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The stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) and total mercury concentrations (THg) of the three marine catfish species Aspistor luniscutis, Bagre bagre and Genidens genidens were evaluated to understand their trophic relationship in northern Rio de Janeiro state, south-eastern Brazil. The δ13C was similar among the three marine catfishes, whereas δ15N was similar in A. luniscutis and B. bagre and lower in G. genidens. THg was higher in G. genidens and lower in B. bagre. The greater assimilation of Sciaenidae fishes and squids by A. luniscutis and B. bagre resulted in smaller isotopic niche areas and trophic diversity but higher isotopic niche overlap, trophic redundancy and evenness. For G. genidens, the similar assimilation of all prey items resulted in the broadest isotopic niche among the marine catfishes. The higher mercury content in G. genidens is consistent with an increased important contribution of prey with a higher Hg burden. The bioaccumulation process was indicated by significant correlations of δ15N and THg with total length and total mass. Additionally, a significant correlation between THg and δ15N reflected the biomagnification process through the food web.
Green biorefineries provide novel opportunities to use the green biomass efficiently and utilize the ecosystem services provided by grasslands more widely. The effects of the inclusion of fractionated grass silage solid fraction (pulp) on feed intake, rumen fermentation, diet digestion and milk production in dairy cows were investigated. Pulp was separated from grass silage using a screw press simulating a green biorefinery. Partial removal of liquid from forage increased DM concentration from 220 to 432 g/kg and NDF from 589 to 709 g/kg DM while CP decreased from 144 to 107 g/kg DM. A feeding trial using an incomplete changeover design with 24 Nordic Red cows and two 3-week periods was conducted. The pulp replaced grass silage in the diet at 0 (P0), 25 (P25) and 50 (P50) percentage of total forage, which was fed ad libitum with 13 kg of concentrate for all treatments. The forage DM intake was highest on P25 (14.1 kg/day) while P0 and P50 did not differ from each other (13.2 and 13.0 kg/day, respectively). There were no differences between the treatments in rumen pH or ammonia N, but the proportion of acetate increased with increasing pulp inclusion. The digestibility was measured using acid insoluble ash and indigestible NDF (iNDF) as internal markers. Neither of the markers detected differences in NDF digestibility, but according to iNDF, apparent total tract organic matter digestibility decreased with increasing pulp inclusion. The cows maintained milk production at P25, but it showed some decline at P50 (energy-corrected milk at P0 and P25 was 39.8 kg/day while for P50, it was 38.5 kg/day, P = 0.056) and the milk protein yield significantly declined with higher pulp inclusion. Simultaneously, the nitrogen use efficiency in milk production increased. It seems that the fibrous grass-based fraction from a biorefinery process has potential to be used as a feed for ruminants.
This paper presents new descriptions of Anacardiaceae fossil woods from the Ituzaingó Formation (late Cenozoic) at the Toma Vieja, Curtiembre, and Arroyo El Espinillo localities, Argentina. We describe eight silicified woods assigned to four different species in three genera, one of which, Parametopioxylon crystalliferum n. gen. n. sp., is new. Similarities between these three genera and the six Anacardiaceae species previously recorded from the late Cenozoic in northeastern Argentina are investigated using multivariate analysis techniques (correspondence and cluster analysis). Our study is based on 33 characters scored for 17 fossil specimens (10 Astroniumxylon Brea, Aceñolaza, and Zucol 2001; five Schinopsixylon Lutz, 1979; and two Parametopioxylon n. gen.) and four extant species (Astronium balansae Engl., Astronium urundeuva Engl., Schinopsis balansae Engl., and Metopium sp.). Our main goal is to determine the wood anatomical features useful for distinguishing among these species. Results of the multivariate analyses support the previous classification where Schinopsixylon is distinguished from Astroniumxylon by having exclusively paratracheal axial parenchyma, ≥30% multiseriate rays, and multiseriate rays that are ≥5 cells wide and commonly 301–400 μm in height. Additionally, we propose that Schinopsixylon heckii Lutz, 1979 is synonymous with S. herbstii Lutz, 1979. A diagnostic key for the fossil species studied is given. Wood anatomy of Anacardiaceae fossil woods from Argentina (late Cenozoic) suggests a warm, dry to semi-humid climate for this region, supporting previous studies.
We study a model in which parents care about the economic and social status of their offspring. The chances of an individual achieving social status depends on innate traits, that is, IQ, ability, social and cultural environment, and other price-insensitive endowments, passed on by their parents, on human capital investments and on chance events. Parents can, through human capital investments, increase the offspring’s probability of climbing the social ladder, although they cannot borrow against the children’s perspective earning. Consequently, income and trait heterogeneity are the determinants of unequal opportunities and of intergenerational mobility.
