This paper explores the contribution of the structural transformation and urbanization process in the housing market in China. City migration ‡ows combined with an inelastic land supply, due to entry restrictions, has raised house prices. This issue is examined using a multi-sector dynamic general-equilibrium model with migration and housing market. Our quantitative …ndings suggest that this process accounts for about 80 percent of urban housing prices. This mechanism remains valid in an extension calibrated to the two largest cities where housing booms have been particularly noticeable. Overall, supply factors and productivity account for most of the housing price growth.
The rightward regulatory region of bacteriophage lambda contains two promoters, p RM and p R , which direct the synthesis of nonoverlapping divergent transcripts from start sites 82 bp apart. Each of the two promoters has an upstream (A؉T)-rich region (ATR) within the sequence from ؊40 to ؊60 where in the rrnB P1 promoter a stretch of 20 (A؉T) bp greatly stimulates promoter function. Here we present an investigation of the possible functional significance of p RM 's ATR. We determined the effects on RNA polymerase-p RM promoter interaction both of (G؉C) substitutions in the ATR and of amino acid substitutions in the ␣ subunit, known to affect the upstream interaction. We find small (two-to threefold) effects of selected mutations in the ␣ subunit on open complex formation at p RM . However, the (presumably upstream) interactions underlying these effects are sequence nonspecific, as they are not affected by ( The rightward regulatory region of bacteriophage lambda contains two promoters, p R and p RM , which are divergently transcribed from start sites separated by only 82 bp (25). Open complex formation at the p R promoter is much faster than at p RM ; therefore, the vast majority of RNA polymerases (RNAPs) forming an open complex at the latter promoter do so on a fragment that already contains a polymerase at p R . It was found by us (14, 15) as well as by Gussin's group (6, 28) that mutations which inactivate the p R promoter facilitate open complex formation at p RM . These results suggest that p R -bound RNAP interferes with open complex formation at p RM . Surprisingly, a 10-bp deletion between the two promoters appears to abolish the interference (22), as it results in increased activity of p RM whether p R is inactivated by mutation or not.The identity of promoters for Escherichia coli RNAP is mostly determined by two DNA elements, the Ϫ10 and Ϫ35 regions (21). The ability to recognize these two regions is imparted upon the RNAP holoenzyme by its subunit (12). The promoters for E. coli rRNA (27), as well as some other strong promoters in E. coli (17)(18)(19) and Bacillus subtilis (2, 13), have been found to additionally have (AϩT)-rich regions (ATRs) upstream of bp Ϫ40. These so-called UP elements (27) are typically 20 bp in length. Transcription in vivo and in vitro (27) as well as the rate of open complex formation at the rrnB P1 promoter (26) was decreased by more than 10-fold because of deletion of this UP element. The C-terminal domain (amino acids 249 to 329 [3,23]) of the ␣ subunit of RNAP has been implicated in UP element recognition: deletion of this domain greatly impaired the ability of RNAP to respond to the UP element both in vivo and in vitro (27). In subsequent studies, amino acid substitutions in the ␣ subunit were employed to pinpoint the amino acids involved in the interaction with the UP element to those at positions 262 to 269 and 296 to 299 (8). Recent determinations of the structure of the Cterminal domain of the ␣ subunit show that the location of these amino acids is compatible wit...
Objectives: To determine if high-resolution T2-weighted (HRT2) magnetic resonance imaging (MRI) is a comparably accurate and economical alternative to the gold standard of contrast-enhanced T1-weighted (T1C) MRI for surveillance of know vestibular schwannomas (VSs).Study Design: Retrospective case-control analysis, systematic review, and economic evaluation. Methods: Vestibular schwannoma size in anteroposterior, mediolateral, and superoinferior axes were measured by two neuroradiologists, both blinded to previous measurements, for 50 randomized patients with T1C and HRT2 on two separate occasions. Measurements were assessed by Pearson product-moment correlation coefficients, and differences were analyzed by Student t test. Once the data were analyzed, appropriate economic evaluation was performed utilizing institutional-, federal-, and literature-based estimates of cost and incidence/prevalence.Results: Pearson correlations (r) between T1C and HRT2 were 0.991 and 0.973 for radiologists 1 and 2, respectively, with no statistically significant differences (P 0.05) between imaging techniques. Intraobserver and interobserver reliability estimates (j) were 0.88 to 1 for both T1C and HRT2, indicating very high reliability. Cost-minimization analysis demonstrated cost and charge differences of $148.02 and $1,284 per patient per scan, respectively. This represents an overall cost and charge savings for this 50-patient cohort of $7,401 and $64,200, respectively.Conclusion: HRT2 imaging is a highly reliable and lower-cost alternative to T1C for follow-up surveillance scans in patients with VS.
