University of Massachusetts Amherst

Detailed understanding of aging biology and developing anti-aging therapeutic strategies are imperative but represent intrinsic challenges due to the lengthy nature of the aging process. Aging occurs naturally during repeated...

Qualitative research, rooted in interpretivism, is valuable for studying immigrant populations and understanding cultural influences on health behaviors. However, few studies have explored the methodological challenges of researching older Korean U.S. immigrants, particularly on sensitive topics like end-of-life care, which requires deep cultural understanding. This paper examines the challenges encountered during a pilot study on end-of-life care among older Korean U.S. immigrants. In addition to identifying key methodological obstacles, we highlight strategies to improve future research on sensitive topics within immigrant communities. Our study, informed by existing literature, faced unexpected challenges at every stage—recruitment, data collection, and analysis—each requiring careful adaptation. First, recruitment posed significant challenges. Many participants were hesitant to discuss end-of-life care due to cultural stigma, fearing it might invite misfortune. Some resisted signing consent forms, unfamiliar with Western research protocols and concerned about potential consequences. Others expected structured surveys rather than open-ended interviews, making engagement difficult. Second, conducting interviews brought additional hurdles. The setting needed to feel neutral, as medical or religious environments influenced responses. Language proficiency varied, requiring interpreters and adjusted phrasing. Discussions about end-of-life care sometimes triggered emotional distress, necessitating sensitivity and frequent check-ins. Third, data analysis required careful consideration. Translating nuanced Korean expressions into English was challenging, as some terms lacked direct equivalents. Case vignettes also needed thoughtful adaptation to ensure cultural relevance and avoid bias. Finally, participant feedback led to important revisions, reinforcing the value of involving participants throughout the research process. Engaging them early and reflecting on challenges afterward can improve study design and data quality. By addressing these methodological hurdles, this study provides practical insights for strengthening qualitative research on immigrant populations, particularly when exploring sensitive topics.

Museum specimens offer a unique and powerful tool for understanding the impact of anthropogenic change on populations over time. Morphological traits can be impacted by many different environmental variables that are difficult to separate from one another as potential driving factors. Comparative analyses among similar species jointly experiencing change in the same environmental variables can help pinpoint the selective pressures driving temporal morphological change. We assessed temporal change in bill size, tarsus length, and body size between six species of songbirds from the San Francisco Bay Area over the past 150 years. Wing length, as a proxy for body size, exhibited idiosyncratic temporal changes among species. In contrast, we found a significant increase in bill surface area across all but one species. Quantile regression analyses on bill size variation additionally revealed that temporal increases over the past century have been driven by increases in the largest bill sizes in some species, but increases in the smallest bills over time in others. The climate variables best explaining temporal change in bill size also differed among species, with some species responding more to changing summer variables (e.g. maximum annual temperature) and others in response to a changing winter climate. These results together suggest that different sympatric, resident bird species may be experiencing temporal morphological change in response to selective pressures experienced at different seasons. Our finding provides support for the season of critical thermal stress hypothesis that suggests variation in functional traits will be shaped by the season that imposes the greatest selective force on a population. Overall, this study has important implications for future research on the role of bills in thermoregulation and for conservation efforts based on the adaptive capacity of birds to respond to climate change.

Separating the effects of waves and turbulence in oceanographic time series is an ongoing challenge because surface wave motion and turbulence fluctuations can occur at overlapping frequencies. Therefore, simple bandpass filters cannot effectively separate their dynamics. While more advanced decomposition techniques have been developed, they often entail restrictive assumptions about the wave and turbulence interactions, require synchronized measurements, and/or only decompose the signal spectrally without a time series reconstruction. We present our new wave–turbulence decomposition technique which uses dynamic mode decomposition (DMD). The technique is signal agnostic so it can be applied to any time series, and our only assumptions are that the waves and turbulence can be separated and that the waves are the most coherent features in the signal. Our approach requires minimal tuning, where the main user input is the wave frequency range of interest. To demonstrate the method, we apply it to synthetic, field, and laboratory data and compare the results to other modal decomposition methods. A sensitivity analysis on the synthetic data shows that the most sensitive parameter to the accuracy is the rank truncation in the DMD, and that the decomposition performs the best when the wave energy in the signal is of equal or greater magnitude than that of the turbulence. Given the accuracy of our decomposition, we are able to analyze the velocity autocorrelation of the separated turbulence time series with minimal wave contamination. Overall, our decomposition method outperforms the other decomposition methods and provides for robust separation of the waves and turbulence, demonstrating wide applicability to ocean signal processing. Significance Statement When measuring physical, chemical, and biological quantities in the ocean, the measurements are often influenced by both waves and turbulence. Isolating the individual effects of waves and turbulence on those variables is important to a wide range of analyses, such as estimating how momentum, heat, and nutrients are mixed throughout the water column. In this work, we propose a new method to separate the wave and turbulence components in ocean-data time series. When tested on laboratory, field, and synthetic data, our method was able to separate the wave and turbulence components of a signal more effectively than previously proposed algorithms.