The tomato Mi-1 gene mediates plant resistance to whitefly Bemisia tabaci, nematodes, and aphids. Other genes are also required for this resistance, and a model of interaction between the proteins encoded by these genes was proposed. Microarray analyses were used previously to identify genes involved in plant resistance to pests or pathogens, but scarcely in resistance to insects. In the present work, the GeneChip™ Tomato Genome Array (Affymetrix®) was used to compare the transcriptional profiles of Motelle (bearing Mi-1) and Moneymaker (lacking Mi-1) cultivars, both before and after B. tabaci infestation. Ten transcripts were expressed at least twofold in uninfested Motelle than in Moneymaker, while other eight were expressed half or less. After whitefly infestation, differences between cultivars increased to 14 transcripts expressed more in Motelle than in Moneymaker and 14 transcripts less expressed. Half of these transcripts showed no differential expression before infestation. These results show the baseline differences in the tomato transcriptomic profile associated with the presence or absence of the Mi-1 gene and provide us with valuable information on candidate genes to intervene in either compatible or incompatible tomato–whitefly interactions.
This paper presents a theoretical and experimental study of the long-standing fluid mechanics problem involving the temporal resolution of a large localised initial disturbance into a sequence of solitary waves. This problem is of fundamental importance in a range of applications, including tsunami and internal ocean wave modelling. This study is performed in the context of the viscous fluid conduit system – the driven, cylindrical, free interface between two miscible Stokes fluids with high viscosity contrast. Owing to buoyancy-induced nonlinear self-steepening balanced by stress-induced interfacial dispersion, the disturbance evolves into a slowly modulated wavetrain and further into a sequence of solitary waves. An extension of Whitham modulation theory, termed the solitary wave resolution method, is used to resolve the fission of an initial disturbance into solitary waves. The developed theory predicts the relationship between the initial disturbance’s profile, the number of emergent solitary waves and their amplitude distribution, quantifying an extension of the well-known soliton resolution conjecture from integrable systems to non-integrable systems that often provide a more accurate modelling of physical systems. The theoretical predictions for the fluid conduit system are confirmed both numerically and experimentally. The number of observed solitary waves is consistently within one to two waves of the prediction, and the amplitude distribution shows remarkable agreement. Universal properties of solitary wave fission in other fluid dynamics problems are identified.
Mexico ranks first in childhood obesity worldwide. However, little is known about the factors influencing maternal feeding practices. The present study aimed to estimate the prevalence of feeding practices and explore associations between weight concern, weight perception, sociodemographic characteristics and those feeding practices.
Mothers aged ≥18 years who were in charge of feeding a singleton child aged 2–6 years with no endocrine disease or visible genetic malformations (n 507). Information on six maternal feeding practices, concern and perception of the child’s weight and demographics were collected by interview. The mother’s and child’s height and weight were measured. The feeding practices questionnaire was subject to content, construct and convergent validity analysis. Then, mean feeding scores were obtained and prevalence and 95 % CI were determined for scores ≥3; multivariate logistic regression was performed.
Not modelling (63·5 %; 95 % CI 59·2, 67·8 %) and pressuring to eat (55·6 %; 95 % CI 51·2, 60·0 %) were the most frequent feeding practices, followed by easy access to unhealthy foods (45·4 %; 95 % CI 40·9, 49·8 %) and child control (43·2 %; 95 % CI 38·8, 47·6 %). They prevailed despite concern about the child’s excess weight or a perception of the child as overweight/obese. Education was associated with the highest number of practices (educated mothers used more pressuring to eat, less regulation and less easy access; or monitoring was less absent).
The frequency of certain feeding practices needs to be improved. Emphasis on the child’s weight concern, obesity perception and maternal education is essential for optimizing intervention planning.
