Nguyen Hien - Academia.edu (original) (raw)
Papers by Nguyen Hien
Experience and observation as a learners and teachers of English as a foreign language (EFL) conv... more Experience and observation as a learners and teachers of English as a foreign language (EFL) convince us that memorization seems to be one of the learning methods that helps EFL students learn and use the English language, provided that memorization is used appropriately to help learners to internalise what they have learned to apply in actual communication. On the other hand, some teachers argue that memorization and communication cannot coexist in an academic environment. This controversy inspired this investigation into whether memorization is accepted as a strategy in the process of learning EFL in EFL students' and teachers' perspectives, and if so, what role memorization plays. The research aims to identify learners' and teachers' beliefs about learning EFL in relation to memorization as well as to provide an insight into the possible effectiveness of memorization. Gleaned from questionnaires and interviews, the data were analysed by using ethnographic methods. Memorization is a mental process, so the choice of qualitative method as the main data collection and analysis tool is appropriate, but to carry out qualitative research in Vietnam is undeniably challenging. Apart from common difficulties such as time constraints, members of powerful research committees at Vietnamese universities--such as the one where the data were gathered--generate many doubts. Nonetheless, it was found that both teachers and learners differentiated between "good" and "bad" memorization in terms of a specific, commonly used task in Vietnamese universities, giving speeches in English.
Tropical doctor, 2005
The objective of this cross-sectional study was to evaluate the association between prenatal care... more The objective of this cross-sectional study was to evaluate the association between prenatal care visits and infant birthweight among ethnic minority mothers in the mountainous Bac Kan province. This was done by comparing the frequency and timing of first prenatal care visit of 32 mothers with low birthweight (LBW) infants and 32 mothers with normal birthweight (NBW) infants. During pregnancy, mothers of NBW infants underwent 3.4+/-1 (mean) prenatal care visits and mothers of LBW infants 2.8+/-0.9 (P = 0.02). Mothers of NBW infants underwent their first prenatal care visit at 13.1+/-5.7 weeks of gestation, one week earlier than mothers of LBW infants. The frequency of prenatal care visit are probably associated with a decreased risk of LBW among ethnic minority mothers in Bac Kan province.
Pediatrics international : official journal of the Japan Pediatric Society, 2007
Birthweight and length have been reported to be important determinants of infant growth and futur... more Birthweight and length have been reported to be important determinants of infant growth and future nutritional status. The study aims to describe the weight and length growth patterns during the first year of life of low-birthweight (LBW) ethnic minority infants in the mountainous province Backan, Vietnam. A total of 64 LBW and normal birthweight infants of ethnic minority mothers were recruited from 2001 to 2002 into a prospective cohort study. The weight and length of infants were measured monthly for 1 year. Data on nutritional status and feeding practices of the infants were collected from monthly health records and face-to-face interviews with mothers while their infants were 6 and 12 months of age. Most of the increase in weight, length and catch-up to the 10th percentile for LBW infants occurred during the first 3 and 6 months for boys and for girls, respectively. After these ages, the mean weight and length diverged from National Center for Health Statistics (NCHS) reference curves to below the 10th percentile. LBW infants' weight-for-age z-scores was below the NCHS standard at birth (-2.16 SD), caught up after birth, became sustainable by 4 months, fell rapidly from the sixth month, then decreased to -2 SD at 12 months of age. LBW infants' length-for-age z-scores increased in the first month after birth, decreased in the second month and sharply increased again until 5 months of age before decreasing. For LBW infants, it is difficult to achieve the same weight or length curves at 12 months of age as the NCHS standard.