In this essay, we argue that, unlike previous changes in digital media technologies over the past few decades, this AI "turn" in journalism forces us to rethink journalism's identity and its relationship with audiences. While AI complicates and challenges some existing professional, social, political, and economic structures, it also offers new ways to realize desired journalistic objectives that were previously considered to be impractical, if not impossible. Drawing on four orienting ideas-adoption and hype, power and dependency, audiences and democratic implications, and education and empowerment-we unpack the implications of this AI turn in journalism and the consequences for the future of the journalistic field.

Losses are one of the main bottlenecks for the distribution of entanglement in quantum networks, which can be overcome by the implementation of quantum repeaters. The most basic form of a quantum repeater chain is the swap ASAP repeater chain. In such a repeater chain, elementary links are probabilistically generated and deterministically swapped as soon as two adjacent links have been generated. As each entangled state is waiting to be swapped, decoherence is experienced, turning the fidelity of the entangled state between the end nodes of the chain into a random variable. Fully characterizing the (average) fidelity as the repeater chain grows is still an open problem. Here, we analytically investigate the case of equally-spaced repeaters, where we find exact analytic formulae for all moments of the fidelity up to 25 segments. We obtain these formulae by providing a general solution in terms of a generating function ; a function whose n'th term in its Maclaurin series yields the moments of the fidelity for n segments. We generalize this approach as well to a global cut-off policy – a method for increasing fidelity at the cost of longer entanglement delivery times – allowing for fast optimization of the cut-off parameter by eliminating the need for Monte Carlo simulation. We furthermore find simple approximations of the average fidelity that are exponentially tight, and, for up to 10 segments, the full distribution of the delivered fidelity. We use this to analytically calculate the secret-key rate, both with and without binning methods.

This study is based on four focus group interviews with public school teachers in Massachusetts about reducing work hours as a means of improving their working conditions. Our analysis documents a common experience of overwork, expressed in the focus groups and measured by time-use diaries. Teachers reported long work hours and a significant ‘mental load’—both of which affect teachers’ quality of life, physical and mental health, relationships with their families and desire to keep teaching. While participants were union members and therefore experienced with collective bargaining, most approached the issue of overwork as an individual problem that must be solved by setting and maintaining personal boundaries. Focus group participants differed in their assessment of a hypothetical policy proposal for a work-time reduction without a loss of pay for teachers or instructional time for students. While generally supportive of the goal, participants questioned whether contractual reductions would correspond to actual reductions in hours worked. Teachers expressed both eagerness to include work-time reductions in future contracts, as well as scepticism that their districts had the fiscal space or political will to achieve this goal. Discussions revealed that teachers’ professional identities as hard-working and caring ‘perfectionists’ who are responsible for their students’ learning, inhibited their policy imaginations with regard to using collective bargaining to win them additional leisure time.

Turbulent emulsions are ubiquitous in chemical engineering, food processing, pharmaceuticals and other fields. However, our experimental understanding of this area remains limited due to the multiscale nature of turbulent flow and the presence of extensive interfaces, which pose significant challenges to optical measurements. In this study, we address these challenges by precisely matching the refractive indices of the continuous and dispersed phases, enabling us to measure local velocity information at high volume fractions. The emulsion is generated in a turbulent Taylor–Couette flow, with velocity measured at two radial locations: near the inner cylinder (boundary layer) and in the middle gap (bulk region). Near the inner cylinder, the presence of droplets suppresses the emission of angular velocity plumes, which reduces the mean azimuthal velocity and its root mean squared fluctuation. The former effect leads to a higher angular velocity gradient in the boundary layer, resulting in greater global drag on the system. In the bulk region, although droplets suppress turbulence fluctuations, they enhance the cross-correlation between azimuthal and radial velocities, leaving the angular velocity flux contributed by the turbulent flow nearly unchanged. In both locations, droplets suppress turbulence at scales larger than the average droplet diameter and increase the intermittency of velocity increments. However, the effects of the droplets are more pronounced near the inner cylinder than in the bulk, likely because droplets fragment in the boundary layer but are less prone to break up in the bulk. Our study provides experimental insights into how dispersed droplets modulate global drag, coherent structures and the multiscale characteristics of turbulent flow.

