591 research outputs found
Why Neighborhoods (and How We Study Them) Matter for Adolescent Development
Adolescence is a sensitive developmental period marked by significant changes that unfold across multiple contexts. As a central context of development, neighborhoods captureâin both physical and social spaceâthe stratification of life chances and differential distribution of resources and risks. For some youth, neighborhoods are springboards to opportunities; for others, they are snares that constrain progress and limit the ability to avoid risks. Despite abundant research on âneighborhood effects,â scant attention has been paid to how neighborhoods are a product of social stratification forces that operate simultaneously to affect human development. Neighborhoods in the United States are the manifestation of three intersecting social structural cleavages: race/ethnicity, socioeconomic class, and geography. Many opportunities are allocated or denied along these three cleavages. To capture these joint processes, we advocate a âneighborhood-centeredâ approach to study the effects of neighborhoods on adolescent development. Using nationally representative data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), we demonstrate the complex ways that these three cleavages shape specific neighborhood contexts and can result in stark differences in well-being. A neighborhood-centered approach demands more rigorous and sensitive theories of place, as well as multidimensional classification and measures. We discuss an agenda to advance the state of theories and research, drawing explicit attention to the stratifying forces that bring about distinct neighborhood types that shape developmental trajectories during adolescence and beyond
Normative climates of parenthood across Europe : judging voluntary childlessness and working parents
Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Past research on gender role attitudes has often focused on individual- rather than country-level explanations. Drawing on European Social Survey data from 21 countries, we examine the effect of societal normative climates (i.e., shared perceptions of othersâ attitudes) on personal attitudes towards two non-traditional gender roles: Voluntary childlessness and working full-time while children are young. To detect potential gender differences, we analyse disapproval of men and women separately. Findings reveal that there are strong differences in normative climates across countries, and that people generally perceive more disapproval of women than of men for both behaviours. Most importantly, in countries where a higher share of respondents perceives disapproval of these behaviours, respondents themselves disapprove more strongly â even if they do not believe that others disapprove, and even after controlling for other relevant individual- and country-level characteristics. What is more, the independent effect of normative climate explains most of the differences between countries. This robust finding demonstrates the power of country-level normative climates in explaining individualsâ attitudes and between-country differences in attitudes toward gender roles
Picosecond time-resolved pure-rotational coherent anti-Stokes Raman spectroscopy for N-2 thermometry
This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-34-23-3755. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Peer reviewedPublisher PD
Role of Non-Stationary Collisional Dynamics in Determining Nitric Oxide LIF Spectra
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77182/1/AIAA-2004-389-525.pd
Nonstationary Collisional Dynamics in Determining Nitric Oxide Laser-Induced Flourescence Spectra
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77237/1/AIAA-8783-947.pd
âLetâs pull these technologies out of the ivory towerâ: The politics, ethos, and ironies of participant-driven genomic research
This paper investigates how groups of âcitizen scientistsâ in non-traditional settings and primarily online networks claim to be challenging conventional genomic research processes and norms. Although these groups are highly diverse, they all distinguish their efforts from traditional university- or industry-based genomic research as being âparticipant-drivenâ in one way or another. Participant-driven genomic research (PDGR) groups often work from âlabsâ that consist of servers and computing devices as much as wet lab apparatus, relying on information-processing software for data-driven, discovery-based analysis rather than hypothesis-driven experimentation. We interviewed individuals from a variety of efforts across the expanding ecosystem of PDGR, including academic groups, start-ups, activists, hobbyists, and hackers, in order to compare and contrast how they relate their stated objectives, practices, and political and moral stances to institutions of expert scientific knowledge production. Results reveal that these groups, despite their diversity, share commitments to promoting alternative modes of housing, conducting, and funding genomic research and, ultimately, sharing knowledge. In doing so, PDGR discourses challenge existing approaches to research governance as well, especially the regulation, ethics, and oversight of human genomic information management. Interestingly, the reaction of the traditional genomics research community to this revolutionary challenge has not been negative: in fact, the community seems to be embracing the ethos espoused by PDGR, at the highest levels of science policy. As conventional genomic research assimilates the ethos of PDGR, the movementâs âdemocratizingâ views on research governance are likely to become normalized as well, creating new tensions for science policy and research ethics
