“GOOD” NEIGHBORHOODS IN PORTLAND,OREGON: FOCUS ON BOTH SOCIAL AND PHYSICAL ENVIRONMENTS

ABSTRACT: We conduct an empirical investigation of the social environment of “good” neighborhoods in physical form in a model of the “compact city,” Portland, Oregon and discuss the implications for design and evaluation of policies inspired by smart growth and new urbanist movements that focus on the urban form and transportation dimensions of neighborhoods, and of housing assistance policies designed to change the economic mix in neighborhoods. We conceptualize the physical and social dimensions of the “good” neighborhood environment and develop an approach to operationalization that uses publicly available data. Our findings indicate that for the most part, Portland has been successful in creating neighborhoods at several economic scales that feature not only the connectivity, accessibility, mixed land use, and access to public transit that characterize “good” neighborhoods from a physical perspective, but also a “good” social environment indicative of strong ties and collective efficacy. However, there are signs that in the process, Portland may be creating poverty areas that lack connectivity, accessibility, and access to public transit and a mix of destinations.     

POTENTIAL FOR BACTERIAL GROWTH ON THE FRESH CUT TROPICAL SQUASH, CALABAZA (CURCUBITA MOSCHATA), DURING STORAGE

Calabaza (Curcubita moschata) is a tropical squash which is gaining popularity as a specialty crop for agricultural producers in the Northeast United States. It is commonly marketed by being cut in half, wrapped in plastic and may be held unrefrigerated until sold. This method of display is essential for consumer acceptance, yet unrefrigerated storage means that some potential for food safety problems exists. Experiments were conducted to determine the potential for bacterial growth during storage of cut calabaza. Freshly cut calabaza contained between 1.3 and 4.7 log₁₀CFU/g aerobic mesophiles. By 10 h, duplicate counts from some samples exceeded 4 log₁₀ CFU/g. After 24 h of room temperature storage, total aerobic plate counts ranged from 5.2 to 7.7 log₁₀ CFU/g. Rapid bacterial growth on cut calabaza stored at room temperature indicates that these products are highly perishable, and may be able to support the growth of pathogenic bacteria, should they be introduced during the slicing process.     

Effect of Water and Serum Absorption on Wear of Unirradiated and Crosslinked UHMWPE Orthopedic Bearing Materials

Abstract

In addition to confounding mass-based wear measurements in serum-lubricated hip simulator experiments, fluid absorption by the acetabular cups may simultaneously modify the wear resistance of the ultra-high molecular weight polyethylene (UHMWPE) from which they are composed. To decouple the fluid absorption and wear processes enabling clearer investigation of this effect, absorption was first imposed during an initial stage where UHMWPE was exposed to pressurized (10 MPa) fluid. This was followed by a second stage, where resultant wear behavior was assessed by a multidirectional pin-on-flat technique that, though still providing a serum-lubricating environment, does not promote the simultaneous fluid absorption occurring in hip simulator testing. Both unirradiated and highly crosslinked UHMWPE were investigated, each with both bovine calf serum and water soaking exposures of duration to 129 days. The pressurized soaking of a highly crosslinked UHMWPE decreased its wear resistance, causing an increase in wear rate by approximately 50% during subsequent serum-lubricated multidirectional pin-on-flat sliding tests as compared to non-soaked material. The magnitude of this effect did not appear to depend on whether the soaking fluid was water or serum, nor did it appear to depend on soak time provided it was at least of a 14-day duration, during which more rapid transient fluid absorption occurs. Such soaking did not produce as pronounced an effect on unirradiated UHMWPE, as its lack of wear resistance likely causes the absorption-affected surface region to be removed within the earliest stages of sliding contact.     

The Evolution of Integrative Capability: Innovation in Cardiovascular Drug Discovery

Recent research has highlighted the ability to integrate fragmentedknowledge across boundaries within a firm as a potentially potentsource of competitive advantage. Yet this research raises apotent tally puzzling question: if these capabilities are socentral to competitive advantage, why do they not instantaneouslydiffuse across an industry? This paper draws on a detailed fieldstudy of the development of hypertensive drugs in 10 major Europeanand American firms to explore this issue. I suggest that anyparticular integrative competence rests on a complex set ofinterlinked factors that usually evolve only slowly over time.Those firms that were fortunate enough to have focused earlyon more 'rational' modes of drug discovery have been much moresuccesssful in developing the integrative capabilities fundamentalto modern drug discovery than those that initially achievedgreat success with the more traditional 'random' method of drugdiscovery. The results thus speak directly to evolutionary theoriesof competence development. They also raise intriguing questionsabout the relationship between the development of competenceand the larger institutional context of the industry, since- both the wealth and prominence of public sector biomedicalresearch and the use of mechanism of action as an integrativedevice appear to have shaped the formation of capability inthe industry.     

LOW‐INCOME HOMEOWNERSHIP: DOES IT NECESSARILY MEAN SACRIFICING NEIGHBORHOOD QUALITY TO BUY A HOME?

