Development of price models for architectural and environmental quality for residential developments in Hong Kong.

Factors affecting a residential unit's price are always of interest to homebuyers and building developers, especially in a city like Hong Kong which is known for expensive housing. Literature review indicates that the governing factors can be categorized into architectural and environmental attributes. Among different methods commonly used for pricing, the hedonic price approach is viewed as the most suitable. However, the successful use of this method requires that homebuyers know and choose the attributes. Whilst choosing architectural attributes are not a problem for homebuyers, the same does not apply to environmental attributes. Previous studies by the authors have proposed some simple indicators for quantifying the environmental attributes. Based upon the developed performance indicators and the transaction records of two representative housing estates (Royal Ascot = RA and City One Shatin = COS), details of the properties, including transaction prices, architectural particulars and environmental characteristics were numerically transformed for the hedonic price analysis. The analysis results revealed that the willingness to pay (percentage of house price in parenthesis) for architectural and environmental attributes was HK$302.3/ft2 (5.8%) and HK$886.8/ft2 (28.2%), respectively, for RA and HK$1672.7/ft2 (31.9%) and HK$111.5/ft2 (3.5%) for COS. It was found that elasticity of substitution (ES) of environmental attributes contributed 3.4-13.3% of the property price, compared to 0.6-5.5% for architectural attributes.

Developing a simplified parameter for assessing view obstruction in high-rise high-density urban environment.

View is a key factor that influences property price. Previous studies represent view either by simple pictorial description of a scene, or by rather sophisticated mathematical methods. Both hinder proper allocation of a premium for different view obstruction levels for high-rise high-density urban environments. View obstruction level and the applicable premium are useful information for stakeholders of the property market for making optimum decisions. Accordingly, there is a need to develop a simple parameter for assessing view obstruction level. While view is difficult to define, reference is made to law cases which often settle view disputes by the extent of daylight obstruction. Shading mask is typically used to assess availability of daylight outside a residential unit and hence is an ideal parameter for assessing view obstruction. Computation of shading mask values (SMK) is a very complex task that needs meticulous site surveys, 3D drafting skills, and computer simulations. They are too effort intensive for stakeholders. This paper summarizes the relevant considerations and the case studies conducted to establish the average angle of unobstructed sky (θ) as a simple parameter to represent mean SMK for assessing view obstruction. Correlation analysis of mean SMK of 708 case study residential units determined by the detailed computer simulation method and the corresponding angle of unobstructed sky showed that the latter can be used to assess view obstruction adequately close to simulation predictions. Given average angle of unobstructed sky can easily be determined based on the geometrical primitives of a residential unit, this can enable future allocation of a premium for different view obstruction levels for stakeholders.

Cataloging and profiling genes expressed in Lentinula edodes fruiting body by massive cDNA pyrosequencing and LongSAGE.

This study investigated the molecular mechanism of the fruiting body development and sporulation in the cap of the Shiitake mushroom, Lentinula edodes. Although there has been much research into L. edodes, there remain significant gaps in our knowledge of how the species reproduces. In order to provide molecular resources and to understand the molecular mechanism of the fruiting body development in basidiomycete comprehensively, we searched for the genes which are important for fruiting body development and sporulation in the cap of mature fruiting body of L. edodes by using the whole-genome approach. Massive cDNA pyrosequencing was used to generate >7000 sequence contigs from mature fruiting bodies. We used Gene Ontology to categorize the contigs to form the catalog of genes expressed at the stage of the mature fruiting body. We also assigned the contigs into the KEGG pathways. The catalog of expressed genes indicates that the mature fruiting bodies (1) sense the external environment, (2) transmit signals to express genes through regulatory systems, (3) produce many proteins, (4) degrade unwanted proteins, (5) perform extensive biosynthesis, (6) generate energy, (7) regulate the internal environment, (8) transport molecules, (9) carry out cell division, and (10) differentiate and develop. After establishing the catalog of expressed genes in L. edodes, we used the LongSAGE approach to analyze the expression levels of genes found in mature fruiting bodies before (FB) and after (FBS) spores appeared. Gene-expression patterns according to GO categories were similar in these two stages. We have also successfully identified genes differentially expressed in FB and FBS. Fold-changes in expression levels of selected genes based on LongSAGE tag counts were similar to those obtained by real-time RT-PCR. The consistency between real-time RT-PCR and LongSAGE results indicates reliability of the LongSAGE results. Overall, this study provides valuable information on the fruiting processes of L. edodes through a combination of massive cDNA pyrosequencing and LongSAGE sequencing, and the knowledge thereby obtained may provide insight into the improvement of the yield of commercially grown Shiitake mushrooms.