Overcoming Vulnerability in the Life Course - Reflections on a Research Program
This chapter reflects on the twelve-year Swiss research program, âOvercoming vulnerability: Life course perspectivesâ (LIVES). The authors are longstanding members of its scientific advisory committee. They highlight the programâs major accomplishments, identify key ingredients of the programâs success as well as some of its challenges, and raise promising avenues for future scholarship. Their insights will be of particular interest to those who wish to launch similar large-scale collaborative enterprises. LIVES has been a landmark project in advancing the conceptualization, measurement, and analysis of vulnerability over the life course. The foundation it has provided will direct the next era of scholarship toward even greater specificity: in understanding the conditions under which vulnerability matters, for whom, when, and how. In a process-oriented life-course perspective, vulnerability is not viewed as a persistent or permanent condition but rather as a dormant condition of the social actor, activated in particular situations and contexts
Measurement of photoemission and secondary emission from laboratory dust grains
The overall goal of this project is experimentally determine the emission properties of dust grains in order to provide theorists and modelers with an accurate data base to use in codes that predict the charging of grains in various plasma environments encountered in the magnetospheres of the planets. In general these modelers use values which have been measured on planar, bulk samples of the materials in question. The large enhancements expected due to the small size of grains can have a dramatic impact upon the predictions and the ultimate utility of these predictions. The first experimental measurement of energy resolved profiles of the secondary electron emission coefficient, 6, of sub-micron diameter particles has been accomplished. Bismuth particles in the size range of .022 to .165 micrometers were generated in a moderate pressure vacuum oven (average size is a function of oven temperature and pressure) and introduced into a high vacuum chamber where they interacted with a high energy electron beam (0.4 to 20 keV). Large enhancements in emission were observed with a peak value, delta(sub max) = 4. 5 measured for the ensemble of particles with a mean size of .022 micrometers. This is in contrast to the published value, delta(sub max) = 1.2, for bulk bismuth. The observed profiles are in general agreement with recent theoretical predictions made by Chow et al. at UCSD
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Flux: Insights into the Social Aspects of Life Transitions
Life transitions are often conceptualized and studied as individual experiences. But in reality, transitions are rarely individual: they are relational. We offer a set of insights into the social aspects of transitions. Transitions are experienced with and alongside others in states of interdependence. Family and other relationships can be key sources of support for transitions but also create risks. Changes in the transition patterns of cohorts are fertile ground for intergenerational tension in families and societies. Much of the action relevant to understanding life transitions is also found in the mind, in processes related to inequality, and in invisible forces related to history, demography, and institutions. Illustrations reinforce the principle that to understand the personal, we must look beyond the personal. Because transitions have strong social aspects, they can be strengthened through interventions, institutions, and policies
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Development of detection techniques and diagnostics for airborne carbon nanoparticles.
We have recorded time-resolved LII signals from a laminar ethylene diffusion flame over a wide range of laser fluences at 532 nm. We have performed these experiments using an injection-seeded NdYAG laser with a pulse duration of 7 ns. The beam was spatially filtered and imaged into the flame to provide a homogeneous spatial profile. These data were used to aid in the development of a model, which will be used to test the validity of the LII technique under varying environmental conditions. The new model describes the heating of soot particles during the laser pulse and the subsequent cooling of the particles by radiative emission, sublimation, and conduction. The model additionally includes particle heating by oxidation, accounts for the likelihood of particle annealing, and incorporates a mechanism for nonthermal photodesorption, which is required for good agreement with our experimental results. In order to investigate the fast photodesorption mechanism in more detail, we have recorded LII temporal profiles using a regeneratively amplified Nd:YAG laser with a pulse duration of 70 ps to heat the particles and a streak camera with a temporal resolution of {approx}65 ps to collect the signal. Preliminary results confirm earlier indications of a fast mechanism leading to signal decay rates of much less than a nanosecond. Parameters to which the model is sensitive include the initial soot temperature, the temperature of the ambient gas, and the partial pressure of oxygen. In order to narrow the model uncertainties, we have developed a source of soot that allows us to determine and control these parameters. Soot produced by a burner is extracted, diluted, and cooled in a flow tube, which is equipped with a Scanning Mobility Particle Sizer (SMPS) for characterization of the aggregates
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