CO2 Park

On lucky occasions, one gets the Big Idea—the concept that will guide and critique the entire design process. It is usually to that concept that the designer returns to test out decisions. But for us the designing of CO₂ Park worked a bit differently: We started with an inkling of an idea—a fascination with the natural phenomenon, Aurora Borealis—and worked our way through the project as if we were following a thin and barely discernible thread. One idea engendered the next. Often we had barely finished what we had set our minds to before we were moving off in another direction. When we seemed to be at a dead end, we did not look to the concept for answers; instead, we turned back to the last successful model, sketch, or thought to find our direction.     

Concerted regulation of low density lipoprotein receptor gene expression by follicle-stimulating hormone and insulin-like growth factor I in porcine granulosa cells: promoter activation, messenger ribonucleic acid stability, and sterol feedback

The consequences of glucocorticoid receptor (GR) dysfunction for neuroimmunoendocrine responses to an inflammatory challenge were studied in transgenic mice expressing antisense RNA directed against the GR [GR-impaired (GR-i) mice]. Mice were implanted intraperitoneally with a biotelemetry transmitter to monitor body temperature and locomotion. GR-i mice showed decreased locomotion and body temperature during the dark phase of the diurnal cycle. Intraperitoneal administration of saline caused a rapid increase in body temperature in control mice, which was terminated within 90 min. In GR-i mice, however, body temperature remained elevated for about 6 h. Intraperitoneal injection of endotoxin (10 micrograms/mouse) produced a biphasic fever in control mice. However, in endotoxin-injected GR-i mice, body temperature was not significantly different from their saline-injected controls during the first 6 h. Body temperature then increased and remained elevated during the night period. Both strains showed hypolocomotion after endotoxin. In a second experiment, mice were injected intraperitoneally with saline or endotoxin and killed after 1, 3, 6 or 24 h. In GR-i mice, endotoxin caused an augmented rise in plasma ACTH, but not in corticosterone levels. The endotoxin-induced increase in serum levels of interleukin-1 beta and interleukin-6 was not different between the strains. However, whereas in control mice tumour necrosis factor-alpha levels were below detection at the time points studied, substantial levels of this cytokine were found in the serum of GR-i mice 1 h after endotoxin administration. It may be concluded that life-long impairment of GR evolves in aberrant physiological and humoral responses to an acute inflammatory challenge. These findings expand our understanding about the neuroendocrine and physiological disturbances associated with stress-related disorders.     

A randomized, controlled trial of a behavioral intervention to prevent sexually transmitted disease among minority women

Using annual bite-wing radiographs, the incidence and progression of approximal caries (4d-7m) were assessed longitudinally in teenagers and adolescents whose treatment had been based on remineralizing rather than restorative strategies. A closed cohort of 536 children initially was followed from 11 to 22 years of age. The scoring system was: 0 = no visible radiolucency; 1-2 = radiolucency in the enamel up to the enamel-dentin border; 3 = radiolucency with a broken enamel-dentin border but with no obvious progression in the dentin; 4 = radiolucency with obvious spread in the outer half of the dentin, and 5 = radiolucency in the inner half of the dentin. Caries rates were estimated as the number of new lesions/100 tooth surface-years, and the Kaplan-Meier estimate was used to calculate the cumulative survival time of each approximal surface. Three events were used: the transitions from states 0 to 2, 2 to 4 and 3 to 4. The results showed a considerable variation between the surfaces in both caries rates and survival time. For all surfaces combined, the median caries rate from state 0 to 2 was 3.9 new lesions/100 tooth surface-years; from state 2 to 4, the rate was 5.4, and from state 3 to 4 it was 20.3. Of the sound surfaces (state 0), 75% survived 6.3 years without reaching state 2. Given state 2, 75% survived 4.8 years without reaching the outer half of the dentin (state 4), while given a lesion at the enamel-dentin border (state 3), 75% survived 1.3 years without doing the same. The median survival time of lesions from state 3 to 4 was 3.1 years. The group with DMFSappr>1 at the age of 11-12 years had a risk of new approximal enamel lesions (state 0-2) that was 2.5 times greater than that of the group with DMFSappr = 0-1.     

