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71.
This research note examines the changing patterns of work in the British textile industry. It is based upon evidence collected as part of the ESRC's Social Change and Economic Life Research Initiative. The focus is upon the two interpretative frameworks that dominate contemporary analyses: the model of the ‘flexible firm’ and the deskilling thesis. This paper shows that neither model fits the data. British textile mills have become less flexible and technological change has produced more skilled jobs. The industry has become increasingly subject to international competition and requires greater imputs of specialized, highly trained labour. 相似文献
72.
Shelley Penn 《Architectural Design》2006,76(1):114-119
Shelley Penn describes how a Melbourne-based practice's aspirations for integrity and authenticity have led it away from the usual pursuit of an identifiable visual language and style above content. 相似文献
73.
Process planning for rotational parts can be described as deciding on the order of machining the various features. However, this problem entails more details since each feature, hypothetically, can be machined by a left- or a right-hand tool, and in many cases, the parts can be chucked from either end. Another complicating factor is that some features require machining from both directions (with both left- and right-hand tools) and some can be machined by either tool. Thus, the process planning problem for rotational parts decides on the order of machining the various features, the chucking direction and the tool to be used for each feature. Every time the part is chucked or to a lesser extent when the tool direction is changed, the accuracy of the feature is compromised and productivity is reduced due to time spent on non-cutting operations. A good process plan, therefore, should consider the productivity as well as the overall accuracy of the part. This paper presents an algorithmic graph-theoretic approach towards determining the optimal process plan such that the part's overall accuracy is maximized, given the accuracy of the machine and the features tolerances. In particular, we describe the process-planning problem as a generalized travelling salesman problem and then use known procedures to solve the problem. This solution minimizes the overall impact of rechucking operations and tool changes on the process accuracy. Therefore, in addition to the improved precision, the process plan results in faster and more efficient operations. 相似文献
74.
75.
RF Speck ML Penn J Wimmer U Esser BF Hague TJ Kindt RE Atchison MA Goldsmith 《Canadian Metallurgical Quarterly》1998,72(7):5728-5734
To evaluate the feasibility of using transgenic rabbits expressing CCR5 and CD4 as a small-animal model of human immunodeficiency virus type 1 (HIV) disease, we examined whether the expression of the human chemokine receptor (CCR5) and human CD4 would render a rabbit cell line (SIRC) permissive to HIV replication. Histologically, SIRC cells expressing CD4 and CCR5 formed multinucleated cells (syncytia) upon exposure to BaL, a macrophagetropic strain of HIV that uses CCR5 for cell entry. Intracellular viral capsid p24 staining showed abundant viral gene expression in BaL-infected SIRC cells expressing CD4 and CCR5. In contrast, neither SIRC cells expressing CD4 alone nor murine 3T3 cells expressing CCR5 and CD4 exhibited significant expression of p24. These stably transfected rabbit cells were also highly permissive for the production of virions upon infection by two other CCR5-dependent strains (JR-CSF and YU-2) but not by a CXCR4-dependent strain (NL4-3). The functional integrity of these virions was demonstrated by the successful infection of human peripheral blood mononuclear cells (PBMC) with viral stocks prepared from these transfected rabbit cells. Furthermore, primary rabbit PBMC were found to be permissive for production of infectious virions after circumventing the cellular entry step. These results suggest that a transgenic rabbit model for the study of HIV disease may be feasible. 相似文献
76.
Systems whose design is primarily aimed at ensuring efficient, effective and safe working, such as control rooms, have traditionally
been evaluated in terms of criteria that correspond directly to those values: functional correctness, time to complete tasks,
etc. This paper reports on a study of control room working that identified other factors that contributed directly to overall
system safety. These factors included the ability of staff to manage uncertainty, to learn in an exploratory way, to reflect
on their actions, and to engage in problem-solving that has many of the hallmarks of playing puzzles which, in turn, supports
exploratory learning. These factors, while currently difficult to measure or explicitly design for, must be recognized and
valued in design. 相似文献
77.
KK Vithalani CA Parent EM Thorn M Penn DA Larochelle PN Devreotes A De Lozanne 《Canadian Metallurgical Quarterly》1998,9(11):3095-3106
We purified from Dictyostelium lysates an 88-kDa protein that bound to a subset of small GTPases, including racE, racC, cdc42Hs, and TC4ran, but did not bind to R-ras or rabB. Cloning of the gene encoding this 88-kDa protein revealed that it contained multiple armadillo-like repeats most closely related to the mammalian GTP exchange factor smgGDS. We named this protein darlin (Dictyostelium armadillo-like protein). Disruption of the gene encoding darlin demonstrated that this protein is not essential for cytokinesis, pinocytosis, phagocytosis, or development. However, the ability of darlin null cells to aggregate in response to starvation is severely affected. When starved under liquid medium, the mutant cells were unable to form aggregation centers and streams, possibly because of a defect in cAMP relay signaling. This defect was not due to an inability of the darlin mutants to activate adenylate cyclase in response to G protein stimulation. These results suggest that the darlin protein is involved in a signaling pathway that may modulate the chemotactic response during early development. 相似文献
78.