Enterotoxigenic Escherichia ( E. ) coli (ETEC) and enteropathogenic E. coli (EPEC) are major bacterial causes of childhood diarrhea. We explored the clinico-epidemiological characteristics of children aged <5 years associated with moderate-to-severe diarrhea (MSD), asymptomatic ETEC or EPEC infections, and subsequent impact on growth reflected by z-score. Data from 9,439 MSD and 13,128 asymptomatic children were extracted from Global Enteric Multicenter Study, conducted between 2007 and 2011. Epidemiological risk factors and clinical characteristics of ETEC and EPEC infection were explored using multivariable logistic regression, and a paired t -test was used to investigate the impact of infection on nutritional status. Children aged 12–23 months were more affected by ETEC-positive MSD compared with 0–11 months, whereas children aged 0–11 months were more vulnerable to EPEC-positive MSD. ETEC- and EPEC-positive MSD children showed more characteristics of clinical dehydration like sunken eyes and loss of skin turgor preservation, and needed more intravenous rehydration than ETEC- and EPEC-negative MSD children. Among the other identified co-pathogen, presence of Campylobacter in the analyzed stool sample had higher likelihood to be associated with symptomatic MSD (adjusted odds ratio [aOR] 1.42, 95% CI 1.17–1.71) and asymptomatic children with ETEC infection (aOR 1.42, 95% CI 1.16–1.73) and asymptomatic EPEC infection (aOR 1.22, 95% CI 1.04–1.43). Significant growth faltering was noted in MSD children with ETEC (mean difference 0.22, 95% CI 0.10–0.34) and EPEC (mean difference 0.15, 95% CI 0.03–0.27) from baseline to ∼60 days (50–90 days). Our findings highlight the need to implement preventative strategies to reduce the risk of diarrheal illnesses.

Intensely contracting fast skeletal muscle rapidly loses the ability to generate force, due in part to the accumulation of phosphate (P i ) inhibiting myosin’s force-generating capacity, in a process that is strain dependent. Crucial aspects of the mechanism underlying this inhibition remain unclear. Therefore, we directly determined the effects of increasing [P i ] on rabbit psoas muscle myosin’s ability to generate force against progressively higher resistive loads in a laser trap assay, with the requisite spatial and temporal resolution to discern the mechanism of inhibition. Myosin’s force-generating capacity decreased with increasing [P i ], an effect that became more pronounced at higher resistive loads. The decrease in force resulted from myosin’s accelerated detachment from actin, which also increased at higher resistive forces. These data are well fit by a cross-bridge model in which P i rebinds to actomyosin in a postpowerstroke, ADP-bound state before accelerating myosin’s detachment from actin. Thus, these findings provide important molecular insight into the mechanism underlying the P i -induced loss of force during muscle fatigue from intense contractile activity.

There has not been comprehensive national data collection of wastewater infrastructure serving the US population for 30 years, creating a data gap with implications for public health and asset management. We developed a model leveraging geospatial data and machine learning (Random Forest) to predict wastewater infrastructure in places where it is unknown. We employ a two-stage machine learning approach to model wastewater infrastructure coverage: Stage 1 identifies whether a parcel needs wastewater infrastructure and Stage 2 identifies whether it is served by an onsite wastewater treatment system or by a centralized sewer connection. We test this approach using data from Florida, including evaluating the approach’s applicability within Florida and an out-of-sample test in Virginia. The model achieved 91.8% accuracy across Florida with a 96.4% median Stage 2 confidence, suggesting potential use of confidence as a proxy for accuracy where ground-truth data is limited. The model achieved 81.9% accuracy in Virginia when predicting with a model trained only on data from Florida, suggesting strong transferability to new geographies. Variations in performance highlight opportunities for improvement in resolving sewer service boundary underestimation and testing to account for a range of local and historical circumstances. Our approach represents a scalable and transferable framework.

A bstract We present a complete proof of the Weak Gravity Conjecture in any perturbative bosonic string theory in spacetime dimension D ≥ 6. Our proof works by relating the black hole extremality bound to long range forces, which are more easily calculated on the worldsheet, closing the gaps in partial arguments in the existing literature. We simultaneously establish a strict, sublattice form of the conjecture in the same class of theories. We close by discussing the scope and limitations of our analysis, along with possible extensions including an upcoming generalization of our work to the superstring.

