RATIONALE:Opioid use disorders are marked by both drug use despite negative consequences and drug use to avoid negative physiological and psychological states. The dorsal raphe nucleus (DRN) serotonin (5-HT) system modulates reward- and stress-related responses, but its role in both male and female rats remains incompletely understood. OBJECTIVE:To investigate the role of the DRN 5-HT system in heroin-motivated behaviors in male and female rats, and, in parallel, to examine the impacts of stress-induced reinstatement of heroin seeking on DRN 5-HT cell electrophysiological profiles. METHODS:To probe DRN 5-HT contributions to basal, punished, and stress-driven heroin consumption, we performed chemogenetic manipulations in transgenic Tph2-iCre Sprague-Dawley rats. Twenty-two- and 50-kHz ultrasonic vocalizations (USVs), reflecting negative and positive affective state, respectively, were recorded during basal and punished heroin self-administration and a novel dual stressor-induced reinstatement model to delineate affective profiles. In a separate cohort of conventional Sprague-Dawley rats, ex vivo electrophysiology in DRN 5-HT cells examined the impact of stress-induced reinstatement of heroin seeking on spontaneous inhibitory postsynaptic currents (sIPSCs). RESULTS:Activation of the DRN 5-HT system increased heroin consumption under basal and punished conditions but did not alter stress-induced reinstatement or affective measures. Although females showed higher active lever pressing and consumption of heroin intake during acquisition of self-administration, responses to DRN 5-HT activation did not differ by sex. Ex vivo recordings revealed elevated sIPSCs in DRN 5-HT neurons from post-reinstatement females, but not males, indicating increased inhibitory drive. Notably, chemogenetic viral expression was densest in the dorsal DRN (DRD), associated with anxiety-related behavior, whereas electrophysiological recordings targeted ventrolateral/ventral DRN (DRVL/DRV) regions linked to anxiolysis. CONCLUSIONS:These findings demonstrate a role for the DRN 5-HT system in basal and punished heroin self-administration and a link between stress-induced heroin reinstatement and enhanced GABAergic inhibition of DRN 5-HT neurons in females. Serotonergic involvement in heroin consumption and sex differences in stress-driven heroin seeking patterns may reflect differential engagement of anatomically and functionally distinct DRN subdivisions.
The goal of this study is to determine the geological character and source of the exterior stone stairs that once ascended to the south entry at Stratford Hall on the Potomac River in Virginia. The intent is to clarify the date and physical history of these stairs by determining their geologic source. Built for Thomas Lee beginning in 1738, the hall was restored in 1929–1940. At that time the stairs of the south entrance were red sandstone. These early stairs were dismantled during the restoration and stored onsite. As part of the present study, we thin-sectioned the stored stones and compared them petrographically with samples of other red sandstones used around the Chesapeake Bay in the colonial period, including Seneca sandstone from Maryland and St. Bees sandstone from England. The Stratford stairs are made of lithic arkose, which resembles Seneca sandstone significantly more closely than St. Bees sandstone both in mineralogy and in grain size. If the Stratford stairs were made of Seneca sandstone, that would push their installation date forward to at least 1802, when the Patowmack Canal on the Virginia side of the Potomac River allowed transport of Seneca sandstone by boat, avoiding the falls on the river. A more likely even younger earliest date is 1832, as that is when the improved Chesapeake and Ohio Canal was functioning on the Maryland side. This has implications for decisions about the restoration of the mansion.
An alpine glacier below Sunlight Peak in northwest Wyoming was first photographically documented in 1893, near the end of the Little Ice Age and during the time of industrialization. Since then, evolving technologies have been applied to observe this glacier and nearby discontinuous permafrost for studies spanning Earth, environmental, and planetary sciences. Surveys in the 21st century indicate negative mass balance coinciding with rising average air temperature. This paper reviews the geological and geophysical data on record for the Sunlight Glacier system, presents new results from a 2023 fieldwork campaign combined with remote sensing analysis and comments on likely scenarios of future evolution for this individual body of ice within a broader alpine cryosphere feeding the watersheds of western North America.
In this paper, we review the basic concepts of topologically protected edge modes using the Su Schrieffer Heeger (SSH) model, originally introduced to describe electrical conductivity in doped polyacetylene polymer chains. We then propose an electrical circuit that emulates this model, provide its mathematical description, and present its experimental realization. The experimental setup is described in detail, with explanations designed to be broadly accessible without much prior familiarity with lattice theory, thus offering an introduction to this active area of research. Both theoretical predictions and experimental results confirm the presence of these modes, showing very good overall agreement. Using this concrete experimental system as a motivating example, we highlight the key aspects of topological protection.
This essay offers an ameliorative account of micromanagement from the perspective of those who experience it. It attempts to address hermeneutical injustice and unjustified threats to worker autonomy by coming to an understanding of the concept that serves the needs of its victims. Prevailing accounts analyze micromanagement from the perspective of the bottom line or the psychological state of the micromanager. By examining the phenomenon from the perspective of the micromanaged, we gain a better sense of the moral harms it presents. Because micromanagement raises deep questions about the nature of management and leadership, this project also affords an opportunity to revisit many perennial questions about leadership with a fresh lens.
