37495 research outputs found
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Pearl Buck’s Humanitarian Vision in War and Peace
No full textEurasia, that vast continental region that encompasses Europe and Asia, was a tablet for many of Pearl S. Buck’s works and campaigns for human rights and international efforts to improve the human condition globally. Though she is principally known for her works on China, some scholars, while acknowledging that her novels were principally for an American female audience, gave little attention to her significant body of non-fictional works on a variety of subjects on America and East Asia. I made my first trip to China in the summer of 1985 via the Trans-Siberian Railroad and Mongolia to Beijing
Phi Beta Kappa, Psi of California Chapter, Induction Ceremony 2025
No full texthttps://digitalcommons.chapman.edu/pbk_induction_ceremony_2025/1000/thumbnail.jp
Phi Beta Kappa, Psi of California Chapter, Induction Ceremony 2025
No full texthttps://digitalcommons.chapman.edu/pbk_induction_ceremony_2025/1020/thumbnail.jp
Phi Beta Kappa, Psi of California Chapter, Induction Ceremony 2025
No full texthttps://digitalcommons.chapman.edu/pbk_induction_ceremony_2025/1032/thumbnail.jp
Physical Activity Mediates Age Differences in Cognition Among Tsimane Forager-Horticulturalists
No full textBackground: The Tsimane and Moseten of the Bolivian Amazon are highly physically active and exhibit low rates of cognitive impairment and brain atrophy.
Methods: We use structural equation modelling to examine how their physical activity levels mediate the relationship between (1) age and cognition, and (2) age and cognition via brain volume (BV).
Results: Tsimane males (n = 305, mean ± SD age = 59.94 ± 9.68) and Tsimane females (n = 265, mean ± SD age = 59.28 ± 9.79) exhibit significantly higher levels of physical activity than Moseten males (n = 106, mean ± SD age = 58.15 ± 9.93) and Moseten females (n = 96, mean ± SD age = 56.63 ± 9.69). Physical activity significantly mediates the relationship between age and cognition in Tsimane males (indirect effect estimate β = −0.01, P \u3c .01) and Tsimane females (indirect effect estimate β = −0.04, P = .01), but not in Moseten males or females.
Conclusions: Among Tsimane males, who are more physically active than Tsimane females, the association between age and cognition via BV is significantly mediated by physical activity. Among Tsimane females, mediation occurs directly via physical activity, bypassing BV. These results suggest that mechanisms of cognitive differences across ages differ by sex and population. Studying the relationship between brain atrophy and lifestyle in nonindustrialized populations elucidates biological and environmental correlates of brain health
Perceived Neighborhood Cohesion and Well-Being During the COVID-19 Pandemic in the U.S.
No full textThe U.S. entered a “second pandemic” characterized by depression and loneliness after the initial outbreak of COVID-19. These psychological consequences have driven researchers to identify protective factors during this crisis. The present study tested whether perceived neighborhood cohesion, or that neighbors trust and count on one another, related to fewer depressive symptoms and less loneliness as the pandemic unfolded. Two waves of data were collected online from the same adults in April and October, 2020 (N = 1,928). People who reported greater neighborhood cohesion had fewer depressive symptoms (b = −1.01, p \u3c 0.001) and were less lonely (b = −0.20, p \u3c 0.001), even when considering other pandemic-related risk factors. The association between cohesion and loneliness was even stronger 6 months into the pandemic (b = −0.08, p \u3c .001). Working to foster neighborhood cohesion now, so this resource is available before future crises, is a worthwhile goal
High Spatial Resolution Crop Type and Land Use Land Cover Classification without Labels: A Framework Using Multi-temporal PlanetScope Images and Variational Bayesian Gaussian Mixture Model
Full text linkPrevious studies often combined high spatial resolution data (e.g., PlanetScope) with wider spectral range data (e.g., Sentinel-2) and relied on supervised classification methods to produce land use and land cover (LULC) maps. This study proposed a new unsupervised framework to generate crop type and LULC maps at high spatial resolution (\u3c 5 m) using available PlanetScope data solely without requiring ground truths. We used PlanetScope surface reflectance images and their derived spectral indices during growing seasons to create multi-temporal input features, which were fed into an unsupervised Variational Bayesian Gaussian Mixture Model (VBGMM). The VBGMM, unlike the traditional unsupervised classification methods, (1) first estimated optimal parameters that are most suitable based on the input features and then (2) assigned pixels to the cluster with maximum posteriori probability of a mixture of several Gaussian distributions. The crop type and LULC maps were then generated by labeling the derived clusters using the best possible assignment method, referring to the existing crop type or LULC products. We evaluated the produced PlanetScope-based crop type and LULC maps using true labels, corresponding reference maps, and other unsupervised classification methods. The results demonstrated the robustness and effectiveness of the proposed framework