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

Concept: Philadelphia


The emergence in the United States of large-scale “megaregions” centered on major metropolitan areas is a phenomenon often taken for granted in both scholarly studies and popular accounts of contemporary economic geography. This paper uses a data set of more than 4,000,000 commuter flows as the basis for an empirical approach to the identification of such megaregions. We compare a method which uses a visual heuristic for understanding areal aggregation to a method which uses a computational partitioning algorithm, and we reflect upon the strengths and limitations of both. We discuss how choices about input parameters and scale of analysis can lead to different results, and stress the importance of comparing computational results with “common sense” interpretations of geographic coherence. The results provide a new perspective on the functional economic geography of the United States from a megaregion perspective, and shed light on the old geographic problem of the division of space into areal units.

Concepts: Algorithm, United States, Geography, Economics, Space, New York City, Philadelphia, Economic geography


Suicide is a major and continuing public health concern in the United States. During 1999-2015, approximately 600,000 U.S. residents died by suicide, with the highest annual rate occurring in 2015 (1). Annual county-level mortality data from the National Vital Statistics System (NVSS) and annual county-level population data from the U.S. Census Bureau were used to analyze suicide rate trends during 1999-2015, with special emphasis on comparing more urban and less urban areas. U.S. counties were grouped by level of urbanization using a six-level classification scheme. To evaluate rate trends, joinpoint regression methodology was applied to the time-series data for each level of urbanization. Suicide rates significantly increased over the study period for all county groupings and accelerated significantly in 2007-2008 for the medium metro, small metro, and non-metro groupings. Understanding suicide trends by urbanization level can help identify geographic areas of highest risk and focus prevention efforts. Communities can benefit from implementing policies, programs, and practices based on the best available evidence regarding suicide prevention and key risk factors. Many approaches are applicable regardless of urbanization level, whereas certain strategies might be particularly relevant in less urban areas affected by difficult economic conditions, limited access to helping services, and social isolation.

Concepts: Demography, Population, United States, Urban area, Washington, D.C., Suicide, Philadelphia, United States Census


The website Sci-Hub enables users to download PDF versions of scholarly articles, including many articles that are paywalled at their journal’s site. Sci-Hub has grown rapidly since its creation in 2011, but the extent of its coverage was unclear. Here we report that, as of March 2017, Sci-Hub’s database contains 68.9% of the 81.6 million scholarly articles registered with Crossref and 85.1% of articles published in toll access journals. We find that coverage varies by discipline and publisher, and that Sci-Hub preferentially covers popular, paywalled content. For toll access articles, we find that Sci-Hub provides greater coverage than the University of Pennsylvania, a major research university in the United States. Green open access to toll access articles via licit services, on the other hand, remains quite limited. Our interactive browser at allows users to explore these findings in more detail. For the first time, nearly all scholarly literature is available gratis to anyone with an Internet connection, suggesting the toll access business model may become unsustainable.

Concepts: United States, Academic publishing, Peer review, Literature, Publishing, Portable Document Format, Philadelphia, Open access journal


To evaluate the geographic distribution of assisted reproductive technology (ART) clinics and the number of ART clinics within U.S. Census metropolitan areas and to estimate the number of reproductive-age women who have geographic access to ART services in the United States.

Concepts: European Union, Demography, United States, Poverty in the United States, U.S. state, New York City, Massachusetts, Philadelphia


This paper presents race-specific breast cancer mortality rates and the corresponding rate ratios for the 50 largest U.S. cities for each of the 5-year intervals between 2005 and 2014.

Concepts: United States, California, Native Americans in the United States, Texas, Los Angeles, Chicago, Houston, Philadelphia


Beginning in the late 1870s, before the invention of movie cameras or projectors, pioneering English American photographer Eadweard Muybridge photographed iconic image sequences of people and animals in motion using arrays of sequentially triggered single-image cameras. In 1885, Philadelphia neurologist Francis Dercum initiated a collaborative relationship with Muybridge at the University of Pennsylvania to photograph sequential images of patients with various neurologic disorders of movement, including an acquired pathologic quadrupedal gait in a young boy that developed as a consequence of poliomyelitis.

Concepts: Series, Sequence, Photography, Camera, Photograph, Philadelphia, Eadweard Muybridge


Recent analyses suggest that increases in rates of childhood obesity have plateaued nationally and may be decreasing among certain populations and communities, including Philadelphia, Pennsylvania. We examined 7 years of data, including 3 years not previously reported, to assess recent trends in major demographic groups.

Concepts: Nutrition, Diabetes mellitus, Demography, Obesity, Bariatrics, Childhood obesity, Pennsylvania, Philadelphia


We describe a new cryptic species of leopard frog from the New York City metropolitan area and surrounding coastal regions. This species is morphologically similar to two largely parapatric eastern congeners, Rana sphenocephala and R. pipiens. We primarily use bioacoustic and molecular data to characterize the new species, but also examine other lines of evidence. This discovery is unexpected in one of the largest and most densely populated urban parts of the world. It also demonstrates that new vertebrate species can still be found periodically even in well-studied locales rarely associated with undocumented biodiversity. The new species typically occurs in expansive open-canopied wetlands interspersed with upland patches, but centuries of loss and impact to these habitats give some cause for conservation concern. Other concerns include regional extirpations, fragmented extant populations, and a restricted overall geographic distribution. We assign a type locality within New York City and report a narrow and largely coastal lowland distribution from central Connecticut to northern New Jersey (based on genetic data) and south to North Carolina (based on call data).

Concepts: Population, New York City, New Jersey, New York metropolitan area, Metropolitan area, New York, Rana, Philadelphia


To describe variability in the burden of firearm violence by race, income, and place in an urban context.

Concepts: Pennsylvania, Philadelphia, Urban design


We measured dynamic stress responses using ambulatory heart rate monitoring as participants in Philadelphia, Pennsylvania walked past vacant lots before and after a greening remediation treatment of randomly selected lots. Being in view of a greened vacant lot decreased heart rate significantly more than did being in view of a nongreened vacant lot or not in view of any vacant lot. Remediating neighborhood blight may reduce stress and improve health. (Am J Public Health. Published online ahead of print March 19, 2015: e1-e5. doi:10.2105/AJPH.2014.302526).

Concepts: Walking, Treadmill, Walkability, Philadelphia