1,624 research outputs found
Collaborators for Emancipation: Abraham Lincoln and Owen Lovejoy
Reexamining Lincoln’s Relationship with Abolitionism
The Catholic writer G.K. Chesterton once said that, “To very great minds the things on which men agree are so immeasurably more important than the things on which they differ, that the latter, for all practical purposes, disappear. Will...
The millisecond pulsar mass distribution: Evidence for bimodality and constraints on the maximum neutron star mass
The mass function of neutron stars (NSs) contains information about the late
evolution of massive stars, the supernova explosion mechanism, and the
equation-of-state of cold, nuclear matter beyond the nuclear saturation
density. A number of recent NS mass measurements in binary millisecond pulsar
(MSP) systems increase the fraction of massive NSs (with M)
to of the observed population. In light of these results, we
employ a Bayesian framework to revisit the MSP mass distribution. We find that
a single Gaussian model does not sufficiently describe the observed population.
We test alternative empirical models and infer that the MSP mass distribution
is strongly asymmetric. The diversity in spin and orbital properties of
high-mass NSs suggests that this is most likely not a result of the recycling
process, but rather reflects differences in the NS birth masses. The asymmetry
is best accounted for by a bimodal distribution with a low mass component
centred at M and dispersed by
M, and a high-mass component with a mean of
and a dispersion of
M. We also establish a lower limit of M
at 98% C.L. for the maximum NS mass, from the absence of a high-mass truncation
in the observed masses. Using our inferred model, we find that the measurement
of 350 MSP masses, expected after the conclusion of pulsar surveys with the
Square-Kilometre Array, can result in a precise localization of a maximum mass
up to 2.15 M, with a 5% accuracy. Finally, we identify possible
massive NSs within the known pulsar population and discuss birth masses of
MSPs.Comment: submitted to ApJ; 21 pages in aastex6 two-column format, 12 figures,
5 tables. Comments are welcom
The Cape Porcupine Complex, northern mainland Nova Scotia – no longer a geological orphan
The Cape Porcupine Complex west of the Strait of Canso in northern mainland Nova Scotia consists of mainly fault-bounded units of metasedimentary, metavolcanic, and granitoid rocks. A previously reported U-Pb (zircon) age of 610 ± 3 Ma from syenogranite combined with petrological characteristics indicates that some of the granitic rocks and possibly an associated body of leucodiorite are Late Neoproterozoic. In contrast, alkali-feldspar granite from a more extensive suite of quartz alkali-feldspar syenite/alkali-feldspar syenite, alkali-feldspar granite/syenogranite, and quartz alkali-feldspar leucosyenite with A-type characteristics yielded an early Ordovician age of 478 ± 3 Ma. Similar A-type chemical characteristics suggest that the metavolcanic unit may be the extrusive equivalent of the Ordovician suite.Similarities in age and petrological characteristics indicate that the Cape Porcupine Complex is linked to rock units in the Antigonish Highlands. The ca. 610 Ma granitic rocks are likely related to plutonic and volcanic rocks of similar age in the Antigonish Highlands interpreted to have formed at a continental margin subduction zone. In contrast the A-type syenitic and metavolcanic rocks are probably related to the compositionally similar West Barneys River plutonic suite and younger volcanic rocks formed in an extensional regime. Such rocks do not occur in adjacent Ganderia or Avalonia in Cape Breton Island or southern New Brunswick, further demonstrating the regional significance of the Canso Fault in tectonic reconstructions.RÉSUMÉSitué à l’ouest du détroit de Canso au nord de la partie continentale de la Nouvelle-Écosse, le complexe du cap Porcupine se compose principalement d’unités rocheuses métasédimentaires, métavolcaniques et de granitoïdes limitées par des failles. Une datation réalisée précédemment par la méthode U-Pb sur zircon et qui a établi un âge de 610 ± 3 Ma à partir du syénogranite et des caractéristiques pétrologiques indique qu’une partie des roches de granite et vraisemblablement un corps connexe de leucodiorite sont du Néoprotérozoïque tardif. Par contraste, du granite de feldspath alcalin d’une succession plus importante de syénite de feldspath alcalin quartzeux/syénite de feldspath alcalin, de granite de feldspath alcalin/syénogranite, et de leucosyénite de feldspath alcalin quartzeux présentant des caractéristiques de type A a produit un âge de l’Ordovicien précoce, soit environ 478 ± 3 Ma. Ces caractéristiques chimiques de type A analogues portent à croire que l’unité