Residential Location Choice and Travel Behavior of Young adults: Coming-to-the-city and Multimodality

Young adults have received increasing attention since the late 2000s due to their different residential choice and travel behavior when compared to prior generations and older cohorts. Young adults drove fewer miles, owned fewer cars, and used non-automobile modes (public transit, walk, or bicycle modes) at a higher rate. Further, young adults showed a higher preference for living in cities. A higher proportion of young adults lived in central areas in cities in the 2010s than the 2000s and as compared to other age groups. This dissertation examines these two choice behaviors of young adults to fill gaps in literature through three independent research. The first research examines residential location trends of young adults and older adults in the most populous 50 U.S. cities and important factors in their decisions. The second research examines differences in residential location choice within young adults using national-level longitudinal data. Last, the research examines the relationship between location choice and travel behavior using travel survey data in the Seattle metropolitan area. The main findings from the dissertation can be summarized as follows: 1) Young adults have come to U.S. cities since 2000 and at higher rate since 2010, while older age groups have left cities. Urban industry (especially high-income jobs), transportation, and amenities are important factors in the location preference of young adults. 2) There is also a diversity in residential location preference within the young adult cohort that depends on their lifecycle stage and socio-demographic characteristics as well as a period (the 2000s vs. 2010s). 3) There are complex relationships between being a young adult, location choice, and travel behavior. One of the findings is that being a young adult has no direct effects on mode choice and travel distance. Its effects are only indirect through the residential location and auto ownership decisions. Taken together, these findings suggest that if conditions in cities don’t change in ways that make them attractive to the life cycle of young adults, it is very likely that their behaviors will become like that of prior generations —suburbs, more cars, and more driving. Young adults, however, are showing interests in living in cities, it is a role of planners and policy makers to encourage them to stay as they age and to attract even more of them

Dinuclear gold(I) pseudohalogen complexes bridged by a ferrocenyl bisphosphine ligand: synthesis, structure, and reactivity toward isothiocyanate

Ferrocenyl bisphosphine-bridged dinuclear gold(I) complexes containing CF3COO as a pseudohalogen ligand were synthesized from the corresponding halides using CF3COOAg. The sequential treatment of gold(I) trifluoroacetates with aqueous NaN3 afforded the corresponding ferrocenyl bisphosphine-bridged dinuclear gold(I) azides. Isolated gold(I) pseudohalogen complexes were characterized through IR, NMR and X-ray crystallography. The characteristic IR absorption bands of ν(CO), ν(CF), and ν(N3) were at 1690, 1190, and 2040 cm−1, respectively, corresponding to the gold(I) trifluoroacetates and azides, verifying gold(I) pseudohalogen formation. The molecular structure of [Au2(η1-CF3CO2)2(µ-dippf)] (dippf = 1,1’-bis(diisopropylphosphino)ferrocene) through X-ray diffraction showed intermolecular Au⋅⋅⋅Au interactions with close contacts between molecules. The crystallographic images illustrate the polymeric chain of bis(phosphino)ferrocenyl gold(I) formed via intermolecular Au⋅⋅⋅Au bonds and layered packing arrays. In contrast, the molecular structures of [Au2(η1-CF3CO2)2(µ-dtbpf)] (dtbpf = 1,1’-bis(di-tert-butylphosphino)ferrocene) and Au2(N3)2(µ-dippf) showed intramolecular Au⋅⋅⋅Au aurophilic interactions, but the structures of [Au2(η1-CF3CO2)2(µ-dcpf)] (dcpf = 1,1′-bis(dicyclohexylphosphino)ferrocene) and Au2(N3)2(µ-dppf) revealed no direct interaction within the dinuclear gold(I) system. Gold(I) azides gradually react with isothiocyanates (allyl, (S)-(+)-1-phenylethyl, and benzyl) to afford the corresponding gold(I) tetrazole-thiolates [Au2X2(µ-dippf)] or [Au2X2(µ-dtbpf)] (X = S[CN4(Y)]) (Y = allyl, (S)-(+)-1-phenylethyl, and benzyl) via dipolar cycloaddition of the isothiocyanates into the Au-N3 bond.</p

Additional file 1: Table S1. of The impact of sitting time and physical activity on major depressive disorder in South Korean adults: a cross-sectional study

Men and women participants’ general characteristics. * Number of chronic diseases: Hypertension, dyslipidemia, stroke, myocardial infarction, angina, arthritis, rheumatoid arthritis, asthma, thyroid gland disorder, chronic renal failure, hepatitis B. * Number of chronic diseases: Hypertension, dyslipidemia, stroke, myocardial infarction, angina, arthritis, rheumatoid arthritis, asthma, thyroid gland disorder, chronic renal failure, hepatitis B. Table S2. Subgroup analysis of sitting-time and major depressive disorder according to physical activity. Adjusted for age, household income level, educational level, marital status, occupation, obesity, current smoking status, alcohol use and number of chronic diseases. (DOCX 51 kb

