Macalester College
  • Saint Paul, United States
Recent publications
Background There are documented racial/ethnic and sex differences in pediatric cancer survival; however, it is unknown whether pediatric cancer survival disparities exist when race/ethnicity and sex are considered jointly. Methods Using SEER data (2000–2017), we estimated survival differences by race/ethnicity within sexes and by sex within race/ethnicity (White, Black, Hispanic, and Asian/Pacific Islander [API]) for 17 cancers in children aged (0–19 years). Kaplan-Meier curves (Log-Rank p-values) were assessed. Cox regression was used to estimate hazards ratios (HRs) and 95 % confidence intervals (95 % CIs) between race/ethnicity/sex and cancer. Results We included 51,759 cases (53.6 % male, 51.9 % White). There were statistically significant differences in 18-year survival by race/ethnicity-sex for 12/17 cancers. Within sexes, minorities had an increased risk of death compared to Whites for various cancers including acute lymphoblastic leukemia (ALL) (females: HispanicHR: 1.78, 95 % CI: 1.52, 2.10; BlackHR: 1.70, 95 % CI: 1.29, 2.24; APIHR: 1.42, 95 % CI: 1.07–1.89; males ALL: HispanicHR: 1.58, 95 % CI: 1.39,1.79; BlackHR: 1.57, 95 % CI: 1.26,1,95; API-HR: 1.39, 95 % CI: 1.11, 1.75) and astrocytoma (females: HispanicHR: 1.49, 95 % CI: 1.19, 1.85; BlackHR: 1.67, 95 % CI: 1.29, 2.17; API-HR: 1.51, 95 % CI: 1.05, 2.15; males: HispanicHR:1.27, 95 % CI: 1.04, 1.56; BlackHR: 1.69, 95 % CI: 1.32, 2.17; API-HR: 1.92, 95 % CI: 1.43, 2.58). Sex differences in survival within racial/ethnic groups were observed for White (ALL, osteosarcoma), Hispanic (medulloblastoma), and API (Primitive Neuro-Ectodermal Tumor [PNET]) children. Conclusions There are disparities in survival by both race/ethnicity and sex highlighting the societal and biologic influences these features have on survival in children with cancer.
Objective: To evaluate the effect of mask wearing on facial attractiveness and projected first impressions during the COVID-19 pandemic. Methods: A total of 8 models were evaluated by 200 live raters and 750 online raters both with and without masks while smiling maximally. Both live and online raters looked at the models for fifteen seconds, then completed a first impressions questionnaire. Results: Overall ratings for attractiveness were higher for both masked and unmasked conditions in-person versus online. Males were perceived more favorably both in impressions and attractiveness online when masked, whereas in person they were more favorable when unmasked. Females were perceived more favorably in impressions when unmasked both online and in person, but their attractiveness rating was higher when masked both online and in person. Regardless of gender and masking state, all first impressions were more favorable in person versus online. The differences were statistically significant (all p<0.05). Conclusions: Face masks have different effects for males versus females in both an online and in-person setting. Men are perceived more positively in-person when they smile unmasked while they are better ranked online when they smile masked. Females are better perceived in all domains other than attractiveness when smiling unmasked both online and in person. To optimize first impressions, individuals should seek to meet In person whenever possible when forming new relationships.
The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America’s Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the ‘zenith of dinosaur diversity’. The wide latitudinal distribution of rocks and fossils that represent this episode, spanning from northern Mexico to the northern slopes of Alaska, provides a unique opportunity to gain insights into dinosaur paleoecology and to address outstanding questions regarding faunal provinciality in connection to paleogeography and climate. Whereas reliable basin-wide correlations are fundamental to investigations of this sort, three decades of radioisotope geochronology of various vintages and limited compatibility has complicated correlation of distant fossil-bearing successions and given rise to contradictory paleobiogeographic and evolutionary hypotheses. Here we present new U–Pb geochronology by the CA-ID-TIMS method for 16 stratigraphically well constrained bentonite beds, ranging in age from 82.419 ± 0.074 Ma to 73.496 ± 0.039 Ma (2σ internal uncertainties), and the resulting Bayesian age models for six key fossil-bearing formations over a 1600 km latitudinal distance from northwest New Mexico, USA to southern Alberta, Canada. Our high-resolution chronostratigraphic framework for the upper Campanian of the Western Interior Basin reveals that despite their contrasting depositional settings and basin evolution histories, significant age overlap exists between the main fossil-bearing intervals of the Kaiparowits Formation (southern Utah), Judith River Formation (central Montana), Two Medicine Formation (western Montana) and Dinosaur Park Formation (southern Alberta). Pending more extensive paleontologic collecting that would allow more rigorous faunal analyses, our results support a first-order connection between paleoecologic and fossil diversities and help overcome the chronostratigraphic ambiguities that have impeded the testing of proposed models of latitudinal provinciality of dinosaur taxa during the Campanian.
