Multi-wavelength observations of low-mass X-ray binaries (LMXBs) during bright outbursts reveal many details about the coupling of their inflows and outflows. However, only high angular resolution radio observations are able to resolve and track the motion and variability of individual jet ejecta. We present the results of our intensive VLBI campaign on the black-hole low-mass X-ray binary (LMXB) Swift J1727.8-1613 during its 2023–2024 outburst. We observed the repeated quenching and re-establishment of the highly-extended continuous core jet during several transitions between hard-intermediate and soft-intermediate states, and the repeated ejection of transient jets. Using time-dependent visibility model fitting, we tracked the motion of nine discrete jet knots, obtaining some of the most precise measurements of transient jet proper motions and ejection dates in an LMXB. These ejecta were only detectable for a short time with VLBI, and some showed rapid intra-observation flux density variability that was not captured in image reconstructions. For the first time, we use time-dependent visibility modelling to fit a piecewise model for the jet knot flux densities, allowing us to create complex, non-parametric light curves of their intra-observation variability. We observed the launching of multiple ejecta across several state transitions; however, we could not identify a consistent signature of jet ejection in the available X-ray intensity or hardness data. We constrained the intrinsic speeds and bulk Lorentz factors of the jet knots, finding that Swift J1727.8-1613 launched both mildly relativistic ($\beta\Gamma\lt$1) and highly relativistic ($\beta\Gamma\gt$2) ejecta throughout its outburst. We used their proper motions to constrain a posterior distribution for the maximum inclination angle of the jet axis, which had 50th, 84th, and 99th percentiles of $40^\circ$, $50^\circ$, and $66^\circ$, respectively. These unique observations of the repeated ejection of transient jets by a single LMXB reveal that fixed parameters such as black-hole mass, black-hole spin, and spin–orbit misalignment do not uniquely determine the varying properties of transient jets, particularly their speeds and Lorentz factors.

This article prefaces our Special Issue on “AI and the Decision to Go to War.” We begin by introducing the prospect of artificial intelligence (AI)-enabled systems increasingly infiltrating state-level decision making on the resort to force, clarifying that our focus is on existing technologies, and outlining the two general ways that this can conceivably occur: through automated self-defense and AI-enabled decision-support systems. We then highlight recent, on-going developments that create a backdrop of rapid change and global uncertainty against which AI-enabled systems will inform such deliberations: (i) the widespread tendency to misperceive the latest AI-enabled technologies as increasingly “human”; (ii) the changing role of “Big Tech” in the global competition over military applications of AI; (iii) a conspicuous blind spot in current discussions surrounding international regulation; and (iv) the emerging reality of an AI-nuclear weapons nexus. We suggest that each factor will affect the trajectory of AI-informed war initiation and must be addressed as scholars and policymakers determine how best to prepare for, direct, and respond to this anticipated change. Finally, turning to the pressing legal, ethical, sociotechnical, political, and geopolitical challenges that will accompany this transformation, we revisit four “complications” that have framed the broader project from which this Special Issue has emerged. Within this framework, we preview the other 13 multidisciplinary research articles that make up this collection. Together, these articles explore the risks and opportunities that will follow AI into the war-room.

This study considers key value differences between leaders of two types of social ventures: for-profit social benefit corporations and nonprofit organizations. The research question asks to what degree the value sets of leaders of benefit corporations are congruent with those of similarly situated individuals in nonprofit organizations. The results show the values of leaders working in benefit corporations and nonprofit organizations are in many ways aligned, but there are notable statistical differences. A sectoral association of values is also present with employees in both types of organization, especially when the previous work experience of employees is considered.

The diffusion of exchanged Yb, Ho, and Eu from interlayer positions in montmorillonite was studied using infrared spectroscopy (IR), X-ray powder diffraction, and cation-exchange measurements. Dehydration of exchanged montmorillonite between 100° and 280°C caused the ions to diffuse into the hexagonal rings of surface oxygens. Subsequent migration into vacant octahedral sites was small regardless of the radius of the cation. Considerable ion fixation in excess of the cation-exchange capacity of the clay was observed at 20°C in both water and a 1:1 water:95% ethanol mixture. Evidence for hydrolysis as a possible mechanism for cation fixation was obtained by observing frequency shifts for deuterated hydroxyl groups using IR spectroscopy. A major IR band centered at 2680 cm−1 was observed for all three lanthanide-exchanged montmorillonites studied and assigned to the OH-stretching frequency of a lanthanide hydroxide. This band intensified on heating at 300°C for 1 hr. An IR band between 690 and 710 cm−1 also was observed for all three lanthanide-exchanged montmorillonites and was assigned to a lanthanide-hydroxyl deformation mode. No hydrolysis was observed for Na-montmorillonite, as expected from the very low hydration energy of Na+.