This proposed contribution to the special issue of ILWCH offers a theoretical re-consideration of the Liberian project. If, as is commonly supposed in its historiography and across contemporary discourse regarding its fortunes into the twenty-first century, Liberia is a notable, albeit contested, instance of the modern era's correctable violence in that it stands as an imperfect realization of the emancipated slave, the liberated colony, and the freedom to labor unalienated, then such representation continues to hide more than it reveals. This essay, instead, reads Liberia as an instructive leitmotif for the conversion of racial slavery's synecdochical plantation system in the Americas into the plantation of the world writ large: the global scene of antiblackness and the immutable qualification for enslavement accorded black positionality alone. Transitions between political economic systems—from slave trade to “re-colonization,” from Firestone occupation to dictatorial-democratic regimes—reemerge from this re-examination as crucial but inessential to understanding Liberia's position, and thus that of black laboring subjects, in the modern world. I argue that slavery is the simultaneous primitive accumulation of black land and bodies, but that this reality largely escapes current conceptualization of not only the history of labor but also that of enslavement. In other words, the African slave trade (driven first by Arabs in the Indian Ocean region, then Europeans in the Mediterranean, and, subsequently, Euro-Americans in the Atlantic) did not simply leave as its corollary effect, or byproduct, the underdevelopment of African societies. The trade in African flesh was at once the co-production of a geography of desire in which blackness is perpetually fungible at every scale, from the body to the nation-state to its soil—all treasures not simply for violation and exploitation, but more importantly, for accumulation and all manner of usage. The Liberian project elucidates this ongoing reality in distinctive ways—especially when we regard it through the lens of the millennium-plus paradigm of African enslavement. Conceptualizing slavery's “afterlife” entails exploring the ways that emancipation extended, not ameliorated, the chattel condition, and as such, impugns the efficacy of key analytic categories like “settler,” “native,” “labor,” and “freedom” when applied to black existence. Marronage, rather than colonization or emancipation, situates Liberia within the intergenerational struggle of, and over, black work against social death. Read as enslavement's conversion, this essay neither impugns nor heralds black action and leadership on the Liberian project at a particular historical moment, but rather agitates for centering black thought on the ongoing issue of black fungibility and social captivity that Liberia exemplifies. I argue that such a reading of Liberia presents a critique of both settler colonialism and of a certain conceptualization of the black radical tradition and its futures in heavily optimist, positivist, and political economic terms that are enjoying considerable favor in leading discourse on black struggle today.
During the US military occupation of Haiti, domestic workers performed the crucial labor that allowed Marine households, the city of Port-au-Prince, and the entire country to function. In this sense, they represented a human infrastructure for the entire occupation. Their experiences show that the debates over labor, race, and sovereignty that defined the high politics of the occupation actually reached into private spaces where face-to-face interactions between occupier and occupied occurred. Domestic work, like other types of labor in the occupation, ran the gamut from highly coerced forms of unpaid child labor and convict work to various configurations of wage labor. Domestic sites influenced mutual processes of race-making, including the US exoticist obsession with Haitian Vodou. Servants’ conflicts with their Marine employers included—but ultimately went beyond—daily struggles over labor. Their proximity to marines influenced domestics’ participation in acts of anti-imperial activism, such as the Caco rebellion, and explains why servants were invoked by radical journalists and cultural nationalist writers who opposed US rule. Domestics’ activities also highlight under-explored areas of Haitian activism, such as their use of formal state institutions to seek redress and their participation in emerging forms of urban protest that included other members of the urban working class. Although novel and relatively small during the occupation, such urban protests have become a staple of Haitian politics in the present day.
During the first three decades of the twentieth century, a cluster of self-educated workers that called themselves obreros ilustrados (enlightened workers) sought to dominate the means of knowledge production, reproduction, and documentation. The discourses produced by this group of working-class intellectuals did not challenge but complemented the elite's contempt towards the laboring masses. In order to be legible in the “Archive of Puertorriqueñidad”—an archive crossed by centuries of colonialism, slavery, and imperial violence—these ragged intellectuals created various layers of exclusions that silenced those individuals that unapologetically upheld their Blackness. These silencing practices not only had power in the moment in which they took place but also influenced later historical production. To explore these dynamics, this paper uses the stories of Juana Colón and Mateo Pérez Sanjurjo. Both were highly-respected Black illiterate labor organizers that were absent in the historical narratives obreros ilustrados wrote about the labor movement. Ultimately, this article seeks to create counterarchives by unearthing, imagining, and retelling the lives of those that were not deemed worthy of being represented in the historical record.
This article examines Cuba's long process of gradual emancipation (from 1868–1886) and the continual states of bondage that categorize the afterlife of Cuban slavery. The article addresses deferred freedom, re-enslavement, and maintenance of legal states of bondage in the midst of “freedom.” It contends with the legacy of the casta system, the contradictions within the Moret Law of 1870, which “half-freed” children but not their mothers, and it analyzes the struggle for full emancipation after US occupation, with the thwarted attempt of forming the Partido Independiente de Color to enfranchise populations of color. The article argues that the desire to control the labor of racialized populations, and in particular the labor of black and indigenous women and children, unified Cuban and US slaveholders determined to detain emancipation; and provides an analysis of the re-enslavement of US free people of color at the end of the nineteenth century, kidnapped and brought to the Cuba as a method of bolstering slavery. The article draws on the scholarship of Saidiya Hartman and Shona Jackson to provide an assessment of the afterlife of Cuban slavery, the invisibility of indigenous labor, the hypervisibility of African labor in the Caribbean deployed to maintain white supremacy, and it critiques the humanizing narrative of labor as a means for freedom in order to address the ways in which, for racialized populations in Cuba, wage labor would emerge as a tool of oppression. The article raises an inquiry into the historiography on Cuban slavery to provide a critique of the invisibility of indigenous and African women and children. It also considers the role and place of sexual exchanges/prostitution utilized to obtain freedom and to finance self-manumission, alongside the powerful narratives of the social and sexual deviancy of black women that circulated within nineteenth-century Cuba.
