/or reactions of oxygen atom and molecule collisions with excited components of odd nitrogen can be implemented.
"Concern about the climate crisis is widespread as humans struggle to navigate life in uncertain times. From the vantage of a schooner full of artists on an adventure in the high Arctic, biologist ...Lynne Quarmby explains the science that convinced her of an urgent need to act on climate change and recounts how this knowledge--and the fear and panic it elicited--plunged her into unsustainable action, ending in arrests, lawsuits, and a failed electoral campaign on behalf of the Green Party of Canada. Watermelon Snow weaves memoir, microbiology, and artistic antics together with descriptions of a sublime Arctic landscape. At the top of the warming world, Quarmby struggles with burnout and grief while an aerial artist twirls high in the ship's rigging, bearded seals sing mournfully, polar bears prowl, and glaciers crumble into the sea. In a compelling narrative, sorrow and fear are balanced by beauty and wonder. The author's journey back from a life out of balance includes excursions into evolutionary history where her discoveries reveal the heart of human existence. The climate realities are as dark as the Arctic winter, yet this is a book of lightness and generosity. Quarmby's voice, intimate and original, illuminates the science while offering a reminder that much about the human experience is beyond reason. Inspiring and deeply personal, Watermelon Snow is the story of one scientist's rediscovery of what it means to live a good life at a time of increasing desperation about the future."--
Doris Salcedo, a Colombian-born artist, addresses the politics of memory and forgetting in work that embraces fraught situations in dangerous places. Noted critic and theorist Mieke Bal narrates ...between the disciplines of contemporary culture in order to boldly reimagine the role of the visual arts. Both women are pathbreaking figures, globally renowned and widely respected. Doris Salcedo, meet Mieke Bal. In Of What One Cannot Speak, Bal leads us into intimate encounters with Salcedo’s art, encouraging us to consider each work as a “theoretical object” that invites—and demands—certain kinds of considerations about history, death, erasure, and grief. Bal ranges widely through Salcedo’s work, from Salcedo’s Atrabiliarios series—in which the artist uses worn shoes to retrace los desaparecidos (“the disappeared”) from nations like Argentina, Chile, and Colombia—to Shibboleth, Salcedo’s once-in-a-lifetime commission by the Tate Modern, for which she created a rupture, as if by earthquake, that stretched the length of the museum hall’s concrete floor. In each instance, Salcedo’s installations speak for themselves, utilizing household items, human bones, and common domestic architecture to explore the silent spaces between violence, trauma, and identity. Yet Bal draws out even deeper responses to the work, questioning the nature of political art altogether and introducing concepts of metaphor, time, and space in order to contend with Salcedo’s powerful sculptures and installations. An unforgettable fusion of art and essay, Of What One Cannot Speak takes us to the very core of events we are capable of remembering—yet still uncomfortably cannot speak aloud.
With each day that passed after the 2003 invasion, the United States seemed to sink deeper in the treacherous quicksand of Iraq's social discord, floundering in the face of deep ethno-sectarian ...divisions that have impeded the creation of a viable state and the molding of a unified Iraqi identity. Yet as Adeed Dawisha shows in this superb political history, the story of a fragile and socially fractured Iraq did not begin with the American-led invasion--it is as old as Iraq itself.
Dawisha traces the history of the Iraqi state from its inception in 1921 following the collapse of the Ottoman Empire and up to the present day. He demonstrates how from the very beginning Iraq's ruling elites sought to unify this ethnically diverse and politically explosive society by developing state governance, fostering democratic institutions, and forging a national identity. Dawisha, who was born and raised in Iraq, gives rare insight into this culturally rich but chronically divided nation, drawing on a wealth of Arabic and Western sources to describe the fortunes and calamities of a state that was assembled by the British in the wake of World War I and which today faces what may be the most serious threat to survival that it has ever known.
Featuring Dawisha's insightful new afterword on recent political developments,Iraqis required reading for anyone seeking to make sense of what's going on in Iraq today, and why it has been so difficult to create a viable government there.
Continuous turnover of neurons in the olfactory bulb is implicated in several key aspects of olfaction. There is a dramatic decline postnatally in the number of migratory neuroblasts en route to the ...olfactory bulb in humans, and it has been unclear to what extent the small number of neuroblasts at later stages contributes new neurons to the olfactory bulb. We have assessed the age of olfactory bulb neurons in humans by measuring the levels of nuclear bomb test-derived 14C in genomic DNA. We report that 14C concentrations correspond to the atmospheric levels at the time of birth of the individuals, establishing that there is very limited, if any, postnatal neurogenesis in the human olfactory bulb. This identifies a fundamental difference in the plasticity of the human brain compared to other mammals.
► Carbon dating establishes cell turnover dynamics in the human olfactory bulb ► The yearly exchange rate of nonneuronal cells is 2.0%–3.4% ► Olfactory bulb neurons are as old as the individual ► <1% of olfactory bulb neurons are exchanged over 100 years in humans
Bergmann et al. measure the cellular integration of 14C in olfactory bulb neurons from humans exposed to nuclear bomb tests. Results show that olfactory bulb neurons in humans are as old as the individual and argue that adult olfactory bulb neurogenesis is minimal in humans.
Disadvantaged socio-economic position (SEP) in childhood is associated with increased adult mortality and morbidity. We aimed to establish whether childhood SEP was associated with differential ...methylation of adult DNA.
Forty adult males from the 1958 British Birth Cohort Study were selected from SEP extremes in both early childhood and mid-adulthood. We performed genome-wide methylation analysis on blood DNA taken at 45 years using MeDIP (methylated DNA immunoprecipitation). We mapped in triplicate the methylation state of promoters of approximately 20,000 genes and 400 microRNAs. Probe methylation scores were averaged across triplicates and differential methylation between groups of individuals was determined. Differentially methylated promoter sites of selected genes were validated using pyrosequencing of bisulfite-converted DNA.
Variably methylated probes (9112 from n = 223,359 on the microarray) corresponded to 6176 gene promoters with at least one variable probe. Unsupervised hierarchical clustering of probes obtained from the 500 most variable promoters revealed a cluster enriched with high SEP individuals confirming that SEP differences contribute to overall epigenetic variation. Methylation levels for 1252 gene promoters were associated with childhood SEP vs 545 promoters for adulthood SEP. Functionally, associations with childhood SEP appear in promoters of genes enriched in key cell signalling pathways. The differentially methylated promoters associated with SEP cluster in megabase-sized regions of the genome.
Adult blood DNA methylation profiles show more associations with childhood SEP than adult SEP. Organization of these associations across the genome suggests a well-defined epigenetic pattern linked to early socio-economic environment.
When Charles de Gaulle declared that “it is because we are no longer a great power that we need a grand policy," he neatly summarized France’s predicament on the world scene. In this compact and ...engaging history, author Frédéric Bozo deftly recounts France’s efforts to reconcile its proud history and global ambitions with a realistic appraisal of its capabilities, from the aftermath of World War II to the present. He provides insightful analysis of the nation’s triumphs and setbacks through the years of decolonization, Cold War maneuvering, and European unification, as well as the more contemporary challenges posed by an increasingly multipolar and interconnected world.
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