X-ray diffraction, infrared, and cation-exchange capacity measurements of the reaction products of montmorillonites with YbCl3.6H2O show that at 1 atm irreversible sorption of Yb3+ increases with increasing temperature in the range 20° to 280°C, whereas at 110 atm it decreases with increasing temperature. Above 100°C, less irreversible sorption occurs at 110 atm than at 1 atm. The decreased sorption at high pressure is attributed to reduced cation hydrolytic fixation and to rapid expulsion of interlayer Yb3+ by interlayer water at higher temperatures, with a concomitant decrease in Yb3+ migration to octahedral sites. At 110 atm, 160° and 200°C treatments cause changes in infrared absorption bands (884 cm-1, 848 cm-1) suggesting that sorbed Yb3+ is charge compensated by the deprotonation of Fe3+- and Mg2+-hydroxyl groups. At 290°C deprotonation is restricted to Fe3+-hydroxyl groups.

A crucial reckoning was initiated when the COVID-19 pandemic began to expose and intensify long-standing racial/ethnic health inequities, all while various sectors of society pursued racial justice reform. As a result, there has been a contextual shift towards broader recognition of systemic racism, and not race, as the shared foundational driver of both societal maladies. This confluence of issues is of particular relevance to Black populations disproportionately affected by the pandemic and racial injustice. In response, institutions have initiated diversity, equity, and inclusion (DEI) efforts as a way forward. This article considers how the dual pandemic climate of COVID-19-related health inequities and the racial justice movement could exacerbate the “time and effort tax” on Black faculty to engage in DEI efforts in academia and biomedicine. We discuss the impact of this “tax” on career advancement and well-being, and introduce an operational framework for considering the interconnected influence of systemic racism, the dual pandemics, and DEI work on the experience of Black faculty. If not meaningfully addressed, the “time and effort tax” could contribute to Black and other underrepresented minority faculty leaving academia and biomedicine – consequently, the very diversity, equity, and inclusion work meant to increase representation could decrease it.

Distinguished Oral

Background: Shared Healthcare Intervention to Eliminate Life-threatening Dissemination of MDROs in Orange County, California (SHIELD OC) was a CDC-funded regional decolonization intervention from April 2017 through July 2019 involving 38 hospitals, nursing homes (NHs), and long-term acute-care hospitals (LTACHs) to reduce MDROs. Decolonization in NH and LTACHs consisted of universal antiseptic bathing with chlorhexidine (CHG) for routine bathing and showering plus nasal iodophor decolonization (Monday through Friday, twice daily every other week). Hospitals used universal CHG in ICUs and provided daily CHG and nasal iodophor to patients in contact precautions. We sought to evaluate whether decolonization reduced hospitalization and associated healthcare costs due to infections among residents of NHs participating in SHIELD compared to nonparticipating NHs. Methods: Medicaid insurer data covering NH residents in Orange County were used to calculate hospitalization rates due to a primary diagnosis of infection (counts per member quarter), hospital bed days/member-quarter, and expenditures/member quarter from the fourth quarter of 2015 to the second quarter of 2019. We used a time-series design and a segmented regression analysis to evaluate changes attributable to the SHIELD OC intervention among participating and nonparticipating NHs. Results: Across the SHIELD OC intervention period, intervention NHs experienced a 44% decrease in hospitalization rates, a 43% decrease in hospital bed days, and a 53% decrease in Medicaid expenditures when comparing the last quarter of the intervention to the baseline period (Fig. 1). These data translated to a significant downward slope, with a reduction of 4% per quarter in hospital admissions due to infection (P < .001), a reduction of 7% per quarter in hospitalization days due to infection (P < .001), and a reduction of 9% per quarter in Medicaid expenditures (P = .019) per NH resident. Conclusions: The universal CHG bathing and nasal decolonization intervention adopted by NHs in the SHIELD OC collaborative resulted in large, meaningful reductions in hospitalization events, hospitalization days, and healthcare expenditures among Medicaid-insured NH residents. The findings led CalOptima, the Medicaid provider in Orange County, California, to launch an NH incentive program that provides dedicated training and covers the cost of CHG and nasal iodophor for OC NHs that enroll.