Submarine groundwater discharge is increasingly recognized as an important component of the oceanic geochemical budget, but knowledge of the distribution of this phenomenon is limited. To date, reports of meteoric inputs to marine sediments are typically limited to shallow shelf and coastal environments, whereas contributions of freshwater along deeper sections of tectonically active margins have generally been attributed to silicate diagenesis, mineral dehydration, or methane hydrate dissociation. Here, using geochemical fingerprinting of pore water data from Site J1003 recovered from the Chilean Margin during D/V JOIDES Resolution Expedition 379 T, we show that substantial offshore freshening reflects deep and focused contributions of meteorically modified geothermal groundwater, which is likely sourced from a reservoir ~2.8 km deep in the Aysén region of Patagonia and infiltrated marine sediments during or shortly after the last glacial period. Emplacement of fossil groundwaters reflects an apparently ubiquitous phenomenon in margin sediments globally, but our results now identify an unappreciated locus of deep submarine groundwater discharge along active margins with potential implications for coastal biogeochemical processes and tectonic instability.
Background: Black children have lower incidence yet worse survival than White and Latinx children with B-cell acute lymphoblastic leukemia (B-ALL). It is unclear how reported race/ethnicity (RRE) is associated with death in B-ALL after accounting for differentially expressed genes associated with genetic ancestry. Methods: Using Phase 1 and 2 NCI TARGET B-ALL cases (N = 273; RRE-Black = 21, RRE-White = 162, RRE-Latinx = 69, RRE-Other = 9, RRE-Unknown = 12), we estimated proportions of African (AFR), European (EUR), and Amerindian (AMR) genetic ancestry. We estimated hazard ratios (HR) and 95% confidence intervals (95% CI) between ancestry and death while adjusting for RRE and clinical measures. We identified genes associated with genetic ancestry and adjusted for them in RRE and death associations. Results: Genetic ancestry varied within RRE (RRE-Black, AFR proportion: Mean: 78.5%, Range: 38.2%-93.6%; RRE-White, EUR proportion: Mean: 94%, Range: 1.6%-99.9%; RRE-Latinx, AMR proportion: Mean: 52.0%, Range: 1.2%-98.7%). We identified 10, 1, and 6 differentially expressed genes (padjusted <0.05) associated with AFR, AMR, and EUR ancestry proportion, respectively. We found AMR and AFR ancestry were statistically significantly associated with death (AMR each 10% HR: 1.05, 95% CI: 1.03-1.17, AFR each 10% increase HR: 1.03, 95% CI:1.01-1.19). RRE differences in the risk of death were larger in magnitude upon adjustment for genes associated with genetic ancestry for RRE-Black, but not RRE-Latinx children (RRE-Black HR: 3.35, 95% CI: 1.31, 8.53; RRE-Latinx HR: 1.47, 0.88-2.45). Conclusions: Our work highlights B-ALL survival differences by RRE after adjusting for ancestry differentially expressed genes suggesting other factors impacting survival are important.
