The Impact of the Carrollton GreenBelt on Residential Housing Prices: A Spatial Approach

The Carrollton GreenBelt is a linear park encircling the City of Carrollton Georgia. The GreenBelt differs from other linear parks in that it is an entirely new construction and was not built upon existing rail lines, as was the Atlanta Beltline and the nearby Silver Comet Trail. Using GIS, data from the Carroll County Tax Assessor\u27s office and spatial econometric techniques, we estimate local fair-market housing values within the hedonic framework to measure the relationship between home prices and access to the GreenBelt. We find the expected positive effects from the number of bedrooms, bathrooms and square footage, but access to the GreenBelt is associated with lower housing sale prices during the period; however, these lower prices may also be the result of conscious location decisions of the GreenBelt developers in an attempt to lower land acquisition costs in the development phase. Despite our efforts to control for distance to the center of the city, the negative association between the GreenBelt and housing values may be impacted by the endogeneity between GreenBelt location and residential housing prices

The Rationality of Prejudices

We model an -player repeated prisoner's dilemma in which players are given traits (e.g., height, age, wealth) which, we assume, affect their behavior. The relationship between traits and behavior is unknown to other players. We then analyze the performance of “prejudiced” strategies—strategies that draw inferences based on the observation of some or all of these traits, and extrapolate the inferred behavior to other carriers of these traits. Such prejudiced strategies have the advantage of learning rapidly, and hence of being well adapted to rapidly changing conditions that might result, for example, from high migration or birth rates. We find that they perform remarkably well, and even systematically outperform both Tit-For-Tat and ALLD when the population changes rapidly

Differences in designations of observation care in US freestanding children's hospitals: Are they virtual or real?

OBJECTIVE: To characterize practices related to observation care and to examine the current models of pediatric observation medicine in US children's hospitals. DESIGN: We utilized 2 web‐based surveys to examine observation care in the 42 hospitals participating in the Pediatric Health Information System database. We obtained information regarding the designation of observation status, including the criteria used to admit patients into observation. From hospitals reporting the use of observation status, we requested specific details relating to the structures of observation care and the processes of care for observation patients following emergency department treatment. RESULTS: A total of 37 hospitals responded to Survey 1, and 20 hospitals responded to Survey 2. Designated observation units were present in only 12 of 31 (39%) hospitals that report observation patient data to the Pediatric Health Information System. Observation status was variably defined in terms of duration of treatment and prespecified criteria. Observation periods were limited to <48 hours in 24 of 31 (77%) hospitals. Hospitals reported that various standards were used by different payers to determine observation status reimbursement. Observation care was delivered in a variety of settings. Most hospitals indicated that there were no differences in the clinical care delivered to virtual observation status patients when compared with other inpatients. CONCLUSIONS: Observation is a variably applied patient status, defined differently by individual hospitals. Consistency in the designation of patients under observation status among hospitals and payers may be necessary to compare quality outcomes and costs, as well as optimize models of pediatric observation care. Journal of Hospital Medicine 2012;. © 2011 Society of Hospital Medicine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91108/1/949_ftp.pd

A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster

We present a CCD-based photometric survey covering 870 sq. arcmin in a young stellar cluster around the young multiple star sigma Orionis. Our survey limiting R, I, and Z magnitudes are 23.2, 21.8, and 21.0, respectively. From our colour-magnitude diagrams, we have selected 49 faint objects, which smoothly extrapolate the photometric sequence defined by more massive known members. Adopting the currently accepted age interval of 2-10 Myr for the Orion 1b association and considering recent evolutionary models, our objects may span a mass range from 0.1 down to 0.02 Msun, well within the substellar regime. Follow-up low-resolution optical spectroscopy (635-920 nm) for eight of our candidates (I=16-19.5) shows that they have spectral types M6-M8.5 which are consistent with the expectations for true members. Compared with their Pleiades counterparts of similar types, Halpha emission is generally stronger, while NaI and KI absorption lines appear weaker, as expected for lower surface gravities and younger ages. Additionally, TiO bands and in particular VO bands appear clearly enhanced in our candidate with the latest spectral type, SOri 45 (M8.5, I=19.5), compared to objects of similar types in older clusters and the field. We have estimated the mass of this candidate at only 0.020-0.040 Msun, hence it is one of the least massive brown dwarfs yet discovered. We also discuss in this paper the potential role of deuterium as a tracer of both substellar nature and age in very young clusters.Comment: Accepted for publication in ApJ Main Journal. 32 pages of text and tables + 9 pages of figures. Figures 3a and 3b (gif format) provided separatel

Polyethylene imine-based receptor immobilization for label free bioassays

Polyethylene imine (PEI) based immobilization of antibodies is described and the concept is proved on the label free assay of C-Reactive Protein (CRP). This novel immobilization method is composed of a hyperbranched PEI layer which was deposited at a high pH (9.5) on the sensor surface. The free amino groups of PEI were derivatized with neutravidin by Biotin N-hydroxysuccinimide ester and the biotinylated anti-CRP antibody immobilized on this layer. Direct binding assay of recombinant CRP was successfully performed in the low μg/ml concentrations using a label free optical waveguide biosensor

Observation‐status patients in children's hospitals with and without dedicated observation units in 2011

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111995/1/jhm2339.pd

Pediatric observation status: Are we overlooking a growing population in children's hospitals?

BACKGROUND: Inpatient administrative datasets often exclude observation stays, as observation is considered to be outpatient care. The extent to which this status is applied to pediatric hospitalizations is not known. OBJECTIVE: To characterize trends in observation status code utilization and 1‐day stays among children admitted from the emergency department (ED), and to compare patient characteristics and outcomes associated with observation versus inpatient stays. DESIGN: Retrospective longitudinal analysis of the 2004–2009 Pediatric Health Information System (PHIS). SETTING: Sixteen US freestanding children's hospitals contributing outpatient and inpatient data to PHIS. PATIENTS: Admissions to observation or inpatient status following ED care in study hospitals. MEASUREMENTS: Proportions of observation and 1‐day stays among all admissions from the ED were calculated each year. Top ranking discharge diagnoses and outcomes of observation were determined. Patient characteristics, discharge diagnoses, and return visits were compared for observation and 1‐day stays. RESULTS: The proportion of short‐stays (including both observation and 1‐day stays) increased from 37% to 41% between 2004 and 2009. Since 2007, observation stays have outnumbered 1‐day stays. In 2009, more than half of admissions from the ED for 6 of the top 10 ranking discharge diagnoses were short‐stays. Fewer than 25% of observation stays converted to inpatient status. Return visits and readmissions following observation were no more frequent than following 1‐day stays. CONCLUSIONS: Children admitted under observation status make up a substantial proportion of acute care hospitalizations. Analyses of inpatient administrative databases that exclude observation stays likely result in an underestimation of hospital resource utilization for children. Journal of Hospital Medicine 2012; © 2012 Society of Hospital MedicinePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93720/1/1923_ftp.pd