9,123 research outputs found
Neighborhood Dynamics and Price Effects of Superfund Site Clean-Up
This report uses census data to analyze the price effects of superfund site clean-up, inclusive of both direct price effects and indirect effects through clean-up's effect on neighborhood demographic transitions and reinvestment in the housing stock. FRC Report 11
Effects of Inhaled Brevetoxins in Allergic Airways: Toxin–Allergen Interactions and Pharmacologic Intervention
During a Florida red tide, brevetoxins produced by the dinoflagellate Karenia brevis become aerosolized and cause airway symptoms in humans, especially in those with pre-existing airway disease (e.g., asthma). To understand these toxin-induced airway effects, we used sheep with airway hypersensitivity to Ascaris suum antigen as a surrogate for asthmatic patients and studied changes in pulmonary airflow resistance (R(L)) after inhalation challenge with lysed cultures of K. brevis (crude brevetoxins). Studies were done without and with clinically available drugs to determine which might prevent/reverse these effects. Crude brevetoxins (20 breaths at 100 pg/mL; n = 5) increased R (L) 128 ± 6% (mean ± SE) over baseline. This bronchoconstriction was significantly reduced (% inhibition) after pretreatment with the glucocorticosteroid budesonide (49%), the β (2) adrenergic agent albuterol (71%), the anticholinergic agent atropine (58%), and the histamine H(1)-antagonist diphenhydramine (47%). The protection afforded by atropine and diphenhydramine suggests that both cholinergic (vagal) and H(1)-mediated pathways contribute to the bronchoconstriction. The response to cutaneous toxin injection was also histamine mediated. Thus, the airway and skin data support the hypothesis that toxin activates mast cells in vivo. Albuterol given immediately after toxin challenge rapidly reversed the bronchoconstriction. Toxin inhalation increased airway kinins, and the response to inhaled toxin was enhanced after allergen challenge. Both factors could contribute to the increased sensitivity of asthmatic patients to toxin exposure. We conclude that K. brevis aerosols are potent airway constrictors. Clinically available drugs may be used to prevent or provide therapeutic relief for affected individuals
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UPC++ v1.0 Programmer’s Guide, Revision 2020.3.0
UPC++ is a C++11 library that provides Partitioned Global Address Space (PGAS) programming. It is designed for writing parallel programs that run efficiently and scale well on distributed-memory parallel computers. The PGAS model is single program, multiple-data (SPMD), with each separate constituent process having access to local memory as it would in C++. However, PGAS also provides access to a global address space, which is allocated in shared segments that are distributed over the processes. UPC++ provides numerous methods for accessing and using global memory. In UPC++, all operations that access remote memory are explicit, which encourages programmers to be aware of the cost of communication and data movement. Moreover, all remote-memory access operations are by default asynchronous, to enable programmers to write code that scales well even on hundreds of thousands of cores
Neighborhood dynamics and price effects of Superfund site clean-up
Numerous hedonic price analyses estimate price effects associated with hazardous waste site remediation or other environmental variation. This paper estimates a neighborhood transition model to capture the direct price effect from Superfund site clean-up and the indirect price effects arising from residential sorting and changes in investment in the housing stock following clean-up. First-difference models of neighborhood change and a national sample are used. This approach fails to find consistent positive direct price effects. Positive indirect effects, however, may arise through residential sorting and neighborhood investment spurred by remediation. The findings can be sensitive to policy endogeneity and model specification
Self-Organization Threshold Scaling for Thermal Atoms Coupled to a Cavity
We make a detailed experimental study of the threshold for the
self-organization of thermal 87Rb atoms coupled to a high-finesse cavity over a
range of atom numbers and cavity detunings. We investigate the difference
between probing with a traveling wave and a retroreflected lattice. These two
scenarios lead to qualitatively different behavior in terms of the response of
the system as a function of cavity detuning with respect to the probe. In both
cases, we confirm a N-1 scaling of the threshold with atom number.Comment: 4 pages, 3 figure
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