Perand polyfluoroalkyl substances (PFAS) are environmentally persistent, potential metabolic disruptors of concern for infants. Mothers participating in the New Hampshire Birth Cohort Study (NHBCS) provided a plasma sample during pregnancy to measure concentrations of seven PFAS, and infant weight and length were abstracted from well-child visits between birth and 12 months. Sex-specific growth patterns of child body mass index (BMI) were fit using a growth mixture model (GMM) and the relative risk ratios (RRR) and 95% Confidence Intervals (95% CI) for the association of maternal plasma PFAS with BMI growth patterns during infancy were estimated by using multinomial logistic model for the group probabilities in the GMM. Four growth patterns were identified: Group 1) a steep increase in BMI during the first 6 months, then a leveling off; Group 2) a gradual increase in BMI across the year; Group 3) a steep increase in BMI during months 1–3, then stable BMI; and Group 4) a gradual increase in BMI with plateau around 3 months (reference group). For boys, higher maternal pregnancy perfluorooctanoate concentrations were associated with a 60% decreased chance of being in group 3 as compared to group 4, after adjusting for potential confounding variables (RRR = 0.4; 95% CI: 0.1, 0.9). For girls, higher maternal perfluorooctane sulfonate (PFOS) concentrations during pregnancy were associated with a higher likelihood of following the growth pattern of groups 2 (RRR = 2.5; 95% CI: 1.0, 6.1) and 3 (RRR = 2.8; 95% CI: 1.0, 7.6) as compared to group 4, adjusting for potential confounding variables. In this cohort, sex-specific associations of maternal plasma PFAS concentrations during pregnancy with growth patterns during the first year of life were observed, with greater BMI growth observed among infant girls born to mothers with higher pregnancy concentrations of PFOS.
Vast numbers of microorganisms inhabit the mammalian gastrointestinal tract in a complex community referred to as the gut microbiome. An individual’s microbiome may be impacted by genetics, diet, and various environmental factors, and has been associated with many health states and diseases, though specific explanations are lacking. While these communities are well-studied in human populations, non-human primates (NHPs), in particular zoo-resident or captive NHPs, offer distinct advantages to increasing our understanding of factors that influence gut microbiome composition. Here, we characterize the gut microbiome composition of a phylogenetically diverse cohort of NHPs residing in the same urban zoo. We show that despite overlapping and controlled environmental contexts, gut microbiomes are still distinguished between NHP host species. However, when comparing the zoo cohort to wild NHPs, we show that captivity status strongly distinguishes zoo-resident NHPs from their wild counterparts, regardless of host phylogeny. Microbial orders unique to captive NHPs include taxa commonly present in human gut microbiomes. Together, these results demonstrate that differences between NHP species are strongly associated with gut microbiome composition and diversity, suggesting that species-specific approaches should be considered when investigating environmental factors’ influence on gut microbiome composition.
We use difference‐in‐differences approaches and parcel‐level data from Minneapolis to estimate the effects of light rail on land use change using alternate definitions of treatment area. Results using circular buffers corroborate previous findings that light rail has virtually no effect on land use change in our study area. In contrast, light rail increases the likelihood of land use change along arterial streets that cross the line at station areas. To accurately model the effects of public transit projects on urban land use, one must consider how potential riders access station areas, rather than assuming accessibility improves radially around a station. This article is protected by copyright. All rights reserved
Amidst an unprecedented swell in global protest, scholars and activists wrestle with the question of why protests succeed or fail. I explore a new answer: more cohesive crowds, where protesters agree on their demands, are more likely to win concessions than less cohesive crowds. Drawing on psychology and linguistics, I theorize that cohesive demands are more comprehensible and thus persuasive. I test this theory with a multimethod approach. First, I use cross‐national data from 97 protests to estimate the relationship between crowd cohesion and subsequent concessions, applying natural language processing to measure cohesion in participants’ self‐reported motivations. Second, a survey experiment in South Africa tests the causal effects of crowd cohesion and assesses comprehensibility of demands as the mechanism driving concessions. Third, case studies of two British protests demonstrate the theory in real‐world settings. My findings suggest that activists can improve their odds of success by coordinating around a common goal.
