MODELLING PRICE DYNAMICS IN THE HONG KONG PROPERTY MARKET

The property market in Hong Kong plays an important role in the political, social and economic life of this vibrant city. Understanding the dynamics of the market is essential to guide government policy making and investment decisions. Using data collected between 1993 and 2006, this study investigates the monthly returns, volatilities, and time-varying correlations in the residential, office, and retail property markets in Hong Kong. A vector autoregressive (VAR) model is used to examine the conditional mean, and a multivariate generalized autoregressive conditional heteroscedasticity (MGARCH) model is adopted to analyze the conditional variance. The dynamic conditional correlation (DCC) approach is utilized to specify the MGARCH model. All of the property types show strong auto- and cross-correlations, which indicates that the sectors relate to each other closely. All three sectors have higher volatilities when major political and economic events occur. The findings reveal the possibility of balancing investment portfolios between the three sectors in the Hong Kong property market. However, exposure to the residential sector may reduce the chance of investment diversification because of the higher correlation of this sector with the other property sectors.Return, volatility, dynamic conditional correlation.

Endophytic fungi associated with pioneer plants growing on the Athabasca oil sands

Fungal endophytes live inside plants without causing apparent symptoms of infection. All plant species surveyed thus far, including liverworts, mosses, seedless vascular plants, conifers, and angiosperms, harbor one or more endophytic fungi. Fungal endophytes can be divided into four groups including class 1, class 2, class 3 and class 4 endophytic fungi according to host range, colonization pattern, transmission, and ecological function. Class 2 fungal endophytes benefit their host by increasing environmental stress tolerance (i.e. water, temperature, salt) in a habitat-specific manner. In my study, class 2 fungal endophytes were studied from weedy plants growing in an environmentally stressed area: mine tailings from the Athabasca oil sands. This area is a vast hydrocarbon reserve in western Canada that supplies 10% of Canadian oil needs. Hydrocarbons are extracted from tar sands with hot water, alkali, and solvents. The tailing sands can later be remediated (by adding organic material and fertilizer) to establish new plant communities. Prior to remediation, tailing sands have extremely low content of organic carbon and available minerals, and are hydrophobic compared to unimpacted and remediated soils. Nevertheless, Taraxacum (dandelion) and Sonchus (sow-thistle) can colonize extracted tailing sands even prior to remediation. Preliminary results show that pioneer plants have similar fungal abundance as plants of unextracted treatments. Fungal endophytes were isolated from surface sterilized Taraxacum and Sonchus that had been growing upon unimpacted, remediated and extracted soil. Fungi isolated in this way included Alternaria, Tricoderma, Fusarium and an unidentified Perithecial Ascomycote. These endophytic fungi were used to inoculate tomato plants in a greenhouse trial to determine whether they confer stress tolerance to host plants, especially for drought and low mineral nutrition. Before exposing the tomato plants to environmental stresses, the specific endophytic fungal strains applied were successfully recovered from tomato plants originally inoculated with the same endophytic fungi. Although the other endophytic fungi turned out to be harmful to the tomato plants in the test, a Trichoderma spp. strain isolated from samples of extracted treatment appears to confer tolerance of tailing sands to the tomato plants. This Trichoderma spp. strain which we can call TSTh20-1 was molecularly identified as Trichoderma harzianum. Despite an identification to species, all strains of T. harzianum are not necessarily identical regarding strain-specific attributes. Using similar techniques described here, it is possible to isolate and potentially use beneficial class 2 endophytic fungal strains for the remediation process in the Athabasca oil sands or to assist plant growth in other high stress environments

Investor overconfidence and trading activity in the Asia Pacific REIT markets

Overconfidence is one of the most robust behavioral anomalies in financial markets. By attributing investment gains to their ability, investors become overconfident and trade aggressively in subsequent periods. Evidence from stock markets shows that overconfidence leads to excessive trading and, subsequently, inferior investment performance. However, studies on overconfidence effect are lacking in the real estate sector, which is particularly true for Asia Pacific real estate investment trust (REIT) markets. Thus, this study examines the overconfidence effect in six Asia Pacific REIT markets, namely, Australia, Hong Kong, Japan, Singapore, South Korea, and Taiwan. The study finds that the overconfidence effect is more conspicuous during market boom periods or in inefficient market conditions. In addition, simulation analysis demonstrates that overconfidence could lead to rather large volumes of excessive trading activities in certain markets. Findings are robust across the alternative measures of control variables. Moreover, the policy implications of the research are also discussed.ESR

