A study published in the Journal of Statistical Mechanics: Theory and Experiment (JSTAT), inspired by the behavior of bacterial colonies observed in previous experiments, uses mathematical models to describe the expansion of competing populations. The aim is to understand which factors determine the success of one population over another. According to the study, fitness — understood here as a reproductive advantage — is not the only factor involved, nor is it necessarily the decisive one: expansion speed and position along the growth front also matter. The shapes of the expanding front predicted by the model closely resemble those observed in earlier experiments of microbial colonies. The study also makes a new prediction: that spatial structure leaves a measurable fingerprint on how fitness is distributed across a population, which new experiments could look for. 

About the Study: What is the potential impact of expanding alcohol screening and brief interventions in primary care on premature mortality from major alcohol-related causes of death in US adults? In this decision analytical model and microsimulation study, expanding delivery of alcohol brief interventions to an additional 8 million interventions per year was projected to reduce annual alcohol-related potential years of life lost per 100 000 adults by −51.3 (95% credible interval [CrI], −73.2 to −32.8) in men and −34.1 (CrI, −54.5 to −16.1) in women by 2030 compared with the status quo. These findings suggest that substantially expanding alcohol screening and brief interventions in primary care may reduce premature mortality and help narrow the socioeconomic gap in alcohol-related mortality in the US.

About the Study: What are the long-term trends in US nursing home closures and ownership transitions and how are facility characteristics associated with different types of operational change? In this cohort study of 33 110 US nursing home locations from 1985 to 2025, nearly half of the facilities followed simple entry-exit patterns, while approximately one-fifth remained operational despite ownership changes. Organizational restructuring, including change of ownership and within-facility capacity reconfiguration, became more common over time and was more prevalent than permanent facility closure or market exit. These findings suggest that nursing home closures often reflect broader organizational restructuring rather than true market exit, highlighting the importance of incorporating ownership transitions and capacity changes into nursing home policy and oversight.

About the Study: Among adults with HIV at risk of treatment-associated weight gain, does an alternative first-line regimen produce less weight gain than treatment combinations containing an integrase strand transfer inhibitor (eg, dolutegravir or bictegravir) along with tenofovir alafenamide? In this noninferiority randomized clinical trial including 600 adults with HIV, initiating a regimen with doravirine, lamivudine, and tenofovir disoproxil fumarate was noninferior to a regimen with dolutegravir, emtricitabine, and tenofovir alafenamide for viral suppression (HIV RNA level <50 copies/mL) at 48 weeks (89.0% vs 90.7%, respectively, meeting the prespecified noninferiority margin of −10 percentage points), and was associated with less weight gain. Among adults initiating antiretroviral therapy, a regimen with doravirine, lamivudine, and tenofovir disoproxil fumarate was noninferior to a regimen with dolutegravir, emtricitabine, and tenofovir alafenamide for viral suppression at 48 weeks and was associated with less weight gain.

Mathematicians have shown that completely fair elections are – in a sense – impossible. No electoral system can guarantee both that local votes translate directly into local seats, and that total seat distribution matches overall vote shares: not without an indefinitely growing parliament.

About the Study: Is combined inhibition of programmed cell death 1 protein (PD-1) and lymphocyte activation gene 3 (LAG-3) added to standard neoadjuvant chemotherapy (NAC) safe and effective in (formerly HER2)-negative early-stage breast cancer at high risk of recurrence? This phase 2 randomized clinical trial including 78 participants with -negative breast cancer found that combining cemiplimab and fianlimab with paclitaxel-based NAC improved rates of pathologic complete response in all participants, including those with triple-negative and hormone receptor−positive subtypes. Patients positive for the ImPrint immune signature were highly sensitive to the combination, providing a potential biomarker of treatment response. These results indicate that combined PD-1 and LAG-3 inhibition warrants further investigation in -negative breast cancer.