253 research outputs found

    Advancing Understanding of Long-Distance and Intercity Travel with Diverse Data Sources

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    Long-distance travel is an ambiguous designation that is used to refer to an extremely diverse set of trips, differing from one another in mode, distance, and purpose. Long-distance travel encompasses everything from short long-distance surface trips between adjacent metropolitan areas through intercontinental air trips spanning thousands of miles. These trips serve a wide range of purposes including business travel, leisure travel, and travel to access essential services such as medical care. As such, long-distance travel is increasingly important for sustainable transportation planning both due to the environmental externalities associated with these trips and also because the benefits of access to long-distance travel are inequitably distributed throughout the population. This project drew on five survey datasets, a mobiledevice based dataset from AirSage Inc., and semi-structured interviews to address research questions related to how best to measure long-distance travel, how long-distance travel influences well-being, and how access to long-distance travel varies among socio-demographic groups. Adequately defining long-distance travel for data collection and modeling remains a challenge and long-distance travel behavior researchers are continuing to experiment with innovative data collection methods for measuring these trips. It is clear that the most common current long-distance data collection methods are suboptimal. Distance thresholds, such as trips over 50 or 75 miles, are a poor method for defining long-distance travel on a national or global scale and there is no consensus on the appropriate recall period for retrospective long-distance travel surveys. Several promising avenues for future research and data collection were identified through this project. Focusing on more memorable long-distance travel indicators within surveys, such as overnight trips, trips including air travel, or an individual\u27s maximum distance from home, may reduce recall error and provide useful outcome measures for assessing individuals\u27 overall long-distance travel tendencies. Project results indicated that expanded use of convenience samples may provide more cost-effective opportunities to measure long-distance trip length and destination distributions. Social network characteristics may be predictive of certain types of long-distance travel and additional methodological improvements are needed to understand how to more effectively collect social network information including network geography. Analysis of survey data in this project suggested that one-time, self-assessed travel frequency estimates (a common existing measure of longdistance travel) can provide only a crude approximation of the levels of long-distance travel and that self-assessment is most effective for identifying non-travelers and very infrequent travelers. Historically, transportation equity research has focused on access to local goods and services but access to long-distance travel and to more distant destinations is increasingly important for maintaining social networks and accessing economic opportunities and specialized services. Across multiple datasets in this project, there is ample evidence that lower-income individuals engage in less long-distance travel and have more unmet long-distance travel needs than their higher-income counterparts. Given both the theoretical and empirical evidence that longdistance and intercity travel is correlated with an individuals’ own sense of well-being, especially for leisure or personal purposes, inequitable access to long-distance travel cannot be ignored. This finding suggests generally that lack of equity in long-distance access has been masked by lack of data and is a policy concern that must be considered in sustainable transportation planning moving forward

    Oldest Skeleton of a Plesiadapiform provides additional evidence for an exclusively arboreal radiation of stem Primates in the Palaeocene

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    Palaechthonid plesiadapiforms from the Palaeocene of western North America have long been recognized as among the oldest and most primitive euarchontan mammals, a group that includes extant primates, colugos and treeshrews. Despite their relatively sparse fossil record, palaechthonids have played an important role in discussions surrounding adaptive scenarios for primate origins for nearly a half-century. Likewise, palaechthonids have been considered important for understanding relationships among plesiadapiforms, with members of the group proposed as plausible ancestors of Paromomyidae and Microsyopidae. Here, we describe a dentally associated partial skeleton of Torrejonia wilsoni from the early Palaeocene (approx. 62Ma) of New Mexico, which is the oldest known plesiadapiform skeleton and the first Palaechthonid plesiadapiforms from the Palaeocene of western North America have long been recognized as among the oldest and most primitive euarchontan mammals, a group that includes extant primates, colugos and treeshrews. Despite their relatively sparse fossil record, palaechthonids have played an important role in discussions surrounding adaptive scenarios for primate origins for nearly a half-century. Likewise, palaechthonids have been considered important for understanding relationships among plesiadapiforms, with members of the group proposed as plausible ancestors of Paromomyidae and Microsyopidae. Here, we describe a dentally associated partial skeleton of Torrejonia wilsoni from the early Palaeocene (approx. 62Ma) of New Mexico, which is the oldest known plesiadapiform skeleton and the firs

    Ecological selectivity and the evolution of mammalian substrate preference across the K-Pg boundary.

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    The Cretaceous-Paleogene (K-Pg) mass extinction 66 million years ago was characterized by a worldwide ecological catastrophe and rapid species turnover. Large-scale devastation of forested environments resulting from the Chicxulub asteroid impact likely influenced the evolutionary trajectories of multiple clades in terrestrial environments, and it has been hypothesized to have biased survivorship in favour of nonarboreal lineages across the K-Pg boundary. Here, we evaluate patterns of substrate preferences across the K-Pg boundary among crown group mammals, a group that underwent rapid diversification following the mass extinction. Using Bayesian, likelihood, and parsimony reconstructions, we identify patterns of mammalian ecological selectivity that are broadly similar to those previously hypothesized for birds. Models based on extant taxa indicate predominant K-Pg survivorship among semi- or nonarboreal taxa, followed by numerous independent transitions to arboreality in the early Cenozoic. However, contrary to the predominant signal, some or all members of total-clade Euarchonta (Primates + Dermoptera + Scandentia) appear to have maintained arboreal habits across the K-Pg boundary, suggesting ecological flexibility during an interval of global habitat instability. We further observe a pronounced shift in character state transitions away from plesiomorphic arboreality associated with the K-Pg transition. Our findings are consistent with the hypothesis that predominantly nonarboreal taxa preferentially survived the end-Cretaceous mass extinction, and emphasize the pivotal influence of the K-Pg transition in shaping the early evolutionary trajectories of extant terrestrial vertebrates.NS