in mapping crop types and LULC at 3–5 m pixels across various ecosystems, climate zones, and human-managed landscapes. The spatial patterns of PlanetScope-based maps were (1) highly comparable with all the reference datasets at 10–30 m spatial resolution and (2) better than the traditional GMM and K-means clustering methods. The VBGMM produced classification maps with high confidence, yielding class probabilities above 0.9 for over 90 % of all study areas. The area percentage for all crop type and LULC classes agreed well with their reference maps, with R2 of 0.95 and RMSE of 1.04 %. The confusion matrices using true labels indicated that PlanetScope-based maps achieved a higher overall accuracy of 84 % than the supervised referenced maps of 81 %. Besides, the entropy comparison showed that our framework-based maps were better at capturing fine-scale features such as developed areas within cities that commonly mix with open space and vegetation, deforestation and cropland conversion in South America, smallholder croplands in Africa and Asia, and generating homogeneous crop fields in North America. This study further highlighted the potential for future research to implement our proposed framework to generate timely and extensive annotated datasets, which can be used for operationally training machine learning models to map crop types and LULC, track deforestation, detect wildfires, and delineate flooded areas at larger scales using medium/coarse Earth observations
New Precipitation Is Scarce in Deep Soils: Findings From 47 Forest Plots Spanning Switzerland
Full text linkAs precipitation infiltrates into soils, it can recharge them, displace previously stored waters, or bypass already-filled pores. Using 3,697 δ2H and δ18O measurements of water collected nearly monthly over \u3e3 years in 47 forest plots across Switzerland, we present a systematic investigation of the controls on mobile soil water transport. We quantified the lags and damping of water as it percolates downward using young water fraction analysis (Fyw), and the fractions of soil water composed by precipitation that fell within the previous month (new water fractions, Fnew). The Fnew of water sampled in surface soils ranged widely, from 0% to 50%, but those fractions typically decreased with depth and converged on values of 0%–20% at depths below 80 cm. Soil characteristics explained much of the variation in Fyw and Fnew, as did climatological and root characteristics to a lesser, but still statistically significant, degree
Cryo-EM Structures of the Small-conductance Ca\u3csup\u3e2+\u3c/sup\u3e-activated K\u3csub\u3eCa\u3c/sub\u3e2.2 Channel
Full text linkSmall-conductance Ca2+-activated K+ (KCa2.1-KCa2.3) channels modulate neuronal and cardiac excitability. We report cryo-electron microscopy structures of the KCa2.2 channel in complex with calmodulin and Ca2+, alone or bound to two small molecule inhibitors, at 3.18, 3.50, 2.99 and 2.97 angstrom resolution, respectively. Extracellular S3-S4 loops in β-hairpin configuration form an outer canopy over the pore with an aromatic box at the canopy’s center. Each S3-S4 β-hairpin is tethered to the selectivity filter in the neighboring subunit by inter-subunit hydrogen bonds. This hydrogen bond network flips the aromatic residue (Tyr362) in the filter’s GYG signature by 180°, causing the outer selectivity filter to widen and water to enter the filter. Disruption of the tether by a mutation narrows the outer selectivity filter, realigns Tyr362 to the position seen in other K+ channels, and significantly increases unitary conductance. UCL1684, a mimetic of the bee venom peptide apamin, sits atop the canopy and occludes the opening in the aromatic box. AP14145, an analogue of a therapeutic for atrial fibrillation, binds in the central cavity below the selectivity filter and induces closure of the inner gate. These structures provide a basis for understanding the small unitary conductance and pharmacology of KCa2.x channels
Age–Period–Cohort Effects of Adult Cigarette Smoking in the United States, 1971–2020
Full text linkThe rates of cigarette use among American adults have dropped substantially throughout the last six decades, yet smoking remains the leading cause of preventable disease and death in the United States. It is crucial to identify the putative time-varying population-level factors of age, period, and cohort that influenced the decrease in smoking prevalence so we can maintain the downward trend. We used 49 years of data from the National Health and Nutrition Examination Survey (NHANES) and hierarchical age–period–cohort (HAPC) analysis to examine lifecycle, historical, and generational distribution of smoking among Americans aged 18–74 years old. The prevalence of smoking has declined tremendously from 1971 to 2020 because American adults over the age of ~ 27 had a lower probability of cigarette use, but the rates of decrease have been unequal among birth cohorts. We uncovered the putative temporal contributors to population-level decreases in the prevalence of current smoking among American adults over the last nearly fifty years. Policy-makers ought to prioritize tobacco control efforts that focus on young adults, and should address the cohort-specific challenges in order to maintain the downward trend in smoking prevalence and further reduce the number of preventable premature deaths due to cigarette use