1,377 research outputs found

    A common trajectory recapitulated by urban economies

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    Is there a general economic pathway recapitulated by individual cities over and over? Identifying such evolution structure, if any, would inform models for the assessment, maintenance, and forecasting of urban sustainability and economic success as a quantitative baseline. This premise seems to contradict the existing body of empirical evidences for path-dependent growth shaping the unique history of individual cities. And yet, recent empirical evidences and theoretical models have amounted to the universal patterns, mostly size-dependent, thereby expressing many of urban quantities as a set of simple scaling laws. Here, we provide a mathematical framework to integrate repeated cross-sectional data, each of which freezes in time dimension, into a frame of reference for longitudinal evolution of individual cities in time. Using data of over 100 millions employment in thousand business categories between 1998 and 2013, we decompose each city's evolution into a pre-factor and relative changes to eliminate national and global effects. In this way, we show the longitudinal dynamics of individual cities recapitulate the observed cross-sectional regularity. Larger cities are not only scaled-up versions of their smaller peers but also of their past. In addition, our model shows that both specialization and diversification are attributed to the distribution of industry's scaling exponents, resulting a critical population of 1.2 million at which a city makes an industrial transition into innovative economies

    relationship between the level of local participation and the effectiveness of the agricultural projects

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    Thesis(Master) --KDI School:Master of Public Policy,2013masterpublishedHyejin Jung

    Is neighborhood poverty harmful to every child? Neighborhood poverty, family poverty, and behavioral problems among young children

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    This longitudinal study investigates the association between neighborhood poverty and behavioral problems among young children. This study also examines whether social environments mediate the relationship between neighborhood poverty and behavioral problems. We used data from the third and fourth waves of the Fragile Families and Child Wellbeing study to assess behavioral problems separately for children who experienced no family poverty, moved out of family poverty, moved into family poverty, and experienced long‐term family poverty. Regression models assessed the effect of neighborhood poverty on behavioral problem outcomes among children aged 5 years, after controlling for sociodemographic characteristics and earlier behavioral problems. Results showed an association between neighborhood poverty and lower social cohesion and safety, which lead to greater externalizing problems among children with long‐term family poverty living in high‐poverty neighborhoods compared with those in low‐poverty neighborhoods. Policies and community resources need to be allocated to improve neighborhood social environments, particularly for poor children in high‐poverty neighborhoods.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148233/1/jcop22140.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148233/2/jcop22140_am.pd

    Validation of the Korean Version of the Community Assessment of Psychic Experiences in General Population

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    OBJECTIVE: The Community Assessment of Psychic Experiences has been widely translated and commonly used as a measure for psychotic experiences and psychosis proneness in clinical and research environments worldwide. This study aimed to establish the psychometric properties (reliability and validity) and factor structure of a Korean version of the Community Assessment of Psychic Experiences (K-CAPE) in the general population. METHODS: A total of 1,467 healthy participants completed K-CAPE and other psychiatric symptom-related scales (Paranoia scale, Patient Health Questionnaire-9, Dissociative Experiences Scale-II, and Oxford-Liverpool Inventory of Feelings and Experiences) via online survey. K-CAPE's internal reliability was analyzed using Cronbach's alpha coefficient. Confirmatory factor analysis (CFA) was performed to investigate whether the original three-factor model (positive, negative, and depressive) and other hypothesized multidimensional models (including positive and negative subfactors) were suitable for our data. Exploratory factor analysis (EFA) was conducted to explore better alternative factor solutions with a follow-up CFA. To assess convergent and discriminant validity, we examined correlations between KCAPE subscales with other established measures of psychiatric symptoms. RESULTS: K-CAPE showed good internal consistency in all original three subscales (all greater than α=0.827). The CFA demonstrated that the multidimensional models exhibited relatively better quality than the original three-dimensional model. Although the model fit indices did not reach their respective optimal thresholds, they were within an acceptable range. Results from the EFA indicated 3-5 factor solutions. In 3-factor solution, "negative-avolition" items were founded to be loaded more consistently with depressive items than with the negative dimension. In 4-factor solution, positive items were divided into two subfactors: "positive-bizarre experiences" and "positive-delusional thoughts," while negative symptoms were separated into two distinct subfactors in 5-factor solution: "negative-avolition (expressive)," and "negative-social (experiential)." The correlation coefficients between K-CAPE subscales and corresponding measurements were significant (p<0.001), confirming the convergent and discriminant validity. CONCLUSION: Our study provides evidence to support the reliability and validity of the K-CAPE and its use as a measure of psychotic symptoms in the Korean population. Although alternative factor structures did not improve the model fit, our EFA findings implicate the use of subfactors to investigate more specific domains of positive and negative symptoms. Given the heterogeneous nature of psychotic symptoms, this may be useful in capturing their different underlying mechanisms

    Quetiapine Misuse and Abuse: Is It an Atypical Paradigm of Drug Seeking Behavior?

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    Recent case reports in medical literatures suggest that more and more second-generation atypical antipsychotics (AAs) have been prescribed for off-label use; quetiapine (Brand name: Seroquel®) showed increase in its trend for off-label use. Little is known about the reasons behind this trend, although historical sedative and hypnotic prescription patterns suggest that despite relatively superior safety profiles of quetiapine (especially for movement disorders), it may be used for treating substance abuse disorder. In addition, recent studies have shown a strong potential for misuse and abuse (MUA) of quetiapine beyond Food and Drug Administration-approved indications. This includes drug-seeking behaviors, such as feigning symptoms, motivated by quetiapine and use of quetiapine in conjunction with alcohol. Quetiapine appears to be the most documented AA with street values bartered illicitly on the street. A recent report from the Drug Abuse Warning Network has shown a high prevalence of quetiapine-related emergency department visits involving MUA. Several other case studies have found that quetiapine causes seeking behaviors observed in substance use disorder. In fact, the majority of quetiapine MUA involved patients diagnosed with substance use disorder. In the absence of a definitive mechanism of action of quetiapine\u27s reinforcing properties, it is imperative to gather robust evidence to support or refute increasing off-label use of AAs

    Experimental investigation of plain- and flapped-wing tip vortices

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    Particle image velocimetry was used in a low-speed wind tunnel to investigate and characterize wing tip vortex structures. A rectangular wing of a subsonic wall interference model was used as a vortex generator in two different configurations: 1) plain wing and 2) flapped wing with the trailing-edge flap extended at 20 degrees. Vortex flow quantities and their dependence on angle of attack at Reynolds numbers of 32:8 � 103 and 43:8 � 103 were evaluated. Assessment of measured data reveals that the peak values of tangential velocities, vortex strength, and vorticities are directly proportional to the angle of attack. The vortex core radius value grows slowly as the angle of attack is increased. Both plain and flapped configurations showed similar trends. The peak tangential velocities and circulation almost doubled when the flapped configuration was used instead of the plain wing

    Experimental investigation of wing tip vortex

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    Particle image velocimetery was used in a low-speed wind tunnel to investigate and characterize wing tip vortex structures. A rectangular wing of a SWIM model was used as a vortex generator in two different configurations, (i) plain wing and (ii) flapped wing with trailing edge flap extended at 20 degrees. Vortex flow quantities and their dependence on angle of attack at a chord base Reynolds Number of 32.8x103 and 43.8x103 were evaluated. Assessment of measured data reveals that the peak values of tangential velocities, vortex strength and vorticities are directly proportional to the angle of attack. The vortex core radius value grows slowly as the angle of attack is increased. Both plain and flapped configurations showed similar trends. The peak tangential velocities and circulation distribution doubled when the flapped configuration was used instead of the plain wing
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