Nguyen Quoc

Daily time-step normalized difference vegetation index (NDVI) time series from satellite-derived (NOAA/AVHRR, SPOT/VEGETATION, TERRA/MODIS) and ground-based micrometeorological sensors were evaluated for a coniferous pine forest (Pinus sylvestris L.) located in Hyytiälä, Finland. Micrometeorology-based broadband NDVI was calculated from observed upward and downward photosynthetically activity radiation (PAR) and global radiation measurements. The composite satellite-derived NDVI time series were smoothed with a best index slope extraction method (BISE) and adjusted Fourier transform (AFT) in order to downscale from the compositing period to daily scale.The broadband and satellite-derived NDVIs were highly correlated during the main growth period (Julian days 90–270), but poorly correlated when the entire year was considered, i.e., large differences occurred during winter. High correlations were also found between the seasonal courses for broadband NDVI and daily air temperature. The analysis revealed that the onset of greenness in spring was consistently determined from broadband NDVI time series in different years, but that fluctuations in NDVI during the late season transition to winter dormancy prevented reliable prediction of the termination in physiological activity. Efforts to retrieve the same relationships during spring from satellite-derived NDVI failed.After comparing the smoothed time series from different NDVI determinations, we examined the relationship between NDVI, gross primary production (GPP) and FAPAR. An obvious exponential relationship is found between broadband NDVI and GPP (R2=0.72 for clear weather conditions; also detectable from the satellite sensors), while a linear relationship occurs between broadband NDVI and FAPAR (R2=0.79). FAPAR in relation to satellite-derived NDVI is best described with a logistic curve under clear weather conditions, but the level of correspondence is low (R2=0.53). Overall, broadband NDVI is a good index to describe physiological activity of the pine forest during certain periods, i.e. provides a means for obtaining other physiological parameters that are required by ecosystem models. However, during the late season, broadband NDVI estimated over the pine stand is influenced by more than vegetation physiological activity. Though satellite-derived NDVI is more difficult to link to GPP, it may still provide useful information under clear weather conditions. Satellite-derived NDVI remains our only choice for generalization in large-scale investigations. Thus, intensified examination of the influences of smoothing and downscaling of satellite-derived NDVI is inevitable.

Transformation of potato (Solanum tuberosum L.) with cysteine proteinase inhibitor (PI) genes represents a potential way of controlling the major insect pest Colorado potato beetle (CPB; Leptinotarsa decemlineata Say). The present study describes the Agrobacterium-mediated transformation of potato (cv. Kennebec) with an oryzacystatin I (OCI) cDNA clone linked to a CaMV 35S promoter. The transgenic plants accumulated active OCI in potato leaves, as demonstrated by the papain-inhibitory activity of transgenic plant leaf extracts. In addition to their anti-papain activity, the extracts also caused a partial but significant inhibition of CPB digestive proteinases, similar to that observed with pure inhibitors. Recombinant OCI did not alter the activity of the major potato leaf endogenous proteinases, which seemed to be of the serine-type. Therefore we suggest that the OCI cDNA can be used for the production of CPB-resistant transgenic potato plants without interfering with endogenous proteinases of these plants.

In this paper, we present the performance of fixed decode-and-forward cooperative networks with relay selection over independent but not identically distributed Nakagami-m fading channels, with integer values of the fading severity parameter m. Specifically, closed-form expressions for the symbol error probability and the outage probability are derived using the statistical characteristic of the signal-to-noise ratio. We also perform Monte-Carlo simulations to verify the analytical results.

BACKGROUND: Five times more Vietnamese-American women develop cervical cancer than white women. Few studies have examined whether community-based participatory research can effectively address Asian immigrants’ health problems. This article reports the preliminary evaluation of 1 such project. METHODS: A coalition of 11 organizations in Santa Clara County, California worked with university researchers to design and simultaneously implement a media education (ME) campaign and a lay health worker outreach (LHWO) program to increase Vietnamese-American women’s cervical cancer awareness, knowledge, and screening. Two agencies each recruited 10 lay health workers (LHWs), who, in turn, each recruited 20 women who were then randomized into 2 groups: 10 to LHWO+ME (n=200) and 10 to ME alone (n=200). LHWs organized meetings with women to increase their knowledge and to motivate them to obtain Pap tests. Participants completed pre- and post-intervention questionnaires. RESULTS: At post-intervention, significantly more LHWO+ME women understood that human papillomavirus and smoking cause cervical cancer. The number of women who had obtained a Pap test increased significantly among women in both LHWO+ME and ME groups, but substantially more in the LHWO+ME group. Significantly more LHWO+ME women said they intended to have a Pap test. CONCLUSIONS: Media education campaigns can increase Vietnamese women’s awareness of the importance of Pap tests, but lay health workers are more effective at encouraging women to actually obtain the tests. Lay health workers are effective because they use their cultural knowledge and social networks to create change. Researchers, community members, and community-based organizations can share expert knowledge and skills, and build one another’s capacities.