A randomized algorithm for the QR decomposition-based approximate SVD

Matrix decomposition is a very important mathematical tool in numerical linear algebra for data processing. In this paper, we introduce a new randomized matrix decomposition algorithm, which is called randomized approximate SVD based on Qatar Riyal decomposition (RCSVD-QR). Our method utilize random sampling and the OR decomposition to address a serious bottlenck associated with classical SVD. RCSVD-QR gives satisfactory convergence speed as well as accuracy as compared to those state-of-the-art algorithms. In addition, we provides an estimate for the expected approximation error in Frobenius norm. Numerical experiments verify these claims.Comment: 6 pages,6 figure

Impacts of Users’ Extra-Role Behaviors on Bright Internet Policy Adoption

Cyberspace security has been one top issue for a society. The Bright Internet (BI) based on the five principles offers a viable solution. The adoption of BI is important to the implementation of BI. A majority of the previous studies have mainly focused on access-policy violations and compliance in the past decades, while the extra-role behaviors have obtained insufficient attentions. Based on the theories of social control and accountability, this study examines the impacts of extra-role behaviors on BI policy adoption. The research findings have implications for future research and practice

JWST CEERS & JADES Active Galaxies at z = 4-7 Violate the Local M∙−M⋆M_\bullet-M_\star Relation at >3σ>3\sigma: Implications for Low-Mass Black Holes and Seeding Models

JWST is revolutionizing our understanding of the high-z Universe by expanding the black hole horizon, looking farther and to smaller masses, and revealing the stellar light of their hosts. New detections of high-z systems offer unprecedented insights into the formation of the first black holes and their early co-evolution with galaxies. By examining JWST galaxies at z=4-7 that host H$\alpha$-detected black holes, we investigate (i) the high-z $M_\bullet-M_\star$ relation and (ii) the black hole mass distribution, especially in its low-mass range ($M_\bullet\lesssim10^{6.5} M_\odot$). With a detailed statistical analysis, our findings conclusively reveal a high-z $M_\bullet-M_\star$ relation that deviates at $>3\sigma$ confidence level from the local relation: $\log(M_\bullet/M_\odot) = -2.38^{+0.82}_{-0.83}+1.06^{+0.09}_{-0.09}\log(M_\star/M_\odot)$. Black holes are overmassive by $\sim10-100\times$ compared to their local counterparts in similar galactic hosts. This fact is not due to a selection effect in surveys. Moreover, our analysis predicts the possibility of detecting in high-z JWST surveys $5-18\times$ more black holes with $M_\bullet\lesssim10^{6.5} M_\odot$, and $10-30\times$ more with $M_\bullet \lesssim 10^{8.5} M_\odot$, compared to local relation's predictions. The lighter black holes preferentially occupy galaxies with a stellar mass of $\sim 10^{7.5}-10^8 M_\odot$. We have yet to detect these sources because (i) they may be inactive (duty cycles 1%-10%), (ii) the host overshines the AGN, or (iii) the AGN is obscured and not immediately recognizable by line diagnostics. A search of low-mass black holes in existing JWST surveys will further test the $M_\bullet-M_\star$ relation. Current JWST fields represent a treasure trove of black hole systems at z=4-7; their detection will provide crucial insights into their early evolution and co-evolution with their galactic hosts.Comment: Submitted for publication in The Astrophysical Journal Letters. 13 pages, 5 figure

Study on failure warning of tool magazine and automatic tool changer

Tool magazine and automatic tool changer (ATC) is used to store and change tools in a machining center, which plays an important role in automatic manufacturing. Therefore, the stability and reliability of tool magazine and ATC is very important to a machining center. Failures of tool magazine and ATC would increase ramp-up repair time and repair cost. So early warning system of failures for tool magazine and ATC becomes a research hotspot. The main vibration signals of tool magazine and ATC would occur obviously when the tool arm grasps a tool holder, draws a tool holder out of a tool into spindle or tool pocket and inserts a tool holder into spindle or tool pocket. To predict failures of tool magazine and ATC and improve the availability of machining center, a vibration test procedure and calculation method of vibration signal threshold of pull nails looseness which can lead to tool falling failures are proposed based on the vibration detection theory. Then, the vibration signals of tool changing are analyzed and the relationship between the maximum amplitude of vibration signals and the looseness severity of pull nails is also illustrated. The final experiment results show that the tool falling failure warning method is feasible to reduce the failures of tool magazine and ATC through the early warning system based on the threshold of vibration signals

