The weak Lefschetz property of artinian algebras associated to paths and cycles

Given a base field $\Bbbk$ of characteristic zero, for each graph $G$, we associate the artinian algebra $A(G)$ defined by the edge ideal of $G$ and the squares of the variables. We study the weak Lefschetz property of $A(G)$. We classify some classes of graphs with relatively few edges, including paths and cycles, such that its associated artinian ring has the weak Lefschetz property.Comment: 21 pages. Comments are welcome

STUDY ON ITO THIN FILMS PREPARED BY MULTI-ANNEALING TECHNIQUE

Indium tin oxide (ITO) thin films have been successfully prepared by a solution process followed by a multi-annealing method. In this study, we focus on the use of multi-annealing method, for which each layer was annealed at a suitable temperature, instead of a conventional annealing way, by means of a rapid thermal annealing system, in order to improve the film quality. The crystalline structure and surface morphology of the ITO thin films were investigated by using X-ray diffraction (XRD) spectrometer, atomic force microscope (AFM) and scanning electron microscope (SEM). It has been obtained that all of ITO films exhibit a single phase with (222)- and (440)-preferred orientations. The AFM and SEM observations show that the particle size of ITO films was about 10 nm and the ITO film thickness was 180 nm, respectively. In sequence, the electrical properties of ITO thin films were evaluated by using four-point probe and Hall effect measurement methods, and the optical properties were investigated by UV/VIS spectrometer. The results show that the best ITO films have electrical resistivity of 2.6 × 10-3 Ω.cm and transparency higher than 90 %, which strongly supports to the application of electrode in solar cell, LED or transistor devices from viewpoints of low-cost production and low-energy consumption

IMPACT OF RISK FACTORS ON BUSINESS RESULTS OF LIFE INSURANCE PRODUCTS IN INSURANCE COMPANIES IN HUE CITY

Abstract: On the basis of the leveraging Monte Carlo simulation method and @Risk – a risk analysis software, this study aims to identify and analyse the impacts of the potential risk factors on business results of life insurance products in the insurance companies in Hue city. Both the qualitative and quantitative method is applied. Data were collected from interviewing the leaders, financial managers and senior consultants at four most representative life insurance companies in the area, namely Bao Viet life insurance, Prudential, AIA, and PCI Sun Life using the DELPHI technique. The following findings are found. Firstly, besides the identified events, 10 other types of risks could affect the business results of life insurers. Secondly, these types of risks have varied frequencies and levels of impact on the three studied variables of the simulation model. Finally, the risk of rumours and the risk of new competitors appear to be the most significant dangers to the expected profits of life insurance companies.Keywords: Monte Carlo simulation, @Risk, Delphi technique, life insuranc

Productivity, net returns and efficiency: land and market reform in Vietnamese rice production

Extensive land and market reform in Vietnam has resulted in dramatic increases in rice output over the past thirty years. The land and market reforms in agriculture were pervasive, moving the system of rice production from commune-based public ownership and control to one with effective private property rights over land and farm assets, competitive domestic markets and individual decision making over a wide range of agricultural activities. The effect of this reform period and beyond is detailed with measures of total factor productivity (TFP), terms of trade and net returns in rice production in Vietnam from 1985 to 2006. Results show that TFP rises considerably in the major rice growing areas (the Mekong and Red River Delta areas) during the early years of reform, and beyond, but also that there is clear evidence of a productivity “slow-down” since 2000. The differences over time and by region speak directly to existing land use regulations and practices, suggesting calls for further land and market reform. To illustrate this, additional frontier and efficiency model estimates detail the effects of remaining institutional and policy constraints, including existing restrictions on land consolidation and conversion and poorly developed markets for land and capital. Estimates show that larger and less land-fragmented farms, farms in the major rice growing areas, and those farms that are better irrigated, have a greater proportion of capital per unit of cultivated land, a clear property right or land use certificate and access to agricultural extension services are more efficient

Nucleotide variation at the methionine synthase locus in an endangered tree species, Fokienia hodginsii (Cupressaceae) in Vietnam

Nucleotide variation at the methionine synthase (MetE) locus within and among populations of an endangered forest tree Fokienia hodginsii in Vietnam was investigated in the present study. A total of 12 populations were sampled across Vietnam. The length of the sequenced locus varied from 1567 to 1559 bp. A total of 42 polymorphic sites were detected among samples. Overall, nucleotide diversity was estimated to be 0.00499 and 0.00692 at the total (ðtot) and silent sites (ðsilent) in the pool, respectively. Nucleotide diversity within populations varied from 0.00300 to 0.00521 at the total and 0.00357 to 0.00666 at silent sites. The estimates of nucleotide diversity were lower in the 4 populations located in central and southern Vietnam (0.00300 to 0.00380) in comparison with the northern populations (ranging from 0.00399 to 0.00543). Overall estimates of genetic differentiation among 12 populations were low (FST = 0.093 and KST* = 0.078), even though both values were highly significant (P < 0.001). Pairwise analysis among 12 populations showed significant genetic differentiation as evaluated by FST and Snn but not significant as evaluated by KST*. Analysis of genetic clustering using BAPS provided the best support for all 144 sequences belonging to the same genetic cluster. The implication of the results revealed in this study in the genetic conservation of F. hodginsii was discussed.Key words: Population genetics, conservation, forest, methionine synthase (MetE), structure