Understanding the Accessibility, Economic and Social Equity Impacts of Urban Greenway Infrastructure

“City Greenways” is a concept proposed as a part of Portland’s 2035 Comprehensive Plan, which calls for a citywide network of park-like pedestrian and bicycle friendly streets crisscrossing the city at roughly three-mile intervals. This research establishes several approaches to measure the transportation network impact of the “City Greenways” and relate bicycle network measures to economic and social equity outcomes. Expanding upon existing literature, we derived three sets of bicycle accessibility measures (BAMs). They are distance-based BAM, destinationbased BAM, and low-stress network-based BAM, which incorporate different components of a comprehensive bicycle network. The distancebased BAM measures accessibility of the active transportation infrastructure via a proximity measurement; the destination-based BAM measures the ease of access to the closest five important employment, retail, service and parks/recreation destinations; and the low-stress network-based BAM measures the comfort levels and willingness to use active transportation modes as a travel option, incorporating bicycle level of stress factors to determine the overall accessibility of the urban greenway network. The three sets of defined BAMs were applied to Portland’s current (2016) and proposed 2035 scenarios. We found that after the implementation of Portland’s “City Greenway” network, all three sets of BAMs showed improvements in accessibility compared to the existing network, although at varying degrees. The improved urban greenway network not only decreased the travel costs of active transportation due to well-connected network and higher comfort and safety levels of cycling, it would also provide increased accessibility to important destinations at lower stress levels within the same distances. Next, we explored the relationship between the bicycle accessibility levels of the urban greenway network and economic indicators. We found positive correlations between two BAMs (distance-based BAM and low-stress network-based BAM) with the number of jobs that are located in each census block. The low-stress network based proximity BAM appears to be the more preferred measure, due to the statistically significant correlations that we found. In addition, the hedonic price model indicated that higher BAM scores were associated with higher property values, particularly for multi-family homes. In general, better BAMs were associated with higher levels of economic activities. The spatial equity analysis examined the how bicycle accessibility is distributed across the metropolitan area and amongst identified historically marginalized communities (including communities with higher populations of people of color, low-income, limited English proficiency, older adults and younger persons), and how the proposed 2035 City Greenways plan might impact these communities differently. We found that the 2035 City Greenways plan, as measured through BAM slightly favor the disadvantaged population. While the distance-based BAM showed significant improvements in accessibility for many of the transportation-disadvantaged communities, the low-stress network-based BAMs showed tempered improvement in these communities. These results indicated that while residents might be better able to access the urban greenway network as more bicycle infrastructure was built, it did not necessarily translate into better access to important destinations without complementary economic development and land use policies expansion along the transportation infrastructure. It also underscores the importance of complementary economic development and land use policies that expand the spatial distribution of important destinations while investing in urban greenway infrastructure or other transportation network improvements

Urban Greenway Infrastructure: Economic and Social Impacts

“City Greenways” is a concept proposed as a part of Portland’s 2035 Comprehensive Plan, which calls for a citywide network of park-like pedestrian and bicycle friendly streets crisscrossing the city at roughly three-mile intervals. This research establishes several approaches to measure the transportation network impact of the “City Greenways” and relate bicycle network measures to economic and social equity outcomes. Expanding upon existing literature, we derived three sets of bicycle accessibility measures (BAMs). They are distance-based BAM, destinationbased BAM, and low-stress network-based BAM, which incorporate different components of a comprehensive bicycle network. The distancebased BAM measures accessibility of the active transportation infrastructure via a proximity measurement; the destination-based BAM measures the ease of access to the closest five important employment, retail, service and parks/recreation destinations; and the low-stress network-based BAM measures the comfort levels and willingness to use active transportation modes as a travel option, incorporating bicycle level of stress factors to determine the overall accessibility of the urban greenway network. The three sets of defined BAMs were applied to Portland’s current (2016) and proposed 2035 scenarios. We found that after the implementation of Portland’s “City Greenway” network, all three sets of BAMs showed improvements in accessibility compared to the existing network, although at varying degrees. The improved urban greenway network not only decreased the travel costs of active transportation due to well-connected network and higher comfort and safety levels of cycling, it would also provide increased accessibility to important destinations at lower stress levels within the same distances. Next, we explored the relationship between the bicycle accessibility levels of the urban greenway network and economic indicators. We found positive correlations between two BAMs (distance-based BAM and low-stress network-based BAM) with the number of jobs that are located in each census block. The low-stress network based proximity BAM appears to be the more preferred measure, due to the statistically significant correlations that we found. In addition, the hedonic price model indicated that higher BAM scores were associated with higher property values, particularly for multi-family homes. In general, better BAMs were associated with higher levels of economic activities. The spatial equity analysis examined the how bicycle accessibility is distributed across the metropolitan area and amongst identified historically marginalized communities (including communities with higher populations of people of color, low-income, limited English proficiency, older adults and younger persons), and how the proposed 2035 City Greenways plan might impact these communities differently. We found that the 2035 City Greenways plan, as measured through BAM slightly favor the disadvantaged population. While the distance-based BAM showed significant improvements in accessibility for many of the transportation-disadvantaged communities, the low-stress network-based BAMs showed tempered improvement in these communities. These results indicated that while residents might be better able to access the urban greenway network as more bicycle infrastructure was built, it did not necessarily translate into better access to important destinations without complementary economic development and land use policies expansion along the transportation infrastructure. It also underscores the importance of complementary economic development and land use policies that expand the spatial distribution of important destinations while investing in urban greenway infrastructure or other transportation network improvements