Drug and alcohol dependence, 2014
Background: The interrelationship between the well-being of injecting drug users (IDUs) and their... more Background: The interrelationship between the well-being of injecting drug users (IDUs) and their family environment has been widely documented. However, few intervention programs have addressed the needs of both IDUs and their family members. Methods: This study describes a randomized intervention pilot targeting 83 IDUs and 83 of their family members from four communes in Phú Tho . province, Vietnam. The IDUs and family members in the intervention condition received multiple group sessions, with the intent to improve psychological wellbeing and family relationships. The intervention outcomes (depressive symptoms and family relations) were evaluated at baseline, 3-month and 6-month follow-up assessments. Results: Depressive symptoms and family relations reported by IDUs were found to be correlated to those reported by their family members. Overall, significant intervention effects on depressive symptoms and family relations were observed for both IDUs and family members. A similar improvement pattern in family relations emerged for both the IDU and family member samples, although the intervention effect of reducing depressive symptoms was more sustainable for family members at the 6-month assessment when compared to the IDU sample. Conclusion: The intervention pilot addressed challenges faced by IDUs and their family members and revealed correlated outcomes for the two groups. Findings suggest a vital need to include family members in future drug prevention and harm reduction intervention efforts.
Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors, 2014
Family plays an important role in the lives of injecting drug users (IDUs) in Vietnam. This study... more Family plays an important role in the lives of injecting drug users (IDUs) in Vietnam. This study examined the preliminary outcomes of an intervention targeting IDUs and their family members in Vietnam. Eighty-three families, including 83 IDUs and 83 family members, were recruited from 4 communes in Phú Th ខo Province, Vietnam. The 4 communes were randomized to either an intervention condition or a standard care condition. The IDUs and their family members in the intervention condition completed 4 group sessions, with the aims to improve their mental health and family relations and to promote positive behavioral change. The intervention effect was evaluated at baseline and 3-and 6-month follow-up assessments. A significant reduction in depressive symptoms and improvement in family functioning were reported for IDUs in the intervention group compared with those in the standard care group. The family members in the intervention group reported better coping skills at 3 months, fewer depressive symptoms at 6 months, and improved family function at both 3 and 6 months compared with those in the standard care group. However, no significant intervention effect was observed for IDUs in terms of drug-using behavior. This study demonstrates the feasibility and preliminary outcomes of an intervention that simultaneously targets IDUs and their family members in Vietnam. Study findings highlight the importance of including family members and enhancing their role in drug use intervention efforts.
The Journal of infection, 2014
Influenza household transmission studies are required to guide prevention strategies but most pas... more Influenza household transmission studies are required to guide prevention strategies but most passively recruit index cases that seek healthcare. We investigated A(H1N1)pdm09 transmission in a household-based cohort during 2009. Health-workers visited 270 households weekly, and collected swabs from influenza-like-illness cases. If A(H1N1)pdm09 was RT-PCR-confirmed, all household members had symptoms assessed and swabs collected daily for 10-15 days. Viral RNA was quantified and sequenced and serology performed on pre-pandemic sera. Index cases were detected in 20 households containing 81 people. 98.5% lacked A(H1N1)pdm09 neutralizing antibodies in pre-pandemic sera. Eleven (18.6%, 95% CI 10.7-30.4%) of 59 contacts were infected. Virus genetic diversity within households was negligible and less than between households. Index and secondary cases were distributed between mothers, daughters and sons, and had similar virus-RNA shedding and symptom dynamics. Fathers were rarely infected. Five secondary cases (45%) had no apparent symptoms and three shed virus before symptoms. Secondary infection was associated with index case wet cough (OR 1.56, 95% CI 1.22-1.99). In this cohort of A(H1N1)pdm09 susceptible persons, virus sequencing was capable of discriminating household from community transmission. Household transmission involved mothers and children but rarely fathers. Asymptomatic or pre-symptomatic shedding was common.
The Journal of infection, 2015
Journal of Infection (2014) xx, 1e10 Please cite this article in press as: Fox A, et al., Hemaggl... more Journal of Infection (2014) xx, 1e10 Please cite this article in press as: Fox A, et al., Hemagglutination inhibiting antibodies and protection against seasonal and pandemic influenza infection, J Infect (2014), http://dx.