ABSTRACT: Questions have been raised about the wisdom of low‐income homeownership policies for many reasons. One potential reason to be skeptical: low‐income homebuyers perhaps may be constrained to purchase homes in disadvantaged neighborhoods. This is a potential problem because home purchases in such neighborhoods: (1) may limit appreciation; (2) may reduce quality of life for adults; and (3) may militate against reputed advantages of homeownership for children. Our study examines the neighborhood conditions of a group of 126 low‐income homebuyers who purchased their first home with assistance from the Home Ownership Program (HOP) operated by the Denver Housing Authority. Our approach is distinguished by its use of a comprehensive set of objective and subjective indicators measuring the neighborhood quality of pre‐move and post‐move neighborhoods. Do low‐income homebuyers sacrifice neighborhood quality to buy their homes? Our results suggest that the answer to this question is more complex than it might at first appear. On the one hand, HOP homebuyers purchased in a wide variety of city and suburban neighborhoods. Nonetheless, a variety of neighborhood quality indicators suggest that these neighborhoods, on average, were indeed inferior to those of Denver homeowners overall and to those in the same ethnic group. However, our analyses also revealed that their post‐move neighborhoods were superior to the ones they lived in prior to homeownership. Moreover, very few HOP destination neighborhoods evinced severe physical, environmental, infrastructural, or socioeconomic problems, as measured by a wide variety of objective indicators or by the homebuyers' own perceptions. Indeed, only 10% of HOP homebuyers perceived that their new neighborhoods were worse than their prior ones, and only 8% held pessimistic expectations about their new neighborhoods' quality of life. Finally, we found that Black homebuyers fared less well than their Latino counterparts, on average, in both objective and subjective measures.     

SUBURBAN DEVELOPMENT AND ECONOMIC SEGREGATION IN THE 1990s

ABSTRACT: Suburbanization is changing the face of urban America. A common claim is that suburban sprawl has contributed to increasing levels of economic segregation, but few studies have directly tested this hypothesis. Using U.S. Census data for 1990 and 2000, this paper examines the trends in and the relationship between suburban development patterns and economic segregation in U.S. metropolitan areas. We find that economic segregation, as measured by the Neighborhood Sorting Index (NSI), declined during the 1990s, reversing the earlier trend. However, results from cross‐sectional and fixed‐effects regression models at the metropolitan level suggest that suburbanization, as measured by five different indicators, was a countervailing influence during the decade. Metropolitan areas that were suburbanizing more rapidly had smaller declines in economic segregation than comparable metropolitan areas.     

Effect of sodium hypochlorite on first instar phylloxera (Daktulosphaira vitifoliae Fitch) mortality

Sodium hypochlorite (NaOCl) is currently recommended for use as a disinfestation treatment for the grape insect pest phylloxera, Daktulosphaira vitifoliae (Homoptera: Phylloxeridae) in Australia. First instar phylloxera is the most active and dispersive stage of the insect and therefore represents a substantial risk of transfer from infested to uninfested vineyards. The dose response experiment reported here tested the effect of three sodium hypochlorite concentrations (0.5 to 2.0%) and immersion times (30 to 600 seconds) on the mortality of first instar phylloxera. One hundred per cent mortality was only achieved when first instars were immersed in 2% sodium hypochlorite for at least 30 seconds. The results are discussed with reference to quarantine recommendations for phylloxera management.     

Dual-mode reflectance and fluorescence near-video-rate confocal microscope for architectural, morphological and molecular imaging of tissue

We have developed a near‐video‐rate dual‐mode reflectance and fluorescence confocal microscope for the purpose of imaging ex vivo human specimens and in vivo animal models. The dual‐mode confocal microscope (DCM) has light sources at 488, 664 and 784 nm, a frame rate of 15 frames per second, a maximum field of view of 300 × 250 μm and a resolution limit of 0.31 μm laterally and 1.37 μm axially. The DCM can image tissue architecture and cellular morphology, as well as molecular properties of tissue, using reflective and fluorescent molecular‐specific optical contrast agents. Images acquired with the DCM demonstrate that the system has the sub‐cellular resolution needed to visualize the morphological and molecular changes associated with cancer progression and has the capability to image animal models of disease in vivo. In the hamster cheek pouch model of oral carcinogenesis, the DCM was used to image the epithelium and stroma of the cheek pouch; blood flow was visible and areas of dysplasia could be distinguished from normal epithelium using 6% acetic acid contrast. In human oral cavity tissue slices, DCM reflectance images showed an increase in the nuclear‐to‐cytoplasmic ratio and density of nuclei in neoplastic tissues as compared to normal tissue. After labelling tissue slices with fluorescent contrast agents targeting the epidermal growth factor receptor, an increase in epidermal growth factor receptor expression was detected in cancerous tissue as compared to normal tissue. The combination of reflectance and fluorescence imaging in a single system allowed imaging of two different parameters involved in neoplastic progression, providing information about both the morphological and molecular expression changes that occur with cancer progression. The dual‐mode imaging capabilities of the DCM allow investigation of both morphological changes as well as molecular changes that occur in disease processes. Analyzing both factors simultaneously may be advantageous when trying to detect and diagnose disease. The DCM's high resolution and near‐video‐rate image acquisition and the growing inventory of molecular‐specific contrast agents and disease‐specific molecular markers holds significant promise for in vivo studies of disease processes such as carcinogenesis.