Funding: None

Disclosures: Gabrielle M. Gussin, University of California, Irvine, Stryker (Sage Products): Conducting studies in which contributed antiseptic product is provided to participating hospitals and nursing homes. Clorox: Conducting studies in which contributed antiseptic product is provided to participating hospitals and nursing homes. Medline: Conducting studies in which contributed antiseptic product is provided to participating hospitals and nursing homes. Xttrium: Conducting studies in which contributed antiseptic product is provided to participating hospitals and nursing homes.

Introduction: Abdominal pain is one of the most frequent reasons for an emergency department (ED) visit. Most cases are functional and no therapy has proven effective. Our objective was to determine if hyoscine butylbromide (HBB) (BuscopanTM) is effective for children who present to the ED with functional abdominal pain. Methods: We conducted a randomized, blinded, superiority trial comparing HBB 10 mg plus acetaminophen placebo to oral acetaminophen 15 mg/kg (max 975 mg) plus HBB placebo using a double-dummy approach. We included children 8-17 years presenting to the ED at London Health Sciences Centre with colicky abdominal pain rated >40 mm on a 100 mm visual analog scale (VAS). The primary outcome was VAS pain score at 80 minutes post-administration. Secondary outcomes included adverse effects; caregiver satisfaction with pain management using a five-item Likert scale; recidivism and missed surgical diagnoses within 24-hours of discharge. Analysis was based on intention to treat. Results: We analyzed 225 participants (112 acetaminophen; 113 HBB). The mean (SD) age was 12.4 (3.0) years and 148/225 (65.8%) were females. Prior to enrollment, the median (IQR) duration of pain prior was 2 (4.5) hours and analgesia was provided to 101/225 (44.9%) of participants. The mean (SD) pre-intervention pain scores in the acetaminophen and HBB groups were 62.7 (15.9) mm and 60.3 (17.3) mm, respectively. At 80 minutes, the mean (SD) pain scores in the acetaminophen and HBB groups were 30.1 (28.8) mm and 29.4 (26.4) mm, respectively and there were no significant differences adjusting for pre-intervention scores (p = 0.96). The median (IQR) caregiver satisfaction was high in the acetaminophen [5 (2)] and HBB [5 (1)] groups (p = 0.79). The median (IQR) length of stay between acetaminophen [235 (101)] and HBB [234 (103)] was not significantly different (p = 0.53). The proportion of participants with a return visit for abdominal pain was 4/112 (3.5%) in the acetaminophen group and 6/113 (5.3%) in the HBB group. The most common adverse effect was nausea (9% in each group) and there were no significant differences in adverse effects between acetaminophen (26/112, 23.2%) and HBB (31/113, 27.4%) (p = 0.52). There were no missed surgical diagnoses. Conclusion: For children with presumed functional abdominal pain who present to the ED, both acetaminophen and HBB produce a clinically important (VAS < 30 mm) reduction in pain and should be routinely considered in this clinical setting.

Crop yield loss–weed density relationships critically influence calculation of economic thresholds and the resulting management recommendations made by a bioeconomic model. To examine site-to-site and year-to-year variation in winter Triticum aestivum L. (winter wheat)–Aegilops cylindrica Host. (jointed goatgrass) interference relationships, the rectangular hyperbolic yield loss function was fit to data sets from multiyear field experiments conducted at Colorado, Idaho, Kansas, Montana, Nebraska, Utah, Washington, and Wyoming. The model was fit to three measures of A. cylindrica density: fall seedling, spring seedling, and reproductive tiller densities. Two parameters: i, the slope of the yield loss curve as A. cylindrica density approaches zero, and a, the maximum percentage yield loss as A. cylindrica density becomes very large, were estimated for each data set using nonlinear regression. Fit of the model to the data was better using spring seedling densities than fall seedling densities, but it was similar for spring seedling and reproductive tiller densities based on the residual mean square (RMS) values. Yield loss functions were less variable among years within a site than among sites for all measures of weed density. For the one site where year-to-year variation was observed (Archer, WY), parameter a varied significantly among years, but parameter i did not. Yield loss functions differed significantly among sites for 7 of 10 comparisons. Site-to-site statistical differences were generally due to variation in estimates of parameter i. Site-to-site and year-to-year variation in winter T. aestivum–A. cylindrica yield loss parameter estimates indicated that management recommendations made by a bioeconomic model cannot be based on a single yield loss function with the same parameter values for the winter T. aestivum-producing region. The predictive ability of a bioeconomic model is likely to be improved when yield loss functions incorporating time of emergence and crop density are built into the model's structure.