Millions of people depend on ecosystem services provided by Tropical Dry Forests (TDFs), yet their proximity to population centers, seasonally dry climate, and the ease at which they are converted to agriculture has left only 10 % of their original extent globally. As more TDFs become protected, basic information relating TDF age to subsurface water resources will help guide forest recovery. Severe deforestation and recent reforestation around Bahía de Caráquez, Ecuador produced a mosaic of different successional stages ideal for exploring relationships between TDF age, subsurface water availability and species-specific responses to seasonal drought. Over one year, we measured gravimetric water content, predawn and midday leaf water potential, and the stable isotope composition of xylem and source waters in two regenerating and one primary forest. Over the transition from wet to dry season, we discovered a sharper decrease in predawn water potential in younger successional forests than in the primary forest. Growing in degraded subsurface environments under increased competition, successional forest trees accessed deeper sources of moisture from unsaturated weathered bedrock and groundwater through the dry season; however, different species employed distinct water use strategies. Ceiba trichistandra maintained midday water potentials above −1.27 MPa through a drought avoidance strategy dependent on groundwater. Sideroxylon celastrinum tolerated drought by lowering predawn and midday water potential through the early dry season but took up greater proportions of saprolite moisture and groundwater as the dry season progressed. Contrastingly, Handroanthus chrysanthus maintained access to shallow soil and saprolite moisture by dropping midday water potential to −4.30 MPa, reflecting drought tolerance. Our results show that limited subsurface water resources in regenerating TDF's lead to species-specific adaptations reliant on deeper sources of moisture. The recovery of soil and saprolite hydrologic properties following disturbances is likely to exceed 100 years, highlighting the importance of forest conservation.
The D ⁵ Π-X ⁵ Δ (0,0) band of vanadium hydride at 654 nm has been recorded by laser excitation spectroscopy and represents the first analyzed spectrum of VH in the gas phase. The molecules were generated using a hollow cathode discharge source, with laser-induced fluorescence detected via the D ⁵ Π-A ⁵ Π (0,0) transition. All five main (ΔΩ = ΔΛ) subbands were observed as well as with several satellite ones, which together create a rather complex and overlapped spectrum covering the region 15180-15500 cm ⁻¹ . The D ⁵ Π state displays the effects of three strong local perturbations, which are likely caused by interactions with high vibrational levels of the B ⁵ Σ ⁻ and c ³ Σ ⁻ states, identified in a previous multiconfigurational self-consistent field study by Koseki et al. [J. Phys. Chem. A 108, 4707 (2004)]. Molecular constants describing the X ⁵ Δ, A ⁵ Π, and D ⁵ Π states were determined in three separate least-squares fits using effective Hamiltonians written in a Hund's case (a) basis. The fine structure of the ground state is found to be consistent with its assignment as a σπ ² δ, ⁵ Δ electronic state. The fitted values of its first-order spin-orbit and rotational constants in the ground state are A = 36.5378 cm ⁻¹ and B = 5.7579 cm ⁻¹ , the latter of which yields a bond length of R 0 = 1.7212(2) Å. This experimental value is in good agreement with previous computational studies of the molecule and fits well within the overall trend of decreasing bond length across the series of 3d transition metal monohydrides.
The East Asian monsoon (EAM) and El Niño-Southern Oscillation (ENSO) are large-scale oceanic-atmospheric fluctuations that dominate climate variability in the tropical Pacific Ocean. Although the effects of EAM and ENSO on physical and biological processes are increasingly understood, little is known about their influence on seawater carbonate chemistry in the tropical Pacific, especially in the geological past. Here, we present reconstructed variations in surface-water pCO 2 (pCO 2(sw)) and their deviation from atmospheric pCO 2 (DpCO 2(sw-atm)) in the western Philippine Sea (WPS) since 27 ka. Our record displays covariation between DpCO 2(sw-atm) and the intensity of the East Asian summer monsoon (EASM) since the Last Glacial Maximum (LGM), suggesting that EASM-driven upwelling controls long-term changes in surface-water carbonate chemistry and air-sea CO 2 fluxes. Rapid changes in DpCO 2(sw-atm) were linked to the ENSO-like state and, to a lesser extent, the East Asian winter monsoon (EAWM) during the Last Deglaciation, with low values corresponding to La Niña-like phases and strong EAWM during Heinrich Event 1, the Allerød and the Younger Dryas, and high values corresponding to El Niño-like phases and weak EAWM during the Bølling and Pre-Boreal. This interpretation is supported by the relationship of EAM and ENSO to modern surface-water carbonate chemistry in the WPS. Our new record, combined with previously published data, suggests that the tropical Pacific played a minimal role in sequestering CO 2(atm) during the LGM. Tropical Pacific surface waters overall became a pronounced CO 2 source to the atmosphere during the Last Deglaciation, possibly making a substantial contribution to the deglacial pCO 2(atm) rise. We infer that this flux was mainly due to ENSO-related patterns of vertical stratification or lateral advection, perhaps in addition to equatorial upwelling of southern-sourced waters already enriched in dissolved inorganic carbon. Our findings indicate that tropical conditions (i.e., EAM and ENSO-like state) played a crucial role in glacial-interglacial pCO 2(atm) changes, suggesting that this is an important area for future research into the causes of glacial pCO 2(atm) cycles.