    Lability of Pb in soil: effects of soil properties and contaminant source

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    Environmental Context: There is growing concern that lead (Pb) in the environment may cause adverse health effects in human populations. We investigated the combined use of isotopic abundance and isotopic dilution to show how the origins of soil Pb and soil characteristics affect lability. Soil pH and soil Pb content are the dominant controls on Pb lability; the lability of recent petrol-derived Pb is similar to that of other sources in urban soils but greater than geogenic Pb in rural roadside topsoils. Lability of lead (Pb) in soils is influenced by both soil properties and source(s) of contamination. We investigated factors controlling Pb lability in soils from (i) land adjacent to a major rural road, (ii) a sewage processing farm and (iii) an archive of the geochemical survey of London. We measured isotopically exchangeable Pb (E-values; PbE), phase fractionation of Pb by a sequential extraction procedure (SEP) and inferred source apportionment from measured Pb isotopic ratios. Isotopic ratios (206Pb/207Pb and 208Pb/207Pb) of total soil Pb fell on a mixing line between those of petrol and UK coal or Pb ore. The main determinant of the isotopically exchangeable Pb fraction (%E-value) was soil pH: %E-values decreased with increasing pH. In rural roadside topsoils and there was also evidence that, petrol-derived Pb remained more labile (35%) than Pb from soil parent material (27%). However, in biosolid-amended and London soils %E-values were low (c. 25%), covered a restricted range, and showed no clear evidence of source-dependent lability

    A Simple and Robust Single-Step Method for CAR-Vδ1 γδT Cell Expansion and Transduction for Cancer Immunotherapy

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    The γδT cell subset of peripheral lymphocytes exhibits potent cancer antigen recognition independent of classical peptide MHC complexes, making it an attractive candidate for allogeneic cancer adoptive immunotherapy. The Vδ1-T cell receptor (TCR)-expressing subset of peripheral γδT cells has remained enigmatic compared to its more prevalent Vγ9Vδ2-TCR and αβ-TCR-expressing counterparts. It took until 2021 before a first patient was dosed with an allogeneic adoptive Vδ1 cell product despite pre-clinical promise for oncology indications stretching back to the 1980s. A contributing factor to the paucity of clinical progress with Vδ1 cells is the lack of robust, consistent and GMP-compatible expansion protocols. Herein we describe a reproducible one-step, clinically translatable protocol for Vδ1-γδT cell expansion from peripheral blood mononuclear cells (PBMCs), that is further compatible with high-efficiency gene engineering for immunotherapy purposes. Briefly, αβTCR- and CD56-depleted PBMC stimulation with known-in-the-art T cell stimulators, anti-CD3 mAb (clone: OKT-3) and IL-15, leads to robust Vδ1 cell expansion of high purity and innate-like anti-tumor efficacy. These Vδ1 cells can be virally transduced to express chimeric antigen receptors (CARs) using standard techniques, and the CAR-Vδ1 exhibit antigen-specific persistence, cytotoxicity and produce IFN-γ. Practicable, GMP-compatible engineered Vδ1 cell expansion methods will be crucial to the wide-spread clinical testing of these cells for oncology indications

    Flight Testing of Nap of-the-Earth Unmanned Helicopter Systems

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    This paper describes recent results from a partnership between the Sikorsky Aircraft Corporation and the Georgia Institute of Technology to develop, improve, and flight test a sensor, guidance, navigation, control, and real-time flight path optimization system to support high performance nap-of-the-Earth helicopter flight. The emphasis here is on optimization for a combination of low height above terrain/obstacles and high speeds. Multiple methods for generating the desired flight path were evaluated, including (1) a simple processing of each laser scan; and (2) a potential field based method. Simulation and flight test results have been obtained utilizing an onboard laser scanner to detect terrain and obstacles while flying at low altitude, and have successfully demonstrated obstacle avoidance in a realistic semi-urban environment at speeds up to 40 ft/s while maintaining a miss distance of 50 ft horizontally and vertically. These results indicate that the technical approach is sound, paving the way for testing of even lower altitudes, higher speeds, and more aggressive maneuvering in future work

    Accelerated BEP : a phase I trial of dose-dense BEP for intermediate and poor prognosis metastatic germ cell tumour

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    Background: We used bleomycin, etoposide, cisplatin (BEP), the most effective regimen in the treatment of germ cell tumours (GCTs) and increased dose-density by using pegfilgrastim to shorten cycle length. Our aim was to assess safety and tolerability. Methods: Sixteen male patients with intermediate or poor prognosis metastatic GCT were treated with four cycles of 3-day BEP with G-CSF on a 14-day cycle for a planned relative dose-density of 1.5 compared with standard BEP. Results: Eleven intermediate and five poor prognosis patients were treated. In all, 14 of 16 patients completed the study treatment. Toxicities were comparable to previous studies using standard BEP, except for mucositis and haematological toxicity that were more severe. The overall relative dose-density for all 16 patients was mean 1.38 (range 0.72–1.5; median 1.46). Complete response was achieved after chemotherapy alone in two patients (13%) and following chemotherapy plus surgery in nine additional patients (56%). Four patients (25%) had a partial response and normalised their marker levels. At a median follow-up of 4.4 years (range 2.1–6.8) the estimated 5-year progression-free survival probability is 81% (95% CI 64–100%). Conclusion: Accelerated BEP is tolerable without major additional toxicity. A randomised controlled trial will be required to obtain comparative efficacy data
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