P de Jaegere H Mudra H Figulla Y Almagor S Doucet I Penn A Colombo C Hamm A Bartorelli M Rothman M Nobuyoshi T Yamaguchi V Voudris C DiMario S Makovski D Hausmann S Rowe S Rabinovich M Sunamura GA van Es 《Canadian Metallurgical Quarterly》1998,19(8):1214-1223
OBJECTIVES: A study was set up to validate the safety and feasibility of intravascular ultrasound-guided stenting without subsequent anticoagulation, and its impact on the 6 months restenosis rate. METHODS: The study was designed to be multicentred, prospective, and observational. RESULTS: One hundred and sixty-one patients with stable angina and a de novo coronary artery lesion were enrolled. In four patients, the implantation of a Palmaz-Schatz (with spiral bridge) stent had failed. One of these four patients died 3 days following bypass surgery. In two other patients, intravascular ultrasound assessment was not performed. One hundred and twenty-five of the remaining 155 patients (81%) were treated with aspirin (100 mg x day(-1)), because all three criteria for optimized stent expansion were met. Twenty-two of the remaining 38 patients (25%), in whom at least one criterion was not met were treated with aspirin and acenocoumarol (3 months, INR 2.5-3.5), while 16 patients only received aspirin. Stent thrombosis was documented in two patients (1.3%) for which repeat angioplasty was performed. During the hospital stay, there were no deaths or Q-wave myocardial infarctions. Five patients (3.2%) sustained a non-Q-wave myocardial infarction. During the follow-up period (198+/-38 days, complete for all patients, except one), one patient (0.6%) sustained a Q-wave myocardial infarction, one (0.6%) underwent bypass surgery, and repeat angioplasty was performed in nine patients (5.7%). In two of the nine patients, repeat angioplasty involved another lesion. Therefore, the target lesion revascularization rate during follow-up was 4.5% (seven patients). At quantitative coronary angiography, the minimal lumen diameter (mean+/-SD) increased from 1.12+/-0.34 mm before to 2.89+/-0.35 mm after stenting. Repeat angiography at 6 months was performed in 144 patients (92%). The minimal lumen diameter at follow-up was 2.12+/-0.67 mm. Restenosis (diameter stenosis of 50% or more) was documented in 12 patients or 8.3%. When the two patients with documented stent thrombosis are included, the restenosis rate amounts to 97%. CONCLUSIONS: These data confirm that, in selected patients, stents can safely be implanted without the use of systemic anticoagulation, provided optimal stent expansion is achieved. The exact role of intravascular ultrasound in the achievement of these results needs to be established by appropriately designed studies. In the meantime, intravascular ultrasound coupled with the Palmaz-Schatz stent incorporating a spiral bridge, may have contributed considerably to the immediate angiographic outcome, which in turn may explain the favourable clinical and angiographic outcome at 6 months. 相似文献
79.
Sustainable design and implementation of greywater reuse (GWR) has to achieve an optimum compromise between costs and potable water demand reduction. Studies show that GWR is an efficient tool for reducing potable water demand. This study presents a multi-objective optimization model for estimating the optimal distribution of different types of GWR homes in an existing municipal sewer system. Six types of GWR homes were examined. The model constrains the momentary wastewater (WW) velocity in the sewer pipes (which is responsible for solids movement). The objective functions in the optimization model are the total WW flow at the outlet of the neighborhoods sewer system and the cost of the on-site GWR treatment system. The optimization routing was achieved by an evolutionary multi-objective optimization coupled with hydrodynamic simulations of a representative sewer system of a neighborhood located at the coast of Israel. The two non-dominated best solutions selected were the ones having either the smallest WW flow discharged at the outlet of the neighborhood sewer system or the lowest daily cost. In both solutions most of the GWR types chosen were the types resulting with the smallest water usage. This lead to only a small difference between the two best solutions, regarding the diurnal patterns of the WW flows at the outlet of the neighborhood sewer system. However, in the upstream link a substantial difference was depicted between the diurnal patterns. This difference occurred since to the upstream links only few homes, implementing the same type of GWR, discharge their WW, and in each solution a different type of GWR was implemented in these upstream homes. To the best of our knowledge this is the first multi-objective optimization model aimed at quantitatively trading off the cost of local/onsite GW spatially distributed reuse treatments, and the total amount of WW flow discharged into the municipal sewer system under unsteady flow conditions. 相似文献
80.
Non-linear optothermal properties of metal-free phthalocyanine 总被引:1,自引:0,他引:1
Hossin A. Abdeldayem Donald O. Frazier Benjamin G. Penn David D. Smith Curtis E. Banks 《Thin solid films》1999,350(1-2):245-248
The non-linear optical properties of metal-free phthalocyanine (MFPC) thin films were examined using the second harmonic at 532 nm from a pulsed Nd:YAG laser, and the continuous wave He–Ne and Ar+ lasers. The He–Ne laser transmission at fixed input intensity was found to increase temporally within a period of 12 h. The third-order non-linear susceptibilities (χ(3)) by four-wave mixing were measured for films of different thickness. The saturation intensity of MFPC, and its absorption cross-section, at 633 nm from a He–Ne laser, are reported. An optical bistability was recorded using a He–Ne laser. An AND logic gate was also demonstrated in the system. These phenomena in the system are attributed to refractive index modulation by thermal excitations. 相似文献