The acetylperoxy + HO2 reaction has multiple impacts on the troposphere, with a triplet pathway leading to peracetic acid + O2 (reaction (1a)) competing with singlet pathways leading to acetic acid + O3 (reaction (1b)) and acetoxy + OH + O2 (reaction (1c)). A recent experimental study has reported branching fractions for these three pathways (α1a, α1b, and α1c) from 229 K to 294 K. We constructed a theoretical model for predicting α1a, α1b, and α1c using quantum chemical and Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) simulations. Our main quantum chemical method was Weizmann-1 Brueckner Doubles (W1BD) theory; we combined W1BD and equation-of-motion spin-flip coupled cluster (SF) theory to treat open-shell singlet structures. Using RRKM/ME simulations that included all conformers of acetylperoxy-HO2 pre-reactive complexes led to a 298 K triplet rate constant, k1a = 5.11 × 10-12 cm3 per molecule per s, and values of α1a in excellent agreement with experiment. Increasing the energies of all singlet structures by 0.9 kcal mol-1 led to a combined singlet rate constant, k1b+1c = 1.20 × 10-11 cm3 per molecule per s, in good agreement with experiment. However, our predicted variations in α1b and α1c with temperature are not nearly as large as those measured, perhaps due to the inadequacy of SF theory in treating the transition structures controlling acetic acid + O3 formation vs. acetoxy + OH + O2 formation.
Lakes are classified by thermal mixing regimes, with shallow waterbodies historically categorized as continuously mixing systems. Yet, recent studies demonstrate extended summertime stratification in ponds, underscoring the need to reassess thermal classifications for shallow waterbodies. In this study, we examined the summertime thermal dynamics of 34 ponds and shallow lakes across temperate North America and Europe to categorize and identify the drivers of different mixing regimes. We identified three mixing regimes: rarely (n = 18), intermittently (n = 10), and often (n = 6) mixed, where waterbodies mixed an average of 2%, 26%, and 75% of the study period, respectively. Waterbodies in the often mixed category were larger (≥4.17 ha) and stratification weakened with increased wind shear stress, characteristic of “shallow lakes.” In contrast, smaller waterbodies, or “ponds,” mixed less frequently, and stratification strengthened with increased shortwave radiation. Shallow ponds (<0.74 m) mixed intermittently, with daytime stratification often breaking down overnight due to convective cooling. Ponds ≥0.74 m deep were rarely or never mixed, likely due to limited wind energy relative to the larger density gradients associated with slightly deeper water columns. Precipitation events weakened stratification, even causing short‐term mixing (hours to days) in some sites. By examining a broad set of shallow waterbodies, we show that mixing regimes are highly sensitive to very small differences in size and depth, with potential implications for ecological and biogeochemical processes. Ultimately, we propose a new framework to characterize the variable mixing regimes of ponds and shallow lakes.
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1,277 members
Shilad Sen
  • Department of Mathematics, Statistics, and Computer Science
Dan Hornbach
  • Department of Environmental Studies
Raymond R Rogers
  • Department of Geology
Vittorio Addona
  • Department of Mathematics, Statistics, and Computer Science
Dennis D Cao
  • Department of Chemistry
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