2011 IEEE Congress of Evolutionary Computation (CEC), 2011
In this paper, we investigate the impact of a lay- ered learning approach with incremental sampli... more In this paper, we investigate the impact of a lay- ered learning approach with incremental sampling on Genetic Programming (GP). The new system, called GPLL, is tested and compared with standard GP on twelve symbolic regression problems. While GPLL does not differ from standard GP on univariate target functions, it has better training efficiency on problems with bivariate targets. This
Lecture Notes in Computer Science, 2010
This paper examines the impact of semantic control on the ability of Genetic Programming (GP) to ... more This paper examines the impact of semantic control on the ability of Genetic Programming (GP) to generalise via a semantic based crossover operator (Semantic Similarity based Crossover - SSC). The use of validation sets is also investigated for both standard crossover and SSC. All GP systems are tested on a number of real-valued symbolic regression problems. The experimental results show
There are widespread attempts by scientists and commercial producers to improve yields of crop pl... more There are widespread attempts by scientists and commercial producers to improve yields of crop plants with plant growth-promoting rhizobacteria (PGPR). Importantly, there is now statistically significant evidence (e.g., Nguyen et al., 2003) that benefits from inoculation can be obtained under field conditions, so reducing the need for high inputs of nutrients particularly nitrogen and providing significant economic benefits to farmers. We have advanced the hypothesis that diazotrophs are specially adapted to this PGPR role (Kennedy et al., 2004), because their ability to grow in conditions of high C:N ratios. However, such diazotrophic PGPRs do not yet provide a technology recognised as reliable enough to justify their application to crops such as rice and wheat on a global scale.
Journal of Plant Nutrition, 2011
Field experiments during two successive rainy seasons were conducted in southern Vietnam to evalu... more Field experiments during two successive rainy seasons were conducted in southern Vietnam to evaluate the effects of a commercial inoculant biofertilizer (‘BioGro’) and fused magnesium phosphate (FMP) fertilizer on yield and nitrogen (N) and phosphorus (P) nutrition of rice. Inoculation with BioGro containing a pseudomonad, two bacilli and a soil yeast significantly increased grain yield in the second season and straw yield in both seasons by 3–5%. The FMP fertilizer significantly increased grain yield from 1.72–2.33 t ha−1 to 2.99–3.58 t ha−1 along with total N and P accumulation at all rates in both cropping seasons. In the first season the difference in grain yield between BioGro treated and untreated plots was marginal but in the second season BioGro out-yielded the control at all the rates of added P. Overall, BioGro application did not compensate for low P fertilizer application to the same extent previously demonstrated for low N fertilizer applications.
PLOS Neglected Tropical Diseases, 2011
Background: An estimated 2.4 billion people live in areas at risk of dengue transmission, therefo... more Background: An estimated 2.4 billion people live in areas at risk of dengue transmission, therefore the factors determining the establishment of endemic dengue in areas where transmission suitability is marginal is of considerable importance. Hanoi, Vietnam is such an area, and following a large dengue outbreak in 2009, we set out to determine if dengue is emerging in Hanoi.
To evaluate risk factors for human infection with influenza A subtype H5N1, we performed a matche... more To evaluate risk factors for human infection with influenza A subtype H5N1, we performed a matched casecontrol study in Vietnam. We enrolled 28 case-patients who had laboratory-confirmed H5N1 infection during 2004 and 106 age-, sex-, and location-matched control-respondents. Data were analyzed by matched-pair analysis and multivariate conditional logistic regression. Factors that were independently associated with H5N1 infection were preparing sick or dead poultry for consumption <7 days before illness onset (matched odds ratio [OR] 8.99, 95% confidence interval [CI] 0.98-81.99, p = 0.05), having sick or dead poultry in the household <7 days before illness onset (matched OR 4.94, 95% CI 1.21-20.20, p = 0.03), and lack of an indoor water source (matched OR 6.46, 95% CI 1.20-34.81, p = 0.03). Factors not significantly associated with infection were raising healthy poultry, preparing healthy poultry for consumption, and exposure to persons with an acute respiratory illness.
PLOS One, 2011
Background: The spread of infectious diseases from person to person is determined by the frequenc... more Background: The spread of infectious diseases from person to person is determined by the frequency and nature of contacts between infected and susceptible members of the population. Although there is a long history of using mathematical models to understand these transmission dynamics, there are still remarkably little empirical data on contact behaviors with which to parameterize these models. Even starker is the almost complete absence of data from developing countries. We sought to address this knowledge gap by conducting a household based social contact diary in rural Vietnam.
