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State College, PA, United States

Swarthmore College is a highly selective, private liberal arts college located in Swarthmore, Pennsylvania, 11 miles southwest of Philadelphia. Its history, academic influence, and reputation make it one of the leading colleges in the United States.Founded in 1864, Swarthmore was one of the earliest coeducational colleges in the United States. The school was organized by a Committee of "Quakers" from three "Hicksite" yearly meetings: Baltimore, New York, and Philadelphia. Many of the founders were prominent in the abolitionist and women's rights movements and other social concerns and included Edward Parrish, , Deborah and Joseph Wharton, Benjamin Hallowell, and James and Lucretia Mott, . Swarthmore was established to be a college, "...under the care of Friends, at which an education may be obtained equal to that of the best institutions of learning in our country." By 1906 Swarthmore dropped its religious affiliation, becoming officially non-sectarian.Today, the college is known for rigorous academics, widely advertised commitment to social responsibility, and the legacy of its Quaker roots. Ninety percent of graduates eventually attend graduate or professional school, and over twenty percent of graduates attain a Doctor of Philosophy degree in their lifetime, rates among the highest of US institutions.Swarthmore is a member of the "Tri-College Consortium", a cooperative arrangement among Swarthmore, Bryn Mawr, and Haverford Colleges. The consortium shares an integrated library system of more than three million volumes, and students are able to cross-register in courses at all three institutions. A common Quaker heritage exists amongst the consortium schools and the University of Pennsylvania also extends this cross-registration agreement to classes at the University of Pennsylvania's College of Arts and science.Swarthmore's campus and the Scott Arboretum share the same borders. Wikipedia.


Akeson R.L.,NASA | Jensen E.L.N.,Swarthmore College
Astrophysical Journal | Year: 2014

We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10-4 M ⊙. We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of Fmm α * 1.5-2.0 to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions. © 2014. The American Astronomical Society. All rights reserved. Source


Kostelecky V.A.,Indiana University Bloomington | Mewes M.,Swarthmore College
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The theoretical description of fermions in the presence of Lorentz and CPT violation is developed. We classify all Lorentz- and CPT-violating and invariant terms in the quadratic Lagrange density for a Dirac fermion, including operators of arbitrary mass dimension. The exact dispersion relation is obtained in closed and compact form, and projection operators for the spinors are derived. The Pauli Hamiltonians for particles and antiparticles are extracted, and observable combinations of operators are identified. We characterize and enumerate the coefficients for Lorentz violation for any operator mass dimension via a decomposition using spin-weighted spherical harmonics. The restriction of the general theory to various special cases is presented, including isotropic models, the nonrelativistic and ultrarelativistic limits, and the minimal Standard-Model Extension. Expressions are derived in several limits for the fermion dispersion relation, the associated fermion group velocity, and the fermion spin-precession frequency. We connect the analysis to some other formalisms and use the results to extract constraints from astrophysical observations on isotropic ultrarelativistic spherical coefficients for Lorentz violation. © 2013 American Physical Society. Source


Cota C.D.,Swarthmore College
Briefings in functional genomics | Year: 2014

Defects in the initial establishment of cardiogenic cell fate are likely to contribute to pervasive human congenital cardiac abnormalities. However, the molecular underpinnings of nascent cardiac fate induction have proven difficult to decipher. In this review we explore the participation of extracellular, cellular and nuclear factors in comprehensive specification networks. At each level, we elaborate on insights gained through the study of cardiogenesis in the invertebrate chordate Ciona intestinalis and propose productive lines of future research. In-depth discussion of pre-cardiac induction is intended to serve as a paradigm, illustrating the potential use of Ciona to elucidate comprehensive networks underlying additional aspects of chordate cardiogenesis, including directed migration and subspecification of cardiac and pharyngeal lineages. Source


Johnson R.H.,University of Washington | Chien F.L.,University of Washington | Chien F.L.,Swarthmore College | Bleyer A.,Oregon Health And Science University
JAMA - Journal of the American Medical Association | Year: 2013

Importance: Evidence from the US National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database suggests that the incidence of advanced breast cancer in young women is increasing. Objective: To quantify this trend and analyze it as a function of stage at diagnosis, race/ethnicity, residence, and hormone receptor status. Design, Setting, and Patients: Breast cancer incidence, incidence trends, and survival rates as a function of age and extent of disease at diagnosis were obtained from 3 SEER registries that provide data spanning 1973-2009, 1992-2009, and 2000-2009. SEER defines localized as disease confined to the breast, regional to contiguous and adjacent organ spread (eg, lymph nodes, chest wall), and distant disease to remote metastases (bone, brain, lung, etc). Main Outcome Measure: Breast cancer incidence trends in the United States. Results: In the United States, the incidence of breast cancer with distant involvement at diagnosis increased in 25- to 39-year-old women from 1.53 (95% CI, 1.01 to 2.21) per 100 000 in 1976 to 2.90 (95% CI, 2.31 to 3.59) per 100 000 in 2009. This is an absolute difference of 1.37 per 100 000, representing an average compounded increase of 2.07% per year (95% CI, 1.57% to 2.58%; P<.001) over the 34-year interval. No other age group or extent-of-disease subgroup of the same age range had a similar increase. For 25- to 39-year-olds, there was an increased incidence in distant disease among all races and ethnicities evaluated, especially non-Hispanic white and African American, and this occurred in both metropolitan and nonmetropolitan areas. Incidence for women with estrogen receptor-positive subtypes increased more than for women with estrogen receptor-negative subtypes. Conclusion and Relevance: Based on SEER data, there was a small but statistically significant increase in the incidence of breast cancer with distant involvement in the United States between 1976 and 2009 for women aged 25 to 39 years, without a corresponding increase in older women. ©2013 American Medical Association. All rights reserved. Source


Yee J.C.,Ohio State University | Jensen E.L.N.,Swarthmore College
Astrophysical Journal | Year: 2010

Despite the extensive study of lithium depletion during pre-main-sequence (PMS) contraction, studies of individual stars show discrepancies between ages determined from the Hertzsprung-Russell (H-R) diagram and ages determined from lithium depletion, indicating open questions in the PMS evolutionary models. To further test these models, we present high-resolution spectra for members of the β Pictoris Moving Group (BPMG), which is young and nearby. We measure equivalent widths of the 6707.8 Å Li I line in these stars and use them to determine lithium abundances. We combine the lithium abundance with the predictions of PMS evolutionary models in order to calculate a lithium depletion age for each star. We compare this age to the age predicted by the H-R diagram of the same model. We find that the evolutionary models underpredict the amount of lithium depletion for the BPMG given its nominal H-R diagram age of ∼12 Myr, particularly for the mid-M stars, which have no observable Li I line. This results in systematically older ages calculated from lithium depletion isochrones than from the H-R diagram. We suggest that this discrepancy may be related to the discrepancy between measured M-dwarf radii and the smaller radii predicted by evolutionary models. © 2010 The American Astronomical Society. Source

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