The use of oryzacystatins I and II, two cysteine proteinase inhibitors naturally produced in rice grains, represents an attractive way for the control of Coleoptera insect pests. The present study was done to analyze the inhibitory effect of recombinant oryzacystatins produced in Escherichia coli as fusion proteins against digestive proteinases of the major pest Colorado potato beetle (Leptinotarsa decemlineata Say). Both inhibitors had a significant effect on total proteolytic activity, but maximal inhibitions ranged from 20 to 80% for pHs varying from 5.0 to 7.0, respectively. This pH-dependent efficiency of plant cystatins was due to the selective inactivation of potato beetle cathepsin H, as demonstrated by the use of inhibitors with different specificities against cathepsins B and H. These results demonstrate the importance of having an adequate knowledge of insect proteinases specifically recognized by the inhibitors to be used in pest control strategies.

The concentrations of organochlorine pesticides and PCBs were determined in surface sediments and freshwater molluscs (Angulyagra sp.) from water canals in the region of Hanoi city. Results obtained show that the concentration of ΣDDT compounds in sediments range from 7 to 80 ng/g (dry weight) and from 6 to 864 ng/g (dry weight) in the soft tissues of molluscs. The concentrations of ΣDDTs were higher in populated sites and much lower in rural sites, indicating that the DDT has been used for mosquito control and not as a crop protection chemical. Hexachlocyclohexanes (HCHs) have also been widely used in the region but the current environmental concentrations are much lower than those of DDT's, which is due to the less persistence of those compounds. Polychlorinated biphenyls (PCBs) were measured, for example as aroclor 1254, in concentrations up to 40 ng/g (dry weight) and up to 76 ng/g (dry weight) in sediments and molluscs, respectively. Molluscs from water canals are a very popular food in the region. Taking into consideration the high DDT levels measured in these molluscs their consumption is worrisome and may expose the population to high levels of endocrine disrupting substances. Current PCB levels in sediments are lower than usually measured in industrialized countries. Therefore, PCB concentrations in aquatic molluscs are still also relatively low. These snails do not have enzyme ability to metabolize most of the CB congeners and, thus, are passive accumulators and a significant transfer pathway of CBs to consumers. Therefore, measures to phase out the use of these persistent and bioaccumulable chemicals should be adopted in order to prevent further environmental contamination.

An interative approach is proposed for the numerical analysis of elastic–plastic continua. This approach gives after convergence an implicit scheme of integration of the evolution problem, and is concerned with elastic-perfectly plastic materials and with hardening standard materials. Under a generalized assumption of positive hardening, the proof of convergence of the iterative solutions is given. Some numerical examples by the finite element method are also discussed.

Background.Previous research has shown that breast and cervical cancer screening rates are low among Vietnamese women.Methods.Over a 24-month period, we implemented a media-led community education campaign to promote recognition, intention, receipt, and currency of routine checkups, clinical breast examinations, mammograms, and Pap tests among Vietnamese-American women in Alameda and Santa Clara Counties in northern California. Women in Los Angeles and Orange Counties in southern California served as controls. To evaluate its impact, pretest telephone interviews were conducted of 451 randomly selected women in the intervention area and 482 women in the control area and posttest interviews with 454 and 422 women, respectively.Results.At posttest, after controlling for demographic differences in the surveyed populations, the odds ratios for the intervention effect were statistically significant for having heard of a general checkup, Paptest, and clinical breast examination (CBE); planning to have a checkup, Pap test, CBE, and mammogram; and having had a checkup and Pap test. The intervention had no effect on being up to date for any of the tests.Conclusions.A media-led education intervention succeeded in increasing recognition of and intention to undertake screening tests more than receipt of or currency with the tests.

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