The Effect of Spatial Gradients in Stellar Mass-to-Light Ratio on Black Hole Mass Measurements

We have tested the effect of spatial gradients in stellar mass-to-light ratio (Y) on measurements of black hole masses (MBH) derived from stellar orbit superposition models. Such models construct a static gravitational potential for a galaxy and its central black hole, but typically assume spatially uniform Y. We have modeled three giant elliptical galaxies with gradients alpha = d(log Y)/d(log r) from -0.2 to +0.1. Color and line strength gradients suggest mildly negative alpha in these galaxies. Introducing a negative (positive) gradient in Y increases (decreases) the enclosed stellar mass near the center of the galaxy and leads to systematically smaller (larger) MBH measurements. For models with alpha = -0.2, the best-fit values of MBH are 28%, 27%, and 17% lower than the constant-Y case, in NGC 3842, NGC 6086, and NGC 7768, respectively. For alpha = +0.1, MBH are 14%, 22%, and 17% higher than the constant-Y case for the three respective galaxies. For NGC 3842 and NGC 6086, this bias is comparable to the statistical errors from individual modeling trials. At larger radii, negative (positive) gradients in Y cause the total stellar mass to decrease (increase) and the dark matter fraction within one effective radius to increase (decrease).Comment: 6 pages, 4 figures, 1 table. To appear in ApJ

Stereotactic Radiosurgery Practice Patterns for Brain Metastases in the United States: A National Survey

Background: Stereotactic radiosurgery (SRS) has emerged as an important modality for the treatment of intracranial metastases. There are currently few established guidelines delineating indications for SRS use and fewer still regarding plan evaluation in the treat- ment of multiple brain metastases. Methods: An 18 question electronic survey was distributed to radiation oncologists at National Cancer Institute (NCI) designated cancer centers in the US (60). Centers without radiation oncologists were excluded. Physicians who indicated that they do not prescribe SRS were excluded from the remaining survey questions. Sign test and Chi-square test were used to determine if responses differed significantly from random distribution. Results: 116 of the 697 radiation oncologists surveyed completed the questionnaire, representing 51 institutions. 62% reported treating patients with brain metastases using SRS. Radiation oncologists prescribing SRS most commonly treat CNS (66.2%) and lung (49.3%) malignancies. SRS was used more frequently for \u3c10 brain metastases (73.7%; p\u3c.0001) and whole brain radiation therapy (WBRT) for \u3e10 brain metastases (82.5%; p\u3c.0001). The maximum number of lesions physicians were willing to treat with SRS without WBRT was 1-4 (40.4%) and 5-10 (42.4%) (p\u3c.0001 compared to 11-15, 16-20 and no limit). The most important criteria for choosing SRS or WBRT were number of lesions (p\u3c.0001) and performance status (p=.016). The most common margin for SRS was 0 mm (49.1%; p=.0021). The most common dose constraints other than critical structure was conformity index (84.2%) and brain V12 (61.4%). The LINAC was the most common treatment modality (54.4%) and mono-isocenter technique for multiple brain metastases was commonly used (43.9%; p=.23). Most departments do not have a policy for brain metastases treatment (64.9%; p=.024). Conclusions: This is one of the first national surveys assessing the use of SRS for brain metastases in clinical practice. These data highlight some clinical considerations for physicians treating brain metastases with SRS. Summary: This is among the first national surveys to assess the use of SRS for brain metastases in clinical practice. Specifically, radiation oncologist reported increasingly using SRS instead of WBRT for treating \u3c10 metastases, with the LINAC being the most common modality. Further, treatment parameters considered the most important included 0 mm margins, conformity index, brain V12, and mono- isocenter technique for multiple brain metastases. These results may provide context regarding the use of SRS for brain metastases in clinical practice

