5,816 research outputs found

    Marriage Patterns in the United States

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    This paper analyzes cohort marriage patterns in the United States in order to determine whether declining rates of first marriage are due to changes in the timing of marriage, the incidence of marriage, or both. Parametric models, which are well-suited to the analysis of censored or truncated data, are fit separately to information on age at first marriage derived from three data sets which were collected independently and at different points in time. Extended versions of the models are also estimated in which the parameters of the model distributions are allowed to depend on social and, economic variables.The results provide evidence that the incidence of first marriage is declining and that there is only a slight tendency for women to delay marriage. In addition, education is the most important correlate of decisions about the timing of first marriage whereas race is the most important correlate of decisions about its incidence.

    Commitment and the Modern Union: Assessing the Link Between Premarital Cohabitation and Subsequent Marital Stability

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    In recent years, the incidence of premarital cohabitation has increased dramatically in many countries of Western Europe and in the United States. As cohabitation becomes a more common experience, it is increasingly important to understand the links between cohabitation and other steps in the process of family formation and dissolution. We focus on the relationship between pre- marital cohabitation and subsequent marital stability, and analyze data from the 1981 Women in Sweden survey using a hazards model approach. Our results indicate that women who premaritally cohabit have almost 80 percent higher marital dissolution rates than those who do not cohabit. Women who cohabit for over three years prior to marriage have over 50 percent higher dissolution rates than women who cohabit for shorter durations. Last, cohabitors and non-cohabitors whose marriages have remained intact for eight years appear to have identical dissolution rates after that time. In addition, we provide evidence that strongly suggests a weaker commitment, on the part of those who cohabit premaritally, to the institution of marriage.

    ECOLOGICAL-ECONOMIC MODELING ON A WATERSHED BASIS: A CASE STUDY OF THE CACHE RIVER OF SOUTHERN ILLINOIS

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    A digitally represented watershed landscape (ARC/INFO GIS) is merged with farm optimization (linear programming) and sediment and chemical transport (AGNPS) models. Enhanced targeting of non-point source pollution to remedial policy and management initiatives result. The implications of which are linked back to farm income and forward to the managed ecosystem.Environmental Economics and Policy, Research and Development/Tech Change/Emerging Technologies,

    Match Probability Statistics and Gamma Ray Burst Recurrences in the BATSE Catalog

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    We develop match probability statistics to test the recurrences of gamma ray bursts in the BATSE catalog 1B and 2B. We do not find a signal of repetitions at the match level of 1.e-3.Comment: 4 pages, LaTeX, two macros included (kluwer.sty, spacekap.sty) To appear in the proceedings of the Eslab29 symposium, ``gamma ray bursts: toward the source

    Spectral Type and Radial Velocity Variations in Three SRC Variables

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    SRC variables are M supergiants, precursors to Type II supernovae, that vary in brightness with moderately regular periods of order 100-1000 days. Although identified as pulsating stars that obey their own period-luminosity relation, few have been examined in enough detail to follow the temperature and spectral changes that they undergo during their long cycles. The present study examines such changes for several SRC variables revealed by CCD spectra obtained at the Dominion Astrophysical Observatory (DAO) during 2005-2009, as well as by archival spectra from the DAO (and elsewhere) for some stars from the 1960s to 1980s, and Cambridge radial velocity spectrometer measures for Betelgeuse. Described here is our classification procedure and information on the spectral type and radial velocity changes in three of the stars. The results provide insights into the pulsation mechanism in M supergiants.Comment: To appear in the Odessa Variable Stars 2010 conference proceedings (see http://uavso.org.ua/?page=vs2010), edited by I. Andronov and V. Kovtyuk

    Acute reduction of microglia does not alter axonal injury in a mouse model of repetitive concussive traumatic brain injury

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    The pathological processes that lead to long-term consequences of multiple concussions are unclear. Primary mechanical damage to axons during concussion is likely to contribute to dysfunction. Secondary damage has been hypothesized to be induced or exacerbated by inflammation. The main inflammatory cells in the brain are microglia, a type of macrophage. This research sought to determine the contribution of microglia to axon degeneration after repetitive closed-skull traumatic brain injury (rcTBI) using CD11b-TK (thymidine kinase) mice, a valganciclovir-inducible model of macrophage depletion. Low-dose (1 mg/mL) valganciclovir was found to reduce the microglial population in the corpus callosum and external capsule by 35% after rcTBI in CD11b-TK mice. At both acute (7 days) and subacute (21 days) time points after rcTBI, reduction of the microglial population did not alter the extent of axon injury as visualized by silver staining. Further reduction of the microglial population by 56%, using an intermediate dose (10 mg/mL), also did not alter the extent of silver staining, amyloid precursor protein accumulation, neurofilament labeling, or axon injury evident by electron microscopy at 7 days postinjury. Longer treatment of CD11b-TK mice with intermediate dose and treatment for 14 days with high-dose (50 mg/mL) valganciclovir were both found to be toxic in this injury model. Altogether, these data are most consistent with the idea that microglia do not contribute to acute axon degeneration after multiple concussive injuries. The possibility of longer-term effects on axon structure or function cannot be ruled out. Nonetheless, alternative strategies directly targeting injury to axons may be a more beneficial approach to concussion treatment than targeting secondary processes of microglial-driven inflammation

    Hexagonal ABCABC as semiconducting ferroelectrics

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    We use a first-principles rational-design approach to identify a previously-unrecognized class of ferroelectric materials in the P63mcP63mc LiGaGe structure type. We calculate structural parameters, polarization and ferroelectric well depths both for reported and as-yet hypothetical representatives of this class. Our results provide guidance for the experimental realization and further investigation of high-performance materials suitable for practical applications.Comment: 5 pages, 2 figures, 3 table

    Patient Evaluation of Emotional Comfort Experienced (PEECE): Developing and testing a measurement instrument

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    Objectives: The Patient Evaluation of Emotional Comfort Experienced (PEECE) is a 12-item questionnaire which measures the mental well-being state of emotional comfort in patients. The instrument was developed using previous qualitative work and published literature. Design: Instrument development. Setting: Acute Care Public Hospital, Western Australia. Participants: Sample of 374 patients. Interventions: A multidisciplinary expert panel assessed the face and content validity of the instrument and following a pilot study, the psychometric properties of the instrument were explored. Main outcome measures: Exploratory and confirmatory factor analysis assessed the underlying dimensions of the PEECE instrument; Cronbach’s α was used to determine the reliability; κ was used for test–retest reliability of the ordinal items. Results: 2 factors were identified in the instrument and named ‘positive emotions’ and ‘perceived meaning’. A greater proportion of male patients were found to report positive emotions compared with female patients. The instrument was found to be feasible, reliable and valid for use with inpatients and outpatients. Conclusions: PEECE was found to be a feasible instrument for use with inpatient and outpatients, being easily understood and completed

    Modeling American Marriage Patterns

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