Stable isotopes and hydrogeochemical evolutions of groundwater from a typical seismic fault zone in the Mt. Lushan region, Eastern China

We analyzed the major chemical components, hydrogen (δD) and oxygen isotopes (δ18O), and tritium activity in groundwater from Jiujiang well number 2 (JJ2) as well as atmospheric precipitation and water from the Maweishui spring and Tianhuajing reservoir in the Mt. Lushan region, Eastern China. The results show that the water in JJ2 is of the HCO3-Ca·Mg type, with ionic components mainly arising from calcite and dolomite mineral dissolution. According to the δD and δ18O data, the groundwater of JJ2 mainly comes from atmospheric precipitation, and the recharge elevation is 554 m. Results for tritium activity indicate that JJ2 is fed by both an ancient water supply and a new water supply within a period of 10 years. These results demonstrate that JJ2 has characteristics of both shallow and deep circulating water, which implies that aquifers involving two different recharge sources rise to the well surface via different circulation paths. That is exactly why JJ2 is tectonically sensitive and could display a remarkable gas radon anomaly before the Ruichang-Yangxin ML 5.0 earthquake in 2011. Our results also indicate that ascertaining the hydrological characteristics and cycling process of groundwater are crucial for understanding the earthquake anomalies and judging whether a seismic groundwater monitoring well is reliable or not

SDSS J013127.34−-032100.1: A newly discovered radio-loud quasar at z=5.18z=5.18 with extremely high luminosity

Only very few z>5 quasars discovered to date are radio-loud, with a radio-to-optical flux ratio (radio-loudness parameter) higher than 10. Here we report the discovery of an optically luminous radio-loud quasar, SDSS J013127.34-032100.1 (J0131-0321 in short), at z=5.18+-0.01 using the Lijiang 2.4m and Magellan telescopes. J0131-0321 has a spectral energy distribution consistent with that of radio-loud quasars. With an i-band magnitude of 18.47 and radio flux density of 33 mJy, its radio-loudness parameter is ~100. The optical and near-infrared spectra taken by Magellan enable us to estimate its bolometric luminosity to be L_bol ~ 1.1E48 erg/s, approximately 4.5 times greater than that of the most distant quasar known to date. The black hole mass of J0131-0321 is estimated to be 2.7E9 solar masses, with an uncertainty up to 0.4 dex. Detailed physical properties of this high-redshift, radio-loud, potentially super-Eddington quasar can be probed in the future with more dedicated and intensive follow-up observations using multi-wavelength facilities.Comment: 5 pages, 3 figures, accepted to ApJ

Horizontally Acquired Polysaccharide-Synthetic Gene Cluster From Weissella cibaria Boosts the Probiotic Property of Lactiplantibacillus plantarum

Lactiplantibacillus plantarum are probiotic bacteria, maintaining the integrity of the gastrointestinal epithelial barrier, and preventing the infection of pathogenic bacteria. Exopolysaccharides (EPSs) are often involved in the probiotic property of L. plantarum. Here, we identified a new EPS-synthetic gene cluster, cpsWc, carrying 13 genes, laid on a large plasmid in a well-characterized probiotic L. plantarum strain LTC-113. The cpsWc gene cluster was horizontally acquired from Weissella cibaria, enhancing the biofilm formation ability of the host strain and its tolerance to harsh environmental stresses, including heat, acid, and bile. Transfer of cpsWc also conferred the probiotic properties to other L. plantarum strains. Moreover, cpsWc strengthened the adhesion of LTC-113 to intestinal epithelial cells. Both the cpsWc-carrying LTC-113 and its EPSs per se effectively attenuated the LPS-induced pro-inflammatory effect of intestinal epithelial cells, and inhibited the adhesion of pathogenic bacteria, such as S. typhimurium and E. coli by exclusion and competition. The newly identified cpsWc gene cluster emphasized the contribution of mobile EPS-synthetic element on the probiotic activity of L. plantarum, and shed a light on the engineering of probiotic bacteria