Juvenile Chinook salmon (Oncorhynchus tshawytscha) residency and early growth in the lower Fraser River estuary

The Fraser River has historically supported the most abundant salmon runs in North America, which have been declining for decades. Despite its importance and ongoing threats of climate change and habitat degradation, the Fraser River estuary is particularly understudied, with the latest comprehensive fish survey occurring in the early 1980s. We were particularly interested in the role of estuarine habitat in supporting juvenile salmon during the critical outmigration period. As part of a two-year study, which surveyed 20 sites in the lower estuary across three habitat types, we sampled over 3,000 juvenile Chinook salmon. We caught the majority of all salmon in the marsh habitat in both 2016 and 2017, despite large differences in seasonal flows, temperatures and previous escapement. In 2016 we retained a subsample of 264 Chinook salmon for genetic and growth analyses. The vast majority of these (237) were identified by the Pacific Biological Station as lower Fraser Chinook (Harrison or Chilliwack stock), which produce the highest proportion of fall-run, ocean type Chinook in the Salish Sea. Using a combination of visual and chemical analyses of the otoliths using LA-ICPMS, we can assess the precise entry timing of these fish into the estuary, and measure their estuarine growth. In our preliminary results, we have found diverse entry and residency times among these fish of presumed similar life history strategy. Importantly, we can detect an elemental signature for marine entry in fish that have been in the estuary for a short time, which indicates that studies focusing on Chinook at later time points may be attributing estuarine growth to marine growth. Our results will help us determine the importance of the lower estuary in the marine survival of these Chinook populations, and provide some insight into life history trade-offs for ocean type juveniles

Political Protest in Japan, Part II 戦間期日本の政治的抗議活動 (下）

Between 2002 and 2013, the Visualizing Cultures (VC) project at M.I.T. produced a number of “image-driven” online units addressing Japan and China in the modern world. Co-directed by John Dower and Shigeru Miyagawa, VC tapped a wide range of hitherto largely inaccessible visual resources of an historical nature. Each topical treatment—which can run from one to as many as four separate units—formats and analyzes these graphics in ways that, ideally, open new windows of understanding for scholars, teachers, and students. VC endorses the “creative commons” ideal, meaning that everything on the site, including all images, can be downloaded and reproduced for educational (but not commercial) uses. Funding and staffing for VC formally ended in 2013, with around eight topical treatments still in the pipes. These will eventually go online. Overall, including the treatments to come, the project includes a total of fifty-five individual units covering twenty-six different subjects. The China-Japan division will be roughly equitable when everything is in place. (There will also be a two-part treatment of the U.S. and the Philippines between 1898 and 1912.) The full VC menu can be accessed at visualizingcultures.mit.edu. VC is closing shop for the production of new units at a moment when it was just reaching a “critical mass” of subjects that invite crisscrossing among separate topical treatments. Western imperialist expansion beginning with the Canton trade system, first Opium War, and Commodore Matthew Perry’s “opening” of Japan is potentially one such subject; comparing and contrasting Japanese and Chinese engagements with “the West” is another. The VC units draw vivid attention to political, cultural, and technological transformation in East Asia between the mid-19th and mid-20th century. Many of them highlight graphic expressions of militarism, nationalism, racism, and anti-foreignism. Because the visual resources tapped for these units range from high art to popular culture, and are especially strong in the latter, it is now possible to tap the site to explore the emergence of consumer cultures and mass audiences in Japan and China. This, in turn, calls attention to popular cultures and grassroots activities in general. One example of the insights to be gained by approaching the VC menu with this comparative perspective in mind is the subject of popular protest in Japan. That is the common thrust of the four separate VC units introduced here. This is, of course, a pertinent subject today, when the mass media in the Anglophone world tends to portray Japan as a fundamentally homogeneous, consensual, harmonious, conflict-averse and risk-averse “culture” (a familiar rendering, for example, in the venerable New York Times). No serious historian of modern Japan would endorse these canards, which carry echoes of the “beautiful customs” nostrums of Japan’s own nationalistic ideologues. At the same time, however, it cannot be denied that the past four decades or so have seen nothing comparable in intensity or scale to the popular protests in prewar Japan, or the demonstrations and “citizens’ movements” (shimin undō) that took place in postwar Japan up to the early 1970s. How can we place all this in perspective? The image-driven VC explorations of protest in Japan begin in 1905 and end with the massive “Ampō” demonstrations against revision of the U.S.-Japan mutual security treaty in 1960. The four treatments that will be reproduced in The Asia-Pacific Journal beginning in this issue are as follows: 1. Social Protest in Imperial Japan: The Hibiya Riot of 1905, by Andrew Gordon. We reprint this article with this introduction. Other articles will follow in the coming months. 2. Political Protest in Interwar Japan: Posters & Handbills from the Ohara Collection (1920s~1930s), by Christopher Gerteis (in two units). See Part I here. 3. Protest Art in 1950s Japan: The Forgotten Reportage Painters, by Linda Hoaglund. 4. Tokyo 1960: Days of Rage & Grief: Hamaya Hiroshi’s Photos of the Anti-Security-Treaty Protests, by Justin Jesty. VC and the Asia-Pacific Journal are committed to bringing the highest quality visual images to the classroom. In establishing this partnership, we anticipate publishing the subsequent units on protest every two weeks. We hope to follow this up with new units in preparation and projected. John W. Dower is emeritus professor of history at the Massachusetts Institute of Technology. His books include Empire and Aftermath: Yoshida Shigeru and the Japanese Experience, 1878-1954 (1979); War Without Mercy: Race and Power in the Pacific War (1986); Embracing Defeat: Japan in the Wake of World War II (1999); Cultures of War: Pearl Harbor / Hiroshima / 9-11 / Iraq (2010); and two collections of essays: Japan in War and Peace: Selected Essays (1994), and Ways of Forgetting, Ways of Remembering: Japan in the Modern World (2012)