métavolcanique pourrait être l’équivalent extrusif de la succession de l’Ordovicien.Les similitudes de datation et les caractéristiques pétrologiques indiquent que le complexe du cap Porcupine est relié aux unités rocheuses des hautes-terres d’Antigonish. L’âge du granite, d’environ 640 Ma, se rapporterait vraisemblablement aux roches plutoniques et volcaniques de la même époque observées dans les hautes-terres d’Antigonish, dont on suppose qu’elles ont été formées dans une zone de subduction de la marge continentale. Par contraste, les roches métavolcaniques et syénitiques de type A sont probablement reliées par la similitude de leur composition au cortège plutonique et aux roches volcaniques plus jeunes de la rivière Barneys Ouest formées dans un milieu de distension. Ces roches ne sont pas présentes dans la partie adjacente de Ganderia ou d’Avalonia sur l’île du Cap-Breton ou dans le sud du Nouveau-Brunswick, ce qui tendrait à souligner encore plus l’importance régionale de la faille de Canso dans les reconstructions tectoniques.[Traduit par la redaction
Optically Transparent Composite Material and Process for Preparing Same
Glass ribbon-reinforced transparent polymer composites which provide excellent optical transparency and a low distortion level over a wide temperature range while exhibiting superior mechanical properties as compared to non- reinforced polymer counterparts, and equivalent properties as compared to glass fiber-reinforced counterparts
2013 Exit Survey of Graduate Students Completing Degrees Fall 2012, Winter 2013, Spring 2013, and Summer 2013: Descriptive Statistics
The 2013 Exit Survey of Graduate Students Completing Degrees continues the Office of Survey Research’s (OSR) survey of graduate students first initiated in 2009. The current survey was administered at the end of each quarter to students completing their graduate degree. This report summarizes responses from students who graduated in Fall 2012, Winter 2013, Spring 2013, and Summer 2013. Of the 266 recipients of this degree during this time, OSR received valid responses from 204, a response rate of 76.7%. Interestingly, while this response rate is higher than those from the Graduate Exit Surveys in the past, Western had fewer total graduate students complete their degrees between Fall 2012 and Summer 2013 than in either of the prior two years resulting in fewer total responses to this survey than in prior years. With the help of the Assistant Dean of the Graduate School, this survey was designed to elicit information on program satisfaction, the frequency and scope of academic interaction on and off campus, barriers to success, and plans for the future. OSR uses a mixture of online and telephone survey methodologies and links survey results with Western’s student records thus expanding their usefulness to researchers and university decision makers. The survey was launched with an e-mail invitation to potential respondents about four weeks prior to the end of each quarter. Follow up e-mail reminders were sent approximately every four days for the subsequent two weeks. Phone call reminders were placed to all non-respondents. The survey was closed immediately prior to commencement exercises. As with any survey, readers should be concerned with sample selection bias; that is bias which arises because survey respondents are not a random selection of the population of survey recipients. While sample selection bias for Western’s graduate exit survey is mitigated through proper survey techniques and limited by a high response rate, its presence should continually be kept in mind when evaluating results. Section A of this document presents basic descriptive statistics that compare all graduates with those who responded to the survey. At the university level, these comparisons reveal that the average respondent is nearly identical to the average graduate. For instance, 13% of respondents are minorities compared to 13% of all graduates. Similar results occur for average age (30.3 years for respondents, 30.7 years for graduates), the number of credit hours attempted (68.9 for respondents and 69.7 for graduates), the average graduate GPA (3.79 for respondents and 3.80 for graduates), and the quarter of graduation. Section B of this report presents all questions asked. Section C presents these questions broken down by college and,Sections D through G are further broken down to the departmental level for departments with enough respondents to prevent identification of individuals. Because CBE has only a single graduate program, we do not break their responses down further than the college level. While we leave it to the reader to determine what is interesting in the survey, here we highlight some of the findings. The first set of questions