Three models that empirically predict crop yield from crop and weed density were evaluated for their fit to 30 data sets from multistate, multiyear winter wheat–jointed goatgrass interference experiments. The purpose of the evaluation was to identify which model would generally perform best for the prediction of yield (damage function) in a bioeconomic model and which model would best fulfill criteria for hypothesis testing with limited amounts of data. Seven criteria were used to assess the fit of the models to the data. Overall, Model 2 provided the best statistical description of the data. Model 2 regressions were most often statistically significant, as indicated by approximate F tests, explained the largest proportion of total variation about the mean, gave the smallest residual sum of squares, and returned residuals with random distribution more often than Models 1 and 3. Model 2 performed less well based on the remaining criteria. Model 3 outperformed Models 1 and 2 in the number of parameters estimated that were statistically significant. Model 1 outperformed Models 2 and 3 in the proportion of regressions that converged on a solution and more readily exhibited an asymptotic relationship between winter wheat yield and both winter wheat and jointed goatgrass density under the constraint of limited data. In contrast, Model 2 exhibited a relatively linear relationship between yield and crop density and little effect of increasing jointed goatgrass density on yield, thus overpredicting yield at high weed densities when data were scarce. Model 2 had statistical properties that made it superior for hypothesis testing; however, Model 1's properties were determined superior for the damage function in the winter wheat–jointed goatgrass bioeconomic model because it was less likely to cause bias in yield predictions based on data sets of minimum size.

We examined two potentially interacting, connected pathways by which parental supportiveness during early adolescence (ages 1–13) may come to be associated with later African American young adult smoking. The first pathway is between parental supportiveness and young adult stress (age 19), with stress, in turn, predicting increased smoking at age 20. The second pathway is between supportive parenting and tumor necrosis factor (TNF) gene methylation (i.e., TNFm), a proinflammatory epitype, with low levels indicating greater inflammatory potential and forecasting increased risk for smoking in response to young adult stress. In a sample of 382 African American youth residing in rural Georgia, followed from early adolescence (age 10–11) to young adulthood (age 20), supportive parenting indirectly predicted smoking via associations with young adult stress, IE = –0.071, 95% confidence interval [–0.132, –0.010]. In addition, supportive parenting was associated with TNFm measured at age 20 (r = .177, p = .001). Further, lower TNFm was associated with a significantly steeper slope (b = 0.583, p = .003) of increased smoking in response to young adult stress compared to those with higher TNFm (b = 0.155, p = .291), indicating an indirect, amplifying role for supportive parenting via TNFm. The results suggest that supportive parenting in early adolescence may play a role in understanding the emergence of smoking in young adulthood.

Knowledge of the lead-lag relationships among the retail, wholesale, and farm level prices of a livestock commodity is of obvious importance both in econometric model building and in evaluation of packers' and retailers' margins for that commodity. Though the lead-lag relationships for beef prices have been investigated in several previous studies (Barksdale et al.; Franzmann and Walker; King; Miller; National Commission on Food Marketing), the only known previous study of the lead-lag relationships for pork is that made by the National Commission on Food Marketing (hereafter abbreviated NCFM). As that study used data for 1962-1965, changes in the pork marketing system in subsequent years may have in turn occassioned changes in the lead-lag relationships. The changes in the pork marketing system include changes in market structure at the farm, packer, and retail levels, increased use of formula pricing, and the demise of terminal markets, among others. Also, as discussed hereafter, the statistical method used in the NCFM analysis of lead-lag relationships involved certain problems which may invalidate the conclusions drawn in that study.