RasGRP1 Transduces Low-Grade TCR Signals which Are Critical for T Cell Development, Homeostasis, and Differentiation

AbstractTwo important Ras-guanyl nucleotide exchange factors, Sos and RasGRP1, control Ras activation in thymocytes. However, the relative contribution of these two exchange factors to Ras/ERK activation and their resulting impact on positive and negative selection is unclear. We have produced two lines of RasGRP1−/− TCR transgenic mice to determine the effect of RasGRP1 in T cell development under conditions of defined TCR signaling. Our results demonstrate that RasGRP1 is crucial for thymocytes expressing weakly selecting TCRs whereas those that express stronger selecting TCRs are more effective at utilizing RasGRP1-independent mechanisms for ERK activation and positive selection. Analysis of RasGRP1−/− peripheral T cells also revealed hitherto unidentified functions of RasGRP1 in regulating T cell homeostasis and sustaining antigen-induced developmental programming

Human Consumption of Microplastics

Microplastics are ubiquitous across ecosystems, yet the exposure risk to humans is unresolved. Focusing on the American diet, we evaluated the number of microplastic particles in commonly consumed foods in relation to their recommended daily intake. The potential for microplastic inhalation and how the source of drinking water may affect microplastic consumption were also explored. Our analysis used 402 data points from 26 studies, which represents over 3600 processed samples. Evaluating approximately 15% of Americans’ caloric intake, we estimate that annual microplastics consumption ranges from 39000 to 52000 particles depending on age and sex. These estimates increase to 74000 and 121000 when inhalation is considered. Additionally, individuals who meet their recommended water intake through only bottled sources may be ingesting an additional 90000 microplastics annually, compared to 4000 microplastics for those who consume only tap water. These estimates are subject to large amounts of variation; however, given methodological and data limitations, these values are likely underestimates

The Erotic and the Vulgar: Visual Culture and Organized Labor's Critique of U.S. Hegemony in Occupied Japan

This essay engages the colonial legacy of postwar Japan by arguing that the political cartoons produced as part of the postwar Japanese labor movement’s critique of U.S. cultural hegemony illustrate how gendered discourses underpinned, and sometimes undermined, the ideologies formally represented by visual artists and the organizations that funded them. A significant component of organized labor’s propaganda rested on a corpus of visual media that depicted women as icons of Japanese national culture. Japan’s most militant labor unions were propagating anti-imperialist discourses that invoked an engendered/endangered nation that accentuated the importance of union roles for men by subordinating, then eliminating, union roles for women

Life in the fast lane: Revisiting the fast growth—High survival paradigm during the early life stages of fishes

Early life survival is critical to successful replenishment of fish populations, and hypotheses developed under the Growth-Survival Paradigm (GSP) have guided investigations of controlling processes. The GSP postulates that recruitment depends on growth and mortality rates during early life stages, as well as their duration, after which the mortality declines substantially. The GSP predicts a shift in the frequency distribution of growth histories with age towards faster growth rates relative to the initial population because slow-growing individuals are subject to high mortality (via starvation and predation). However, mortality data compiled from 387 cases published in 153 studies (1971–2022) showed that the GSP was only supported in 56% of cases. Selection against slow growth occurred in two-thirds of field studies, leaving a non-negligible fraction of cases showing either an absence of or inverse growth-selective survival, suggesting the growth-survival relationship is more complex than currently considered within the GSP framework. Stochastic simulations allowed us to assess the influence of key intrinsic and extrinsic factors on the characteristics of surviving larvae and identify knowledge gaps on the drivers of variability in growth-selective survival. We suggest caution when interpreting patterns of growth selection because changes in variance and autocorrelation of individual growth rates among cohorts can invalidate fundamental GSP assumptions. We argue that breakthroughs in recruitment research require a comprehensive, population-specific characterization of the role of predation and intrinsic factors in driving variability in the distribution and autocorrelation of larval growth rates, and of the life stage corresponding to the endpoint of pre-recruited life. -- Keywords : critical period ; growth-mortality ; individual characteristics ; larval physiology ; predation ; recruitment endpoint

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference