Leptin signaling pathways, stemming primarily from the hypothalamus, are necessary for maintaining normal energy homeostasis and body weight. In both rodents and humans, dysregulation of leptin signaling leads to morbid obesity and diabetes. Since leptin resistance is considered a primary factor underlying obesity, understanding the regulation of leptin signaling could lead to therapeutic tools and provide insights into the causality of obesity. While leptin actions in some hypothalamic regions such as the arcuate nuclei have been characterized, less is known about leptin activity in the hypothalamic ventromedial nuclei (VMN). Recently, pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to reduce feeding behavior and alter metabolism when administered into the VMN in a pattern similar to that of leptin. In the current study, we examined whether leptin and PACAP actions in the VMN share overlapping pathways in the regulation of energy balance. Interestingly, PACAP administration into the VMN increased STAT3 phosphorylation and SOCS3 mRNA expression, both of which are hallmarks of leptin receptor activation. In addition, BDNF mRNA expression in the VMN was increased by both leptin and PACAP administration. Moreover, antagonizing PACAP receptors fully reversed the behavioral and cellular effects of leptin injections into the VMN. Electrophysiological studies further illustrated that leptin-induced effects on VMN neurons were blocked by antagonizing PACAP receptors. We conclude that leptin dependency on PACAP signaling in the VMN suggests a potential common signaling cascade, allowing a tonically and systemically secreted neuropeptide to be more precisely regulated by central neuropeptides.

How did the 3.5-inch Winchester hard disk drive become the fundamental building block of the modern data center? In attempting to answer this question, I theorize the concept of "data peripheries" to attend to the awkward, uneven, and unintended outsides of data infrastructures. I explore the concept of data peripheries by first situating Big Data in one of its many unintended outsides—an unassuming dog kennel in Indiana housed in a former permanent magnet manufacturing plant. From the perspective of this dog kennel, I then build a history of the 3.5-inch Winchester hard disk drive, and weave this hard drive history through the industrial histories of rare earth mining and permanent magnet manufacturing, focusing principally on Magnequench, a former General Motors subsidiary, and its sale and movement of operations from Indiana to China in the mid-1990s and early 2000s. I then discuss how mobilities of rare earths, both as materials and political discourse, shape Big Data futures, and conclude by speculating on how using the situated lenses of data peripheries (such as this Indiana dog kennel) can open up new methods for studying the material entanglements of Big Data writ large.

Estimates place Bitcoin’s current energy consumption at 141.83 terawatt-hours/year, an amount comparable to Ukraine. While Bitcoin’s energy problem has become increasingly visible in both academic and popular discourse (see Lally et al. 2019), the computational mechanisms through which the Bitcoin network generates coins, proof-of-work, has gone under-examined. This paper interrogates the “work” in proof-of-work systems. What is this work? How can we access its material history? I trace this history through a media archaeology of computational heat, in an attempt to better situate the intimate relationship between information and energy in proof-of-work systems. I argue the “work” in these systems is principally heat-work, and trace its ideological constructions back to nineteenth-century thermodynamic science, and the reframing of doing work as something exhaustible, directional, and irreversible (Prigogine & Stengers 2017; Daggett 2019). I then follow thermodynamic discourse through Cybernetics debates in the 1940s, illustrating how, early in the formation of Information Theory, the heat-work undergirding the functioning of a “bit” was obscured and compartmentalized, allowing information to be productively abstracted apart from its energetic infrastructures (Hayles 1999; Kline 2015). I conclude with a discussion of the heat-work within the Application Specific Integrated Circuit (ASIC), Bitcoin’s principal mining tool, arguing that proof-of-work mining is not a radical exception to the computing status quo, but rather a lens through which to think more broadly about computing’s complex relationship to energy, and ultimately, how this relationship can be different.

There is a digital skills crisis: the digital skills crisis does not exist. Through a conceptual history of skill––a word, concept, and action––this paper analyzes the historical, cultural, and material constructions of skill and how it has come to influence current discourse around the alleged “digital skills crisis”. Rather than an intrinsic quality to be acquired, we show how skill has been deployed as a political concept to order bodies and processes according to the interests of power and capital. Pushing back against skilled/unskilled dichotomies, we argue skill itself has been used as a technology in the division of labor (Marx, 1990) to maintain patriarchal (Berg, 1994), and colonial hierarchies (Kumar, 2018). This genealogy helps situate how skill is conceptually operationalized alongside technology in contemporary politics. Through a systematic analysis of policy and public speech from four US presidents––from Clinton’s push to bridge the “digital divide” to Trump’s executive order to “combat the skills crisis”––we show how skills discourse is framed as a deficit issue in both democratic and republican administrations. By centering the conceptual roots of skill, this paper attempts to reclaim an understanding of skills as collective social knowledge that are essential to, and not separate from, technology (Veblen, 1914). Through this work, we hope to generate a broader discussion about the normative assumptions which tie the idea of skill to technological progress so we may re-imagine the kinds of collective social knowledge we need to produce a more just and equitable future.

No abstract