Clinical ophthalmology (Auckland, N.Z.), 2014
Experience and observation as a learners and teachers of English as a foreign language (EFL) conv... more Experience and observation as a learners and teachers of English as a foreign language (EFL) convince us that memorization seems to be one of the learning methods that helps EFL students learn and use the English language, provided that memorization is used appropriately to help learners to internalise what they have learned to apply in actual communication. On the other hand, some teachers argue that memorization and communication cannot coexist in an academic environment. This controversy inspired this investigation into whether memorization is accepted as a strategy in the process of learning EFL in EFL students' and teachers' perspectives, and if so, what role memorization plays. The research aims to identify learners' and teachers' beliefs about learning EFL in relation to memorization as well as to provide an insight into the possible effectiveness of memorization. Gleaned from questionnaires and interviews, the data were analysed by using ethnographic methods. Memorization is a mental process, so the choice of qualitative method as the main data collection and analysis tool is appropriate, but to carry out qualitative research in Vietnam is undeniably challenging. Apart from common difficulties such as time constraints, members of powerful research committees at Vietnamese universities--such as the one where the data were gathered--generate many doubts. Nonetheless, it was found that both teachers and learners differentiated between "good" and "bad" memorization in terms of a specific, commonly used task in Vietnamese universities, giving speeches in English.
Tropical doctor, 2005
The objective of this cross-sectional study was to evaluate the association between prenatal care... more The objective of this cross-sectional study was to evaluate the association between prenatal care visits and infant birthweight among ethnic minority mothers in the mountainous Bac Kan province. This was done by comparing the frequency and timing of first prenatal care visit of 32 mothers with low birthweight (LBW) infants and 32 mothers with normal birthweight (NBW) infants. During pregnancy, mothers of NBW infants underwent 3.4+/-1 (mean) prenatal care visits and mothers of LBW infants 2.8+/-0.9 (P = 0.02). Mothers of NBW infants underwent their first prenatal care visit at 13.1+/-5.7 weeks of gestation, one week earlier than mothers of LBW infants. The frequency of prenatal care visit are probably associated with a decreased risk of LBW among ethnic minority mothers in Bac Kan province.
Pediatrics international : official journal of the Japan Pediatric Society, 2007
Birthweight and length have been reported to be important determinants of infant growth and futur... more Birthweight and length have been reported to be important determinants of infant growth and future nutritional status. The study aims to describe the weight and length growth patterns during the first year of life of low-birthweight (LBW) ethnic minority infants in the mountainous province Backan, Vietnam. A total of 64 LBW and normal birthweight infants of ethnic minority mothers were recruited from 2001 to 2002 into a prospective cohort study. The weight and length of infants were measured monthly for 1 year. Data on nutritional status and feeding practices of the infants were collected from monthly health records and face-to-face interviews with mothers while their infants were 6 and 12 months of age. Most of the increase in weight, length and catch-up to the 10th percentile for LBW infants occurred during the first 3 and 6 months for boys and for girls, respectively. After these ages, the mean weight and length diverged from National Center for Health Statistics (NCHS) reference curves to below the 10th percentile. LBW infants&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; weight-for-age z-scores was below the NCHS standard at birth (-2.16 SD), caught up after birth, became sustainable by 4 months, fell rapidly from the sixth month, then decreased to -2 SD at 12 months of age. LBW infants&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; length-for-age z-scores increased in the first month after birth, decreased in the second month and sharply increased again until 5 months of age before decreasing. For LBW infants, it is difficult to achieve the same weight or length curves at 12 months of age as the NCHS standard.