Detection of animal viruses using nucleic acid sequence-based amplification (NASBA).

As seen in recent avian influenza outbreaks in Asia, prevention is the key to fighting infectious disease successfully. Efficient disease surveillance systems on the basis of molecular diagnostics will help monitor the emergence of viruses in the early stage and thus prompt containment measures can be in place to minimize disease spread. Here we describe and review molecular diagnostics focusing on nucleic acid sequence-based amplification (NASBA) technology in detecting viruses causing animal diseases, such as avian influenza, foot-and-mouth disease, and Newcastle disease. NASBA offers high sensitivity, specificity, accuracy, and speed of availability of results, and NASBA would be the most applicable molecular diagnostics for disease surveillance and control.

Characterization of a human cardiac gene which encodes for a LIM domain protein and is developmentally expressed in myocardial development.

A clone with high sequence homology to a rat muscle LIM protein has been isolated from a human fetal heart cDNA library. The isolated cDNA is 887 bp in length, with an open reading frame of 194 amino acid residues. Northern blot analysis revealed that it is predominantly expressed in fetal and neonatal hearts, with a low level of expression in adult heart and slow-twitch skeletal muscle (soleus). No detectable expression of this transcript was found in other tissues. Its cardiac expression and structural similarity to the rat homolog implied a regulatory role in human cardiac muscle. The biological property was confirmed by zinc binding assay, demonstrating its zinc-binding affinity. Homology of CLP to a rat muscle LIM protein and its predominantly differential expression in cardiac tissue imply its significant putative role in the development and growth of the human heart.

Identification of genes associated with myocardial development.

We are conducting a cDNA sequencing project using human heart cDNA libraries to study expression of genes in the human heart. From our human heart cDNA libraries, we have accumulated over 10,000 partial cDNA sequences (expressed sequence tags-ESTs) representing both the previously uncharacterized and known transcripts expressed in the human heart (Liew et al., 1994). Currently, we have applied dot blot hybridization as a rapid approach to determine the genes putatively involved in myocardial development. Differential expression patterns of gene transcripts represented by the cDNA clones can be revealed by comparing dot intensities on the autoradiographs, after hybridization with cDNA probes generated from neonatal and adult heart mRNAs, cDNA clones (1505) have been processed by dot blot hybridization, of which 924 and 581 represented novel and known transcripts respectively. Among the screened clones, about 1.4% were found to be differentially expressed during heart development. Further verification was accomplished by Northern blot analysis. By grouping the 581 clones corresponding to known transcripts, a study of the gene expression profile of the heart in the cardiovascular system can be achieved.

Analysis of expressed sequence tags from a fetal human heart cDNA library.

Single-pass sequencing of randomly selected cDNA clones to generate expressed sequence tags (ESTs) has been widely used to identify novel genes and to study gene expression in a variety of tissues. We have generated 2244 ESTs from a human fetal heart library (GenBank Accession Nos. R30692-30774 and R56965-58824), which we present in this report. Of these, 51.7% showed no homology to known genes or were similar only to other ESTs, while 48.4% demonstrated homology to known transcripts. A total of 764 ESTs corresponding to known genes were used to study gene expression patterns in the fetal heart and to analyze differences in these patterns from those observed in the adult heart. These analyses demonstrate the utility of ESTs and sequence-tagged clones in comparative studies of gene expression in the cardiovascular system, and they reveal that differential gene expression underlies the structural and functional characteristics of the developing heart.

A catalogue of genes in the cardiovascular system as identified by expressed sequence tags.

The heart, which is composed of all the cellular components of the circulatory system, is a representative organ for obtaining genes expressed in the cardiovascular system in normal and disease states. We used partial sequences of cDNA clones, or expressed sequence tags, to identify and tag genes expressed in this organ. More than 3500 partial sequences representing > 3000 cDNA clones have been obtained from either the 5' or 3' end of inserts derived from human heart cDNA libraries. Of 3132 cDNA clones analyzed by sequence similarity searching against the GenBank/EMBL data bases, 1485 (47.4%) were found to represent additional, previously undiscovered genes, whereas 267 clones were matched to human brain expressed sequence tags. Clones matching to known genes were catalogued according to their putative structural and cellular functions. cDNA probes from reverse-transcribed mRNAs of fetal and adult hearts were used to study differential expression of selected clones in cardiac development. Cataloguing genes expressed in the heart may provide insight into the genes involved in health and cardiovascular disease.