is geared to understanding students’ background and general satisfaction with their Western graduate school experience. Immediately prior to beginning their Western graduate program 36% of students were in an undergraduate program, 33% were employed in a field related to their graduate program, and 26% were employed in a field different than their program. Results are very similar to prior surveys. Sixty-nine percent of students claimed that, if given the opportunity, they would “probably” or “definitely” select Western again for graduate study, an amount similar to the 2012 survey but a decrease of five percent relative to the 2011 survey. Seventy percent would “probably” or “definitely” recommend Western to someone considering graduate school, a decrease of five percent relative to the prior year and nine percent lower than two years ago. Survey questions also relate to a student’s academic program. For instance, 86% of students reported that the level of academic challenge was “very” or “extremely” important to them and 73% of students claimed they were “satisfied “or “very satisfied “with the level of academic challenge. Perhaps the largest disparity occurred among the 74% of students who claimed that the “quality of instruction” was “extremely important” to them but only 26% of students said they were “very satisfied” with the quality of instruction. Working as a teaching assistant remains an important component of Western’s graduate program. Forty-six percent of respondents reported working as a TA in some capacity while pursuing their graduate degree. In their most recent TA position, respondents reported working an average of 18.5 hours per week. Eleven percent of graduate students taught an independent section of an undergraduate class; among these the median graduate student repeated this experience 6 times while in Western’s graduate program. The average graduate accumulates just over 28,300. There is large variation in amounts of student debt incurred between colleges. Graduates of CHSS incur 50% more debt that those of CBE who, in turn, accumulate about twice as much debt than students in CST. Among all graduate students, almost two-fifths hope to work in a school or community college. The remainders are fairly evenly split between non-profit employment, government employment, and pursuing further graduate study. Among those pursuing employment, at the time our survey was conducted, 45% had already received an offer of employment and 85% of those had accepted an offer. One-hundred percent of these had jobs in their field of study. As with all of OSR’s surveys of Western students, the data from this survey is available to campus researchers upon request
Pediatric Transplantation in the United States, 1996–2005
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73448/1/j.1600-6143.2007.01780.x.pd
Proteomic Analysis of a Noninvasive Human Model of Acute Inflammation and Its Resolution: The Twenty-one Day Gingivitis Model
The 21-day experimental gingivitis model, an established noninvasive model of inflammation in response to increasing bacterial accumulation in humans, is designed to enable the study of both the induction and resolution of inflammation. Here, we have analyzed gingival crevicular fluid, an oral fluid comprising a serum transudate and tissue exudates, by LC−MS/MS using Fourier transform ion cyclotron resonance mass spectrometry and iTRAQ isobaric mass tags, to establish meta-proteomic profiles of inflammation-induced changes in proteins in healthy young volunteers. Across the course of experimentally induced gingivitis, we identified 16 bacterial and 186 human proteins. Although abundances of the bacterial proteins identified did not vary temporally, Fusobacterium outer membrane proteins were detected. Fusobacterium species have previously been associated with periodontal health or disease. The human proteins identified spanned a wide range of compartments (both extracellular and intracellular) and functions, including serum proteins, proteins displaying antibacterial properties, and proteins with functions associated with cellular transcription, DNA binding, the cytoskeleton, cell adhesion, and cilia. PolySNAP3 clustering software was used in a multilayered analytical approach. Clusters of proteins that associated with changes to the clinical parameters included neuronal and synapse associated proteins
2012 Exit Survey of Graduate Students Completing Degrees Fall 2012, Winter 2012, Spring 2012, and Summer 2012: Descriptive Statistics
