Affordable Housing and Transportation Cost Burdens in San Diego County

The State of California has increasingly urged construction of affordable housing development in transit-rich areas (California Department of Housing and Community Development 2024) but so far transit-oriented development has generally not reduced vehicle miles traveled for low-income renters (Chatman et al. 2019; Lund, Cervero, and Willson 2004). This report quantifies the cost of daily travel needs for affordable housing residents in San Diego, California, especially seniors aged 62 and older, in two ways. First, it analyzes their trip travel time for the entire San Diego region using activity-based model (ABM) data. Second, it summarizes results from surveys of residents in six affordable housing buildings, three of which provide supportive housing to seniors. Overall, it finds that affordable housing residents use public transit more often than those who have access to a car. But traveling by public transit takes much longer on public transit than traveling by personal vehicle. Survey respondents under age 62 expressed greater dissatisfaction with the costs of public transit ridership, compared to seniors, and were also more likely to express dissatisfaction if they were working. Seniors were more likely to express dissatisfaction with the conditions of public transit stops

Stable isotope record, organic geochemistry and sea surface temperature estimation of ODP Hole 117-721B (Table 1)

Late Pleistocene sea surface water temperatures (SST) offshore Oman were calculated from the UK'37 ratio measured in sediment extracts from ODP holes drilled on the Oman Margin (723B, 728B) and on the Owen Ridge (721B, 731A). The data revealed a complex history of SST variations with a temperature range of 18°/19°C-27°/28°C, which is in accord with the present-day SST range in the western Arabian Sea. We found that, notably, in the glacial periods of isotopic stages 3 and 8 the SST was lower than during the interglacials. The lowest SST values occurred during isotopic stage 3. A mechanism involving a strong influence of cold northeasterly winds during glacial periods, with the southwestern monsoon being less effective at the same time, explains cold SST during glacial periods. However, further research is necessary to approve or disapprove this mechanism, because in the present study not all glacial periods were clearly marked by low SST values

(Table 1) Organic carbon and hydrogen index data for sediment samples from ODP Site 105-645

The extractable organic matter in Holocene to early Miocene deep-sea sediments from Site 645 (ODP Leg 105) in Baffin Bay contains almost exclusively biological markers of terrigenous origin. Pentacyclic triterpenoids of the alpha-(ursene) and beta-amyrin (oleanene) type often occur as the most abundant compounds in the aliphatic hydrocarbon, ketone and alcohol fractions of the sediment extract. A specific diagenetic reaction involves the conversion of taraxer-14-ene into olean-12-ene in the upper 700 metres of the sedimentary sequence. The taraxerene-to-oleanene conversion is complete before the onset of isomerisation of diasterenes at C-20. In the sediment as well as in laboratory simulation experiments, olean-12-ene further isomerises to olean-13(18)-ene and olean-18-ene, the latter of which may be the direct precursor of 18beta(H)- and 18alpha(H)-oleanane found in sediments containing more mature organic matter and in crude oils. The subsurface interconversion of these triterpenoid skeletons indicate that oleanane does not necessarily start life as an oleanoid

Organic carbon concentrations in ODP Hole 105-645E

The aliphatic hydrocarbon fractions of eight early Miocene to Pliocene sediment samples from Hole 645E (Baffin Bay; ODP Leg 105) were investigated by gas chromatography and gas chromatography/mass spectrometry. Long, straight-chain alkanes of terrigenous origin are often present as major compounds. Other terrigenous biological markers include three oleanenes with a double bond at positions 12, 13(18), or 18, and taraxer-14-ene. Urs-12-ene is identified tentatively. In the three deepest samples, 17a(H), 18a(H), and 210(H)-28, 30-bisnorhopane is the most abundant compound. Several new compounds were detected, some of which are tentatively identified. The identification and possible significance of 23-norlupane, three A/B-ring nuclear demethylated (or A-nor-) oleanenes, and an A/B-ring nuclear demethylated (or A-nor-) urs-12-ene are discussed. The authors postulate that taraxer-14-ene isomerizes to olean-12-ene with increasing burial depth

Lipid analyses of ODP Leg 117 samples

The solvent-extractable organic fractions of sediment samples from six Ocean Drilling Program Leg 117 sites were investigated by gas chromatography and gas chromatography-mass spectrometry. Sediments deposited in the Indus Fan (Site 720) as well as Miocene sediments from the Owen Ridge (Sites 722 and 731) contain almost exclusively organic matter of terrigenous origin. The organic matter in sediments from the Oman Margin (Sites 723, 725, and 728) and in the Pliocene/Pleistocene sections from the Owen Ridge is mainly of a marine origin with variable admixtures of terrigenous material. In these latter samples strong variations of the lipid composition and distribution are noted. However, the interpretation of the relation to potential biological sources is hampered by a lack of information on the possible lipid composition of appropriate organisms

Carbon chemistry of ODP Holes 108-658A and 108-659B (Table 1)

Preliminary results of lipid analyses of six samples from Site 658, underlying a present-day active upwelling cell, and of one sample from Site 659 are reported in this paper. Long-chain unsaturated ketones of prymnesiophyceae algae origin are the most abundant compounds in extracts from Site 658, followed by marine-derived steroids. n-Alkanes are of minor importance in these samples, but they predominate in the sample from Site 659. Our interpretation of the results indicates that organic-matter preservation was good to excellent at Site 658 and poor at Site 659, and that an analysis of only aliphatic hydrocarbons leads to an overestimation of the contribution of terrigenous organic matter at Site 658. Increased primary productivity, high sedimentation rates, and oxygen-depleted water masses associated with upwelling are thought to be the key factors for preservation. At the present stage of research, no specific biomarkers have been found that indicate upwelling