Additional file 1: Table S1. of The association between socioeconomic status and visual impairments among primary glaucoma: the results from Nationwide Korean National Health Insurance Cohort from 2004 to 2013

Multinomial logistic regression analysis under full model. The adjusted odds ratio using multinomial logistic regression under full model in consideration of variance inflation. (DOCX 18 kb

Additional file 1: of The cross-interaction between global and age-comparative self-rated health on depressive symptoms–considering both the individual and combined effects

Figure S1. Combined variables between global self-rated health (SRH-global) and age-comparative self-rated health (SRH-age). (JPG 56 kb

Additional file 4: of The cross-interaction between global and age-comparative self-rated health on depressive symptoms–considering both the individual and combined effects

Table S1. The association between covariates and SRHs. SRH means self-rated health. SRH-global is general self rated health, while SRH-age is age-comparative self–rated health. Chi-square tests were performed for statistical tests. (21 kb

Additional file 2: of The cross-interaction between global and age-comparative self-rated health on depressive symptoms–considering both the individual and combined effects

Figure S2. CESD by SRH-global and SRH-age separately, according to the quartile income group. SRH means self-rated health. SRH-global is general self rated health, while SRH-age is age-comparative self –rated health. The vertical axis means the estimates of CESD and the horizontal one is four income categories from low to high group. * p < 0.05 **p < 0.001. (JPG 80 kb

Additional file 3: of The cross-interaction between global and age-comparative self-rated health on depressive symptoms–considering both the individual and combined effects

Figure S3. Values of estimates for CES-D by each nine SRH-combined categories by gender. SRH means self-rated health. SRH-global is general self rated health, while SRH-age is age-comparative self–rated health. Among men, subjects with low SRH-age and all kinds of SRH-global levels (low; b = 0.825, p < 0.001, middle; b = 0.472, p = 0.006, high; b = 0.696, p = 0.001) had higher CESD compared to the reference middle SRH-global * middle SRH-age group. Similarly, women with low SRH-global * low SRH-age (b = 0.553, p < 0.001) and middle SRH-global * low SRH-age (b = 0.286, p = 0.037) showed association with higher CESD. However, there was no statistical difference in women with high SRH-global * low SRH-age group although the estimate was positive (b = 0.377, p = 0.064). (DOCX 18 kb

Ultrafast Energy Transfer Process in Confined Gold Nanospheres Revealed by Femtosecond X‑ray Imaging and Diffraction

Femtosecond laser pulses drive nonequilibrium phase transitions via reaction paths hidden in thermal equilibrium. This stimulates interest to understand photoinduced ultrafast melting processes, which remains incomplete due to challenges in resolving accompanied kinetics at the relevant space–time resolution. Here, by newly establishing a multiplexing femtosecond X-ray probe, we have successfully revealed ultrafast energy transfer processes in confined Au nanospheres. Real-time images of electron density distributions with the corresponding lattice structures elucidate that the energy transfer begins with subpicosecond melting at the specimen boundary earlier than the lattice thermalization, and proceeds by forming voids. Two temperature molecular dynamics simulations uncovered the presence of both heterogeneous melting with the melting front propagation from surface and grain boundaries and homogeneous melting with random melting seeds and nanoscale voids. Supported by experimental and theoretical results, we provide a comprehensive atomic-scale picture that accounts for the ultrafast laser-induced melting and evaporation kinetics

Ultrafast Energy Transfer Process in Confined Gold Nanospheres Revealed by Femtosecond X‑ray Imaging and Diffraction

Femtosecond laser pulses drive nonequilibrium phase transitions via reaction paths hidden in thermal equilibrium. This stimulates interest to understand photoinduced ultrafast melting processes, which remains incomplete due to challenges in resolving accompanied kinetics at the relevant space–time resolution. Here, by newly establishing a multiplexing femtosecond X-ray probe, we have successfully revealed ultrafast energy transfer processes in confined Au nanospheres. Real-time images of electron density distributions with the corresponding lattice structures elucidate that the energy transfer begins with subpicosecond melting at the specimen boundary earlier than the lattice thermalization, and proceeds by forming voids. Two temperature molecular dynamics simulations uncovered the presence of both heterogeneous melting with the melting front propagation from surface and grain boundaries and homogeneous melting with random melting seeds and nanoscale voids. Supported by experimental and theoretical results, we provide a comprehensive atomic-scale picture that accounts for the ultrafast laser-induced melting and evaporation kinetics