Discover the most talked about and latest scientific content & concepts.

Concept: Henry David Thoreau


Flowering times are well-documented indicators of the ecological effects of climate change and are linked to numerous ecosystem processes and trophic interactions. Dozens of studies have shown that flowering times for many spring-flowering plants have become earlier as a result of recent climate change, but it is uncertain if flowering times will continue to advance as temperatures rise. Here, we used long-term flowering records initiated by Henry David Thoreau in 1852 and Aldo Leopold in 1935 to investigate this question. Our analyses demonstrate that record-breaking spring temperatures in 2010 and 2012 in Massachusetts, USA, and 2012 in Wisconsin, USA, resulted in the earliest flowering times in recorded history for dozens of spring-flowering plants of the eastern United States. These dramatic advances in spring flowering were successfully predicted by historical relationships between flowering and spring temperature spanning up to 161 years of ecological change. These results demonstrate that numerous temperate plant species have yet to show obvious signs of physiological constraints on phenological advancement in the face of climate change.

Concepts: Climate, Aldo Leopold, Massachusetts, Henry David Thoreau, United States


To assess the extent to which stage at diagnosis and adherence to treatment guidelines may explain the persistent differences in colorectal cancer survival between the USA and Europe.

Concepts: Henry David Thoreau, Nathaniel Hawthorne, Ralph Waldo Emerson, Cancer, European Union, English language, United States, Colorectal cancer


To examine levels of, correlates of, and changes in the use of individual and grouped methods of contraception among U.S. females aged 15-44 from 2008 to 2014.

Concepts: Ralph Waldo Emerson, Marilyn Monroe, Henry David Thoreau, Humid subtropical climate, U.S. state, Poverty in the United States, United States


Recent shifts in the ecological condition of Walden Pond, MA, are of potentially wide interest due to the lake’s importance as a cultural, historical, and recreational resource in addition to its scientific value as an indicator of local and global environmental change. Algal microfossils in six sediment cores document changes in hydroclimate and trophic status of the lake during the last 1800 years and extend two previous sediment core records of shorter length. Low percentages of planktonic diatoms in the longest cores (WAL-3, WAL-15) indicate shallowing and/or greater water clarity associated with a relatively arid interval during the Medieval Climate Anomaly, ca. A.D. 1150-1300, Cultural eutrophication of the lake since the A.D. 1920s caused diatoms in the genera Asterionella and Synedra to increase in relative abundance at the expense of Cyclotella, Discostella, and the chrysophyte alga Mallomonas allorgei. Percentages of Asterionella and Synedra have remained fairly stable since A.D. 2000 when a previous sediment core study was conducted, but scaled chrysophytes have become more numerous. These findings suggest that, although mitigation efforts have curtailed anthropogenic nutrient inputs to Walden Pond, the lake has not returned to the pre-impact condition described by Henry David Thoreau and may become increasingly vulnerable to further changes in water quality in a warmer and possibly wetter future.

Concepts: Lake, Eutrophication, Walden Pond, Algae, Concord, Massachusetts, Walden, Water pollution, Henry David Thoreau


Recent data suggest that neighborhood socioeconomic environment predicts heart failure (HF) hospital readmissions. We investigated whether neighborhood deprivation predicts risk of incident HF beyond individual socioeconomic status in a low-income population.

Concepts: Black people, Social status, Socioeconomic status, Henry David Thoreau, United States, Cardiology, Sociology, United Kingdom


The detrimental effects of extreme poverty on children’s lives are serious, and they lack simple storybook resolutions. The American Academy of Pediatrics' policy statement on poverty and child health represents an honorable step toward addressing this problem.

Concepts: Prairie, Henry David Thoreau, Humid subtropical climate, U.S. state, Childhood, Child, United States, Poverty in the United States


The U.S. medical malpractice system assumes that the threat of liability should deter negligence but it is unclear whether malpractice environment impacts healthcare quality. We thus sought to explore the association between state malpractice environment and post-operative complication rates.

Concepts: Henry David Thoreau, Barack Obama, Massachusetts, Common law, Humid subtropical climate, Poverty in the United States, U.S. state, United States


We sought to understand the multilevel syndemic factors that are concurrently contributing to the HIV epidemic among women living in the US. We specifically examined community, network, dyadic, and individual factors to explain HIV vulnerability within a socioecological framework.

Concepts: Women's rights, Henry David Thoreau, Passenger vehicles in the United States, Humid subtropical climate, U.S. state, Poverty in the United States, Frank Lloyd Wright, United States


To elucidate climate-driven changes in leaf-out phenology and their implications for species invasions, we observed and experimentally manipulated leaf out of invasive and native woody plants in Concord, MA, USA. Using observations collected by Henry David Thoreau (1852-1860) and our own observations (2009-2013), we analyzed changes in leaf-out timing and sensitivity to temperature for 43 woody plant species. We experimentally tested winter chilling requirements of 50 species by exposing cut branches to warm indoor temperatures (22°C) during the winter and spring of 2013. Woody species are now leafing out an average of 18 d earlier than they did in the 1850s, and are advancing at a rate of 5 ± 1 d °C(-1) . Functional groups differ significantly in the duration of chilling they require to leaf out: invasive shrubs generally have weaker chilling requirements than native shrubs and leaf out faster in the laboratory and earlier in the field; native trees have the strongest chilling requirements. Our results suggest that invasive shrub species will continue to have a competitive advantage as the climate warms, because native plants are slower to respond to warming spring temperatures and, in the future, may not meet their chilling requirements.

Concepts: Transcendentalism, Walden, Massachusetts, Concord, Massachusetts, Shrub, Henry David Thoreau, Tree, Plants


There are concerns whether percutaneous coronary intervention (PCI) at centers without on-site cardiac surgery is safe outside of a tightly regulated research environment.

Concepts: Humid subtropical climate, Henry David Thoreau, Percutaneous coronary intervention, Heart, Cardiology, U.S. state, Poverty in the United States, United States