Background: As the booming of deep learning era, especially the advances in convolutional neural networks (CNNs), CNNs have been applied in medicine fields like radiology and pathology. However, the application of CNNs in dermatology, which is also based on images, is very limited. Inflammatory skin diseases, such as psoriasis (Pso), eczema (Ecz), and atopic dermatitis (AD), are very easily to be mis-diagnosed in practice. Methods: Based on the EfficientNet-b4 CNN algorithm, we developed an artificial intelligence dermatology diagnosis assistant (AIDDA) for Pso, Ecz & AD and healthy skins (HC). The proposed CNN model was trained based on 4,740 clinical images, and the performance was evaluated on experts-confirmed clinical images grouped into 3 different dermatologist-labelled diagnosis classifications (HC, Pso, Ecz & AD). Results:The overall diagnosis accuracy of AIDDA is 95.80%±0.09%, with the sensitivity of 94.40%±0.12% and specificity 97.20%±0.06%. AIDDA showed accuracy for Pso is 89.46%, with sensitivity of 91.4% and specificity of 95.48%, and accuracy for AD & Ecz 92.57%, with sensitivity of 94.56% and specificity of 94.41%.Conclusions: AIDDA is thus already achieving an impact in the diagnosis of inflammatory skin diseases, highlighting how deep learning network tools can help advance clinical practice.
Bacteriophage promoters P R and P RM direct RNA synthesis in divergent orientations from start sites 82 base pairs apart. We had previously determined that the presence on the same DNA fragment of a wild type P R promoter interfered with the utilization of the P RM promoter. The results reported here concern the effects of changing the distance between the start sites by insertion or deletion of 5 or 10 base pairs. Three different techniques (run-off transcription, gel mobility shift, and permanganate probing) were employed to monitor complex formation at P RM . Unexpectedly we find that deletion of 10 base pairs between the start sites abolishes the interference, whereas insertion of 10 base pairs does not. Deletion of 5 base pairs, however, essentially prevents joint complex formation at P R and P RM . These findings suggest several ways in which for the wild type separation of the two promoters the utilization of P RM could be affected by an RNA polymerase at P R . In addition to direct steric interference, these include the obstruction of access to DNA sites necessary for optimal contact with the RNA polymerase.Promoters P R and P RM of bacteriophage direct the synthesis of nonoverlapping, divergent transcripts originating from start sites separated by 82 base pairs. We (1, 2) as well as Gussin and co-workers (3, 4) have shown that the presence of the P R promoter has a negative effect on the ability of RNA polymerase to form open complexes at P RM . The use of P R mutants allowed Gussin's group to demonstrate that conversely, the presence of an RNA polymerase at P RM negatively affects the utilization of a (weakened) P R promoter as well (5).Open complex formation at the wild type P R promoter occurs within seconds (6, 7), but formation of the complex at P RM is several orders of magnitude slower, on the time scale of tens of minutes (1,3,8). Thus nearly every RNA polymerase binding at P RM does so in the context of another polymerase situated at P R . Our own work (1, 2) as well as more extensive kinetic analysis by Gussin and his group (3, 4) has demonstrated that the interference with complex formation at P RM manifests itself not at the initial bimolecular (binding) step but rather in some subsequent step involving conformational transitions in RNA polymerase and/or DNA. The interference slows down but does not prevent open complex formation at P RM ; ultimately open complexes at both promoters do co-exist on the same DNA fragment (Refs. 1 and 9 and this work).Reduction of the distance between P R and P RM by one base pair further slows open complex formation at P RM (4). The effects of considerably shorter separation between the P R and P RM promoters can be assessed from studies on other lambdoid phages. For the 434 phage where the distance between the start sites of P R and P RM is about 65 base pairs, the Ϫ35 regions of the two promoters overlap and concurrent binding of RNA polymerases at the two promoters is not observed (10). For P22 the interpromoter distance is even shorter, making it quite unl...
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