Drug and alcohol dependence, 2014
Background: The interrelationship between the well-being of injecting drug users (IDUs) and their... more Background: The interrelationship between the well-being of injecting drug users (IDUs) and their family environment has been widely documented. However, few intervention programs have addressed the needs of both IDUs and their family members. Methods: This study describes a randomized intervention pilot targeting 83 IDUs and 83 of their family members from four communes in Phú Tho . province, Vietnam. The IDUs and family members in the intervention condition received multiple group sessions, with the intent to improve psychological wellbeing and family relationships. The intervention outcomes (depressive symptoms and family relations) were evaluated at baseline, 3-month and 6-month follow-up assessments. Results: Depressive symptoms and family relations reported by IDUs were found to be correlated to those reported by their family members. Overall, significant intervention effects on depressive symptoms and family relations were observed for both IDUs and family members. A similar improvement pattern in family relations emerged for both the IDU and family member samples, although the intervention effect of reducing depressive symptoms was more sustainable for family members at the 6-month assessment when compared to the IDU sample. Conclusion: The intervention pilot addressed challenges faced by IDUs and their family members and revealed correlated outcomes for the two groups. Findings suggest a vital need to include family members in future drug prevention and harm reduction intervention efforts.
Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors, 2014
Family plays an important role in the lives of injecting drug users (IDUs) in Vietnam. This study... more Family plays an important role in the lives of injecting drug users (IDUs) in Vietnam. This study examined the preliminary outcomes of an intervention targeting IDUs and their family members in Vietnam. Eighty-three families, including 83 IDUs and 83 family members, were recruited from 4 communes in Phú Th ខo Province, Vietnam. The 4 communes were randomized to either an intervention condition or a standard care condition. The IDUs and their family members in the intervention condition completed 4 group sessions, with the aims to improve their mental health and family relations and to promote positive behavioral change. The intervention effect was evaluated at baseline and 3-and 6-month follow-up assessments. A significant reduction in depressive symptoms and improvement in family functioning were reported for IDUs in the intervention group compared with those in the standard care group. The family members in the intervention group reported better coping skills at 3 months, fewer depressive symptoms at 6 months, and improved family function at both 3 and 6 months compared with those in the standard care group. However, no significant intervention effect was observed for IDUs in terms of drug-using behavior. This study demonstrates the feasibility and preliminary outcomes of an intervention that simultaneously targets IDUs and their family members in Vietnam. Study findings highlight the importance of including family members and enhancing their role in drug use intervention efforts.
The Journal of infection, 2014
Influenza household transmission studies are required to guide prevention strategies but most pas... more Influenza household transmission studies are required to guide prevention strategies but most passively recruit index cases that seek healthcare. We investigated A(H1N1)pdm09 transmission in a household-based cohort during 2009. Health-workers visited 270 households weekly, and collected swabs from influenza-like-illness cases. If A(H1N1)pdm09 was RT-PCR-confirmed, all household members had symptoms assessed and swabs collected daily for 10-15 days. Viral RNA was quantified and sequenced and serology performed on pre-pandemic sera. Index cases were detected in 20 households containing 81 people. 98.5% lacked A(H1N1)pdm09 neutralizing antibodies in pre-pandemic sera. Eleven (18.6%, 95% CI 10.7-30.4%) of 59 contacts were infected. Virus genetic diversity within households was negligible and less than between households. Index and secondary cases were distributed between mothers, daughters and sons, and had similar virus-RNA shedding and symptom dynamics. Fathers were rarely infected. Five secondary cases (45%) had no apparent symptoms and three shed virus before symptoms. Secondary infection was associated with index case wet cough (OR 1.56, 95% CI 1.22-1.99). In this cohort of A(H1N1)pdm09 susceptible persons, virus sequencing was capable of discriminating household from community transmission. Household transmission involved mothers and children but rarely fathers. Asymptomatic or pre-symptomatic shedding was common.
The Journal of infection, 2015
Journal of Infection (2014) xx, 1e10 Please cite this article in press as: Fox A, et al., Hemaggl... more Journal of Infection (2014) xx, 1e10 Please cite this article in press as: Fox A, et al., Hemagglutination inhibiting antibodies and protection against seasonal and pandemic influenza infection, J Infect (2014), http://dx.