The 2012 Exit Survey of Graduate Students Completing Degrees continues the Office of Survey Research’s (OSR) survey of Graduate students first initiated in 2009. The current survey was administered at the end of each quarter to students completing their graduate degree. This report summarizes responses from students who graduated in Fall 2011, Winter 2012, Spring 2012, and Summer 2012. Of the 343 recipients of this degree during this time, OSR received valid responses from 247 (a response rate of 72.0%). With the help of the Assistant Dean of the Graduate School, this survey was designed to elicit information on program satisfaction, the frequency and scope of academic interaction on and off campus, barriers to success, and plans for the future. OSR uses a mixture of online and telephone survey methodologies and links survey results with Western’s student records thus expanding their usefulness to researchers and university decision makers. The survey was launched with an e-mail invitation to potential respondents about four weeks prior to the end of each quarter. Follow up e-mail reminders were sent approximately every four days for the subsequent two weeks. Phone call reminders were placed to all non-respondents. The survey was closed immediately prior to commencement exercises. As with any survey, readers should be concerned with sample selection bias; that is bias which arises because survey respondents are not a random selection of the population of survey recipients. While sample selection bias for Western’s graduate exit survey is mitigated through proper survey techniques and limited by a high response rate, its presence should continually be kept in mind when evaluating results. Section A of this document presents basic descriptive statistics that compare all graduates with those who responded to the survey. At the university level, these comparisons reveal that the average respondent is nearly identical to the average graduate. For instance, 10% of respondents are minorities compared to 11% of all graduates. Similar results occur for average age (30.7 years for respondents, 30.5 years for graduates), the number of credit hours attempted (69.3 for respondents and 68.8 for graduates), the average graduate GPA (3.76 for respondents and 3.75 for graduates), and the quarter of graduation. Section B of this report presents all questions asked. Section C presents these questions broken down by college and, for questions with enough responses to prevent identification of individuals, these are further broken down to the departmental level in Sections D through H. Because CBE has only a single graduate program, we do not break their responses down further than the college level. As CFPA had a small number of graduates, these responses were included in the overall WWU results but, in order to protect student anonymity, were not disaggregated into a college report. While we leave it to the reader to determine what is interesting in the survey, here we highlight some of the findings. The first set of questions is geared to understanding students’ background and general satisfaction with their Western graduate school experience. Immediately prior to beginning their Western graduate program 34% of students were in an undergraduate program, 37% were employed in a field related to their graduate program, and 25% were employed in a field different than their program. Results are very similar to prior surveys. Sixty-Eight percent of students claimed that, if given the opportunity, they would “probably” or “definitely” select Western again for graduate study, a decrease of six percent relative to the 2011 survey. Seventy-five percent would “probably” or “definitely” recommend Western to someone considering graduate school, a decrease of four percent relative to the prior year. Survey questions also relate to a student’s academic program. For instance, 86% of students reported that the level of academic challenge was “very” or “extremely” important to them and 77% of students claimed they were “satisfied” or “very satisfied” with the level of academic challenge they encountered. Seventy-eight percent were satisfied or very satisfied with their program. The most commonly reported barrier to academic progress was family obligations. Almost two-thirds of respondents claimed the availability (or lack thereof ) of faculty had no impact on their progress towards their degree, a significant increase over the prior year. The average graduate accumulates just over 25,000. There is large variation in amounts of student debt incurred between colleges. Graduates of CHSS incur 50% more debt that those of CBE who, in turn, accumulate about 50% more debt than students in CST. One benefit of the graduate exit survey is that the data is tracked by a unique student identifier which allows OSR to divide the data by school or program. OSR hopes to share this data with administrators and individuals who hope to improve their programs
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