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51.
Problem: Immigration poses various problems for U.S. cities and regions, and the roles planners should play in migrant communities are not clear.

Purpose: I consider how practitioners and scholars have understood and addressed the planning challenges and opportunities presented by the major migrations of ethnic minorities to U.S. cities and regions over the past century.

Methods: I trace discussions of planning and migration at professional planning conferences over the past century and survey planning scholarship and practice related to immigration and migrant communities in three principal eras: early 20th century southern and eastern European immigration; the mid-century internal migrations of African Americans and Puerto Ricans; and immigration in the late 20th and early 21st century.

Results and conclusions: Over the past century, immigration has had physical, economic, and social effects on people and places that are legitimate concerns of urban planners. Yet, the planning profession has had an ambiguous and often ambivalent relationship with migrant communities and has struggled to define specific roles for planners within those communities while social workers and other community and economic development practitioners played larger roles. Planning scholars have not paid as much attention to migrants' adaptation and mobility in U.S. society or their impacts on receiving communities, labor markets, housing, and congestion as have other scholars and urbanists.

Takeaway for practice: Planners have engaged with migrants in a variety of ways. Understanding this history provides context for contemporary debates about immigration and helps frame challenges and opportunities in migrant and receiving communities as planning problems.

Research support: None.  相似文献   
52.
Corsini  P. Prete  C.A. 《Micro, IEEE》1986,6(3):26-33
Intended for designers of kernels for distributed multinode systems, this debugger enables them to work in a Unix environment and to interact with the target nodes via a console.  相似文献   
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The discrimination capability of avalanche counters to detect different ionizing particles has been studied using a 252Cf source. Pulse height, pulse-height resolution and timing properties have been measured as a function of the reduced applied voltage for parallel-plate and parallel-grid avalanche counters. At the highest applied voltages, space charge effects shift the pulse-height signal of the avalanche counter away from being linearly proportional to the stopping power of the detected particles and cause the pulse-height resolution to deteriorate. To optimize the avalanche counter capability, without loss of time resolution, it appears better to operate the detector at voltages well below the breakdown threshold. Measurements with 32S ions are also reported.  相似文献   
58.
Selective production of exotic species (SPES) is an ISOL-based accelerator facility that will be built in the Legnaro INFN Laboratory (Italy), intended to provide an intense neutron-rich radioactive ion beams obtained by proton induced fission of an uranium carbide target. Beside this main target, a silicon carbide (SiC) target will the first to be used to deliver some p-rich beams. This target will validate also the functionality of the SPES facility with aluminum beam as result of hitting SiC target with protons. In the past off-line studies on laser photoionization of aluminum have performed in Pavia Spectroscopy Laboratory and in Laboratori Nazionali di Legnaro where, recently, a XeCl excimer laser was installed in order to test the laser ionization in the SPES hot cavity. Results are promising to justify further studies with this technique, aiming a better characterization of the SPES ion extraction capability under laser photoionization.  相似文献   
59.
We have developed a Paradox-based data collection and management system for large-scale multi-site randomized clinical trials. The system runs under Windows operating system and integrates Symantec pcAnywhere32 telecommunications software for data transmission and remote control sessions, PKZIP utility for the compression/decompression of transmitted data, and Stat/Transfer for exporting the centralized Paradox database for analyses. We initially developed this system for VA Cooperative Study #399 'The Effect of Antiarrhythmic Therapy in Maintaining Stability of Sinus Rhythm in Atrial Fibrillation', which collects over 1000 variables on 706 patients at 20 sites. Patient intake for this 5-year study began in March of 1998. We have also developed an enhanced version of this system, which is being used in the NIH-funded 'Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT)' that collects over 1200 variables on 1588 patients at 13 sites. Patient intake for this 4-year study began in October of 2000.  相似文献   
60.
Methane is a widespread energy source and can serve as an attractive C1 building block for a future bioeconomy. The soluble methane monooxygenase (sMMO) is able to break the strong C−H bond of methane and convert it to methanol. The high structural complexity, multiplex cofactors, and unfamiliar folding or maturation procedures of sMMO have hampered the heterologous production and thus biotechnological applications. Here, we demonstrate the heterologous production of active sMMO from the marine Methylomonas methanica MC09 in Escherichia coli by co-synthesizing the GroES/EL chaperonin. Iron determination, electron paramagnetic resonance spectroscopy, and native gel immunoblots revealed the incorporation of the non-heme diiron centre and homodimer formation of active sMMO. The production of recombinant sMMO will enable the expansion of the possibilities of detailed studies, allowing for a variety of novel biotechnological applications.  相似文献   
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