“The Abstract Slave: Anti-Blackness and Marx's Method” presents an immanent critique of the Marxist value-form. While Marx could historically think the empirical reality of slavery appearing together with capitalism, the value-form theoretically unthinks the significance of the conjuncture slavery and capitalism. Even with attempts to recuperate Marxism from some of the errors of evolutionism, the content and form of slavery is not usually up for debate, only the status of its interaction with capitalist circuits (a rearrangement of difference within unity). Mirroring the Marxist methodology of rising from the “abstract” to the “concrete,” this article moves to substitute the abstraction of labor with that of slavery and closes by restaging the concrete development of “real subsumption” through the problem of abolition. Such a substitution deconstructs Marx's method by situating slavery's transposition to brute force (and race's reduction to false consciousness) as the productive source of the capitalist form of value.
This paper examines the 1941 pamphlet “Down with Starvation-Wages!,” written by Local 313 striking sharecroppers in Southeast Missouri, as it both anticipates and places into deep historical tension theories of normativity that would come to be associated with continental European critique after World War Two. The pamphlet's contents are both a local response to and critical theory of New Deal struggles over the meaning and bureaucratic administration of rehabilitation. I first examine the schematic history of federal Rehabilitation programs as they emerged in the biomedical context of the First World War and were then transformed in the agricultural-economic context of the New Deal era. Across these contexts, I demonstrate that their main discursive and procedural function was the cultivation of their white beneficiaries as economic and political self-sovereigns. I then argue that the brief attempt to extend this Agricultural Adjustment Administration-administered form of Rural Rehabilitation programming, ostensibly an index of citizenship, to 1939 striking sharecroppers constituted one attempt to dull the normative force of an organized population, which had long been treated as surplus. I outline the relocation of remaining protesters to the farming cooperative of Cropperville by the St. Louis Committee for the Rehabilitation of Sharecroppers as an intermediary mode of social management that aimed to prevent organized sharecropper protest without extending the promise of full citizenship. The Local's 1941 subsequent “starvation-wage” is thus a relational theory of racist exploitation that allowed the state of starvation to emerge among black persons. In its maintenance of various orders of black persons’ virtual value as perpetually unrealized, its economy is made to run through cycles of starvation, bondage, and debt; as well as nutrition, rehabilitation, and repair. The Local's subsequent endorsement of the 1941 strike and of coalitional organizing with white sharecroppers thus instrumentalizes the very uneven racist distribution of history and life chances by the starvation-wage as a political resource in elaborating potentially novel arrangements of life.
This article follows the “convict clause” in the Thirteenth Amendment to the US Constitution – the exception for slavery and involuntary servitude to continue as punishment for crime – to the Panamá Canal Zone. It argues that US officials used the prison system not only to extract labor, but to structure racial hierarchy and justify expansionist claims to jurisdiction and sovereignty. It reveals how despite the purported “usefulness” of the Black bodies conscripted in this brutal labor regime, the prison system's operational modality was racial and gendered violence which exceeded the registers of political economy, penology, and state-building in which that usefulness was framed. The Canal Zone convict road building scheme then became a cornerstone from which Good Roads Movement boosters, who claimed the convict was a slave of the state, could push for the Pan-American Highway across the hemisphere. Afro-Panamanian and Caribbean workers, who were the majority of those forced into Canal Zone chain gangs, protested the racism and imperialism of the prison system by blending anti-colonial and anti-racist strategies and deploying a positive notion of blackness as solidarity and race pride. Their efforts and insight offer an understanding of the US carceral state's imperial dimensions as well as enduring lessons for movements struggling to broaden the meaning and experience of freedom in the face of slavery's recurrent afterlives.
Louise Audino Tilly, who died on March 2, 2018, enjoyed a relatively short twenty-five year career as a historian. But Tilly left an enduring imprint through her example and through her scholarship on the history of women and work, on the social and economic circumstances affecting collective action, and on the connections between demographic changes and family life. In more recent decades, several generations of historians have benefitted from the road maps she left pointing the way for emerging work on the connections between micro-level analysis and national and international histories of social change.