Despite making up 5-20 wt.% of Earth’s predominantly iron core, the melting properties of elemental nickel at core conditions remain poorly understood, due largely to a dearth of experimental data. We present here an in situ X-ray diffraction study performed on laser shock-compressed samples of bulk nickel, reaching pressures up to ~ 500 GPa. Hugoniot states of nickel were targeted using a flat-top laser drive, with in situ X-ray diffraction data collected using the Linac Coherent Light Source. Rietveld methods were used to determine the densities of the shocked states from the measured diffraction data, while peak pressures were determined using a combination of measured particle velocities, shock transit times, hydrodynamic simulations, and laser intensity calibrations. We observed solid compressed face-centered cubic (fcc) Ni up to at least 332 ± 30 GPa along the Hugoniot—significantly higher than expected from the majority of melt lines that have been proposed for nickel. We also bracket the partial melting onset to between 377 ± 38 GPa and 486 ± 35 GPa.

Trypanosoma brucei is a tractable protist parasite for which many genetic tools have been developed to study novel biology. A striking feature of T. brucei is the catenated mitochondrial DNA network called the kinetoplast DNA (kDNA) that is essential for parasite survival and life cycle completion. Maintenance of kDNA requires three independently essential paralogs that have homology to bacterial DNA polymerase I (POLIB, POLIC and POLID). We previously demonstrated that POLIB has a divergent domain architecture that displayed enzymatic properties atypical for replicative DNA polymerases. To evaluate the functional domains required for kDNA replication in vivo, we pursued an RNAi complementation approach based on the widely used tetracycline (Tet) single inducer system. Tet induction of RNAi and complementation with wildtype POLIB (POLIBWT) resulted in a 93% knockdown of endogenous POLIB mRNA but insufficient ectopic POLIBWT expression. This incomplete rescue emphasized the need for a more versatile induction system that will allow independent, tunable, and temporal regulation of gene expression. Hence, we adapted a dual control vanillic acid (Van)-Tet system that can independently control gene expression for robust RNAi complementation. Dual induction with Van and Tet (RNAi + Overexpression) resulted in 91% endogenous POLIB knockdown accompanied by robust and sustained ectopic expression of POLIBWT, and a near complete rescue of the POLIB RNAi defects. To more precisely quantify changes in kDNA size during RNAi, we also developed a semi-automated 3D image analysis tool to measure kDNA volume. Here we provide proof of principle for a dual inducer system that allows more flexible control of gene expression to perform RNAi and overexpression independently or concurrently within a single cell line. This system overcomes limitations of the single inducer system and can be valuable for elegant mechanistic studies in the field.

Mycobacterial cell envelopes are rich in unusual lipids and glycans that play key roles during infection and vaccination. The most abundant envelope glycolipid is trehalose dimycolate (TDM). TDM compromises the host response to mycobacterial species via multiple mechanisms, including inhibition of phagosome maturation. The molecular mechanism by which TDM inhibits phagosome maturation has been elusive. We find that a clickable, photoaffinity TDM probe recapitulates key phenotypes of native TDM in macrophage host cells and binds several host Soluble N-ethylmaleimide-Sensitive Factor Attachment Proteins Receptor (SNARE) proteins, including Vesicle Transport through Interaction with t-SNAREs 1B (VTI1B), Syntaxin 8 (STX8), and Vesicle-Associated Membrane Protein 2 (VAMP2). VTI1B and STX8 normally promote endosome fusion by forming a complex with VAMP8. However, in the presence of Mycobacterium tuberculosis , VTI1B and STX8 complex with VAMP2, which in turn decreases VAMP8 binding. VAMP2 acts together with mycolate structure to inhibit phagosome maturation and promotes intracellular M. tuberculosis replication. Thus one mechanism by which TDM constrains the innate immune response to M. tuberculosis is via noncanonical SNARE complexation.

Production of maple syrup from sugar maples (Acer saccharum) in suburban areas lies at the intersection of urban farming and forestry, providing an artisanal food as well as ecosystem services. However, urban areas can be enriched with trace elements due to industrial, agricultural, and municipal pollution, which can potentially affect sap and syrup chemistry. Here, we collected soils, sap, and maple syrup from four artisanal maple syrup producers in four suburban areas across the northeastern United States to assess nutrient and trace element concentrations. Soil As and Pb concentration approached or exceeded EPA limits while Cd, Cu, and Zn were far below EPA limits. Sap and syrup As, Cd, Ni, Pb, and Zn concentrations reached or exceeded FDA limits for food. However, Total Hazard Quotients suggest that urban maple syrup consumption poses low to no health risk to adults and children.