Differential sensitivity of myosin-heavy-chain-typed fibers to distinct aggregates of nerve-mediated activation

We studied the regulatory effects of nerve-mediated activity on the early expression of embryonic and adult myosin heavy chains (MHC) within inactive though still innervated rat plantaris and soleus muscle fibers. To this end, we stimulated motor nerves that were quiescent following treatment with tetrodotoxin (TTX) with paradigms designed to partition the influence of neural activation frequency and assessed the selective expression and accumulation of MHCs within muscle fibers using an array of specific antibodies. We show rapid de novo expression of IIx MHC within select soleus fibers in response to high-frequency activation for more than 0.01% of daily time. High-frequency aggregates were also the most effective in preventing the TTX-induced reexpression of embryonic MHCs within specific fibers. Only configurations that included high-frequency trains for more than 0.01% of daily time or combined with 10 Hz stimulation preserved the size of select fibers, used as a measure of the net cellular content of MHC. The effectiveness of this preservation varied according to the muscle type and MHC expressed, and, in a subset of fibers, was influenced by contractile loading status. Our results demonstrate that distinct subsets of MHC-typed fibers are differentially sensitive to the neural activation cues mediating the cellular expression of these proteins.     

The European construction industry and its competitiveness: a construct of the European Commission

The 'European construction industry' is a fiction that tends to obscure its heterogeneous character and to mar studies and policies of the European Commission aimed at improving the internal and external 'competitiveness' of the sector. In order to assess the process of integration in Europe under the impact of its own dynamics as well as Union policies, this paper looks at the dynamics of the sector from three different aspects: as investment, production and labour process. It shows, in particular, the persistent regional and social disparities dividing the industry into separate entities. Political attention tends to focus on a small number of construction companies competing for a few projects which represent the European dimension. Yet, these companies still rely on their respective national bases and local labour from the place where construction is carried out. Persistent divisions between the states are also reflected in the low level of transnational organization of the construction industry. The policy of the European Commission generally ignores these divisions and attempts to establish principles intended to make a whole sector more 'competitive', while its component parts, operating at hugely different levels of productivity, do not even meet on the same market. This paper argues that, instead of trying in vain to introduce a 'knock-out' system of competition in the EU Member States, a targeted approach might help raise productivity in lagging regions and thus improve the basis of competitiveness on global markets.     

LAGRANGEAN RELAXATION AND SUBGRADIENT OPTIMIZATION APPLIED TO OPTIMAL DESIGN WITH DISCRETE SIZING

The discrete sizing problem in optimal design is adressed. Lagrangean dual approaches earlier published are briefly reviewed and it is noted that quite sophisticated procedures have been used to solve the dual problems. The simple concept of Lagrangean relaxation combined with subgradient optimization and Lagrangean heuristics has, however, not been applied to the discrete sizing problem. In this paper a scheme based on this concept is described and tested on some small problems. The results indicate that subgradient optimization is completely capable of solving the dual problem. Moreover it is possible to devise heuristics that construct feasible solutions to the original problem, using the Lagrangean subproblem solution.     

Short-term effects of thyroid hormones on the Na/H antiport in L-6 myoblasts: high molecular specificity for 3,3',5-triiodo-L-thyronine

The thyroid hormones L-T3 and L-T4 were shown to activate the Na/H antiport in L-6 cells from rat skeletal muscle by a rapid, nongenomic mechanism. Under pH equilibrium conditions, a significant rise in the intracellular pH, measured by the fluorescent pH indicator 2',7'-bis-(carboxyethyl)-5(6)-carboxyfluorescein was observed after the addition of physiological concentrations (10(-10) M) of either L-T3 or L-T4, but with different time courses. L-T3 at all concentrations increased the pH after a delay of 2 min, whereas L-T4 showed a concentration-dependent lag time, going from 11 min at 10(-11) M down to 5 min for a hormone concentration of 10(-6) M. The effect of L-T4 was blocked in the presence of the 5'-deiodinase inhibitor 6-n-propyl-2-thiouracil, suggesting that the difference in lag time between L-T3 and L-T4 was due to the 5'-deiodination process that transforms L-T4 into the bioactive L-T3. In short term studies (<5 min), a high molecular specificity for L-T3 was found, as L-T4, rT3, the D-isomer of T3, and the deaminated analogues were ineffective at physiological concentrations. In analogy with the results found at equilibrium, intracellular pH recovery from an acid load and set-point were increased after 2 min for L-T3 (10(-9) M) and after 10 min for L-T4 (10(-9) M). The effect of the hormones on the intracellular pH was completely blocked by the specific antiport inhibitor 5-(ethyl-N-isopropyl)amiloride. These findings suggest that thyroid hormones may play an active role in the recovery from muscular acidosis through direct stimulation of the Na/H antiport.