The accuracy of small-group estimation and the wisdom of crowds

Abstract We measure the ability of people to estimate the price of familiar household items in a variety of contexts. We manipulate whether estimation is done alone or with others, whether it is done independently or with the knowledge of the estimates of others, and whether it is done in a cooperative or competitive environment. From these basic estimation data, we construct a series of aggregated group estimates, exploring the conditions under which a small group of three people provide the most accurate information. We compare the performance of various small-group estimates to standard Wisdom of Crowds analysis, and find that priming people, or placing them in a cooperative group setting, is less effective than averaging the independent estimates of individuals. We also find, however, that it is possible to extract relatively more information from the decisions people make in a competitive group setting, using cognitive models of their decision-making

Rejuvenation Effect of Aged SBS-Modified Asphalt Utilizing Molecule Analysis

The Performance of Styrene-Butadiene-Styrene Modified Asphalt (SBSMA) is Significantly Impacted by its Aging and Regeneration. in This Research, the Molecular Dynamics Simulation Was Utilized to Investigate the Rejuvenation Effect of Active Reagents on Aged SBS Modified Asphalt through the Following Tasks: 1) Verifying the Accuracy of the Asphalt Model by Density and Solubility Parameters; 2) Assessing the Changes in the Rejuvenated Asphalt Model\u27s Energetic Parameters and Volume Parameters, 3) Studying the Interaction Energy between SBS Molecules and Asphalt Molecule Models, and 4) Evaluating the Relative Concentration, Interfacial Interaction Energy, and Diffusion Effect of the Asphalt-Asphalt Models. the Results Indicated that the Restored Broken SBS Molecule Substantially Impacted the Functionality of the Rejuvenated Asphalt Binder. for Methylene-Bis(4-Cyclohexylisocyanate) (HMDI) and 1,6-Hexanediol Diglycidyl Ether (HDE) Rejuvenated Asphalts, the Non-Bond Energy Decreased Gradually with the Repair of Broken SBS Molecular Structures. the Free Volume Fraction of Rejuvenated Binders Was Lower Than that of SBSMA, indicating that the Compactness and Packing Degree of the Rejuvenated Asphalt Were Increased. the Interaction Energy between SBS and Asphalt Molecules in Rejuvenated Asphalt Increased Because of the Enhanced Van Der Waals Interaction between the Reconstructed SBS Molecule and Rejuvenated Binders. the Free HDE Molecular Chain Reduced the Interaction Energy between SBS and Asphalt Molecules. for the Asphalt-Asphalt Models, the Diffusion Coefficient of the SBSMA-Rejuvenated Asphalt Model Was Lower Than that of the SBSMA-SBSMA Model. the HDE Rejuvenated Asphalt Showed Better Diffusion Behavior Than SBSMA, and SBS Molecules Repaired by HDE Had Excellent Fluidity. the Interfacial Interaction Energy of the SBSMA-Rejuvenated Asphalt Model Was Higher Than that of the SBSMA-SBSMA Model. with the Repair of the Broken SBS Molecular Chain, the Interfacial Interaction Energy between HMDI Rejuvenated Asphalt and SBSMA Increased Gradually. in Contrast, the Interfacial Interaction Energy between HDE Rejuvenated Asphalt and SBSMA Decreased Gradually. the Fully Restored SBS Molecular Structure Had Stable Thermodynamic Properties and Could Accelerate the Diffusion Effect of Rejuvenated Asphalt

Prostate Cancer Metastatic to Bone has Higher Expression of the Calcium-Sensing Receptor (CaSR) than Primary Prostate Cancer

The calcium-sensing receptor (CaSR) is the principal regulator of the secretion of parathyroid hormone and plays key roles in extracellular calcium (Ca2+o) homeostasis. It is also thought to participate in the development of cancer, especially bony metastases of breast and prostate cancer. However, the expression of CaSR has not been systematically analyzed in prostate cancer from patients with or without bony metastases. By comparing human prostate cancer tissue sections in microarrays, we found that the CaSR was expressed in both normal prostate and primary prostate cancer as assessed by immunohistochemistry (IHC). We used two methods to analyze the expression level of CaSR. One was the pathological score read by a pathologist, the other was the positivity% obtained from the Aperio positive pixel count algorithm. Both of the methods gave consistent results. Metastatic prostate cancer tissue obtained from bone had higher CaSR expression than primary prostate cancer (P0.05). The expression of CaSR in cancer tissue was not associated with the stage or status of differentiation of the cancer. These results suggest that CaSR may have a role in promoting bony metastasis of prostate cancer, hence raising the possibility of reducing the risk of such metastases with CaSR-based therapeutics