2011 IEEE Congress of Evolutionary Computation (CEC), 2011
In this paper, we investigate the impact of a lay- ered learning approach with incremental sampli... more In this paper, we investigate the impact of a lay- ered learning approach with incremental sampling on Genetic Programming (GP). The new system, called GPLL, is tested and compared with standard GP on twelve symbolic regression problems. While GPLL does not differ from standard GP on univariate target functions, it has better training efficiency on problems with bivariate targets. This
Lecture Notes in Computer Science, 2010
This paper examines the impact of semantic control on the ability of Genetic Programming (GP) to ... more This paper examines the impact of semantic control on the ability of Genetic Programming (GP) to generalise via a semantic based crossover operator (Semantic Similarity based Crossover - SSC). The use of validation sets is also investigated for both standard crossover and SSC. All GP systems are tested on a number of real-valued symbolic regression problems. The experimental results show
There are widespread attempts by scientists and commercial producers to improve yields of crop pl... more There are widespread attempts by scientists and commercial producers to improve yields of crop plants with plant growth-promoting rhizobacteria (PGPR). Importantly, there is now statistically significant evidence (e.g., Nguyen et al., 2003) that benefits from inoculation can be obtained under field conditions, so reducing the need for high inputs of nutrients particularly nitrogen and providing significant economic benefits to farmers. We have advanced the hypothesis that diazotrophs are specially adapted to this PGPR role (Kennedy et al., 2004), because their ability to grow in conditions of high C:N ratios. However, such diazotrophic PGPRs do not yet provide a technology recognised as reliable enough to justify their application to crops such as rice and wheat on a global scale.
Journal of Plant Nutrition, 2011
Field experiments during two successive rainy seasons were conducted in southern Vietnam to evalu... more Field experiments during two successive rainy seasons were conducted in southern Vietnam to evaluate the effects of a commercial inoculant biofertilizer (‘BioGro’) and fused magnesium phosphate (FMP) fertilizer on yield and nitrogen (N) and phosphorus (P) nutrition of rice. Inoculation with BioGro containing a pseudomonad, two bacilli and a soil yeast significantly increased grain yield in the second season and straw yield in both seasons by 3–5%. The FMP fertilizer significantly increased grain yield from 1.72–2.33 t ha−1 to 2.99–3.58 t ha−1 along with total N and P accumulation at all rates in both cropping seasons. In the first season the difference in grain yield between BioGro treated and untreated plots was marginal but in the second season BioGro out-yielded the control at all the rates of added P. Overall, BioGro application did not compensate for low P fertilizer application to the same extent previously demonstrated for low N fertilizer applications.
PLOS Neglected Tropical Diseases, 2011
Background: An estimated 2.4 billion people live in areas at risk of dengue transmission, therefo... more Background: An estimated 2.4 billion people live in areas at risk of dengue transmission, therefore the factors determining the establishment of endemic dengue in areas where transmission suitability is marginal is of considerable importance. Hanoi, Vietnam is such an area, and following a large dengue outbreak in 2009, we set out to determine if dengue is emerging in Hanoi.
To evaluate risk factors for human infection with influenza A subtype H5N1, we performed a matche... more To evaluate risk factors for human infection with influenza A subtype H5N1, we performed a matched casecontrol study in Vietnam. We enrolled 28 case-patients who had laboratory-confirmed H5N1 infection during 2004 and 106 age-, sex-, and location-matched control-respondents. Data were analyzed by matched-pair analysis and multivariate conditional logistic regression. Factors that were independently associated with H5N1 infection were preparing sick or dead poultry for consumption <7 days before illness onset (matched odds ratio [OR] 8.99, 95% confidence interval [CI] 0.98-81.99, p = 0.05), having sick or dead poultry in the household <7 days before illness onset (matched OR 4.94, 95% CI 1.21-20.20, p = 0.03), and lack of an indoor water source (matched OR 6.46, 95% CI 1.20-34.81, p = 0.03). Factors not significantly associated with infection were raising healthy poultry, preparing healthy poultry for consumption, and exposure to persons with an acute respiratory illness.
PLOS One, 2011
Background: The spread of infectious diseases from person to person is determined by the frequenc... more Background: The spread of infectious diseases from person to person is determined by the frequency and nature of contacts between infected and susceptible members of the population. Although there is a long history of using mathematical models to understand these transmission dynamics, there are still remarkably little empirical data on contact behaviors with which to parameterize these models. Even starker is the almost complete absence of data from developing countries. We sought to address this knowledge gap by conducting a household based social contact diary in rural Vietnam.
Clinical ophthalmology (Auckland, N.Z.), 2014