The Empirical Analysis of Cigarette Tax Avoidance and Illicit Trade in Vietnam, 1998-2010

Illicit trade carries the potential to magnify existing tobacco-related health care costs through increased availability of untaxed and inexpensive cigarettes. What is known with respect to the magnitude of illicit trade for Vietnam is produced primarily by the industry, and methodologies are typically opaque. Independent assessment of the illicit cigarette trade in Vietnam is vital to tobacco control policy. This paper measures the magnitude of illicit cigarette trade for Vietnam between 1998 and 2010 using two methods, discrepancies between legitimate domestic cigarette sales and domestic tobacco consumption estimated from surveys, and trade discrepancies as recorded by Vietnam and trade partners. The results indicate that Vietnam likely experienced net smuggling in during the period studied. With the inclusion of adjustments for survey respondent under-reporting, inward illicit trade likely occurred in three of the four years for which surveys were available. Discrepancies in trade records indicate that the value of smuggled cigarettes into Vietnam ranges from $100 million to $300 million between 2000 and 2010 and that these cigarettes primarily originate in Singapore, Hong Kong, Macao, Malaysia, and Australia. Notable differences in trends over time exist between the two methods, but by comparison, the industry estimates consistently place the magnitude of illicit trade at the upper bounds of what this study shows. The unavailability of annual, survey-based estimates of consumption may obscure the true, annual trend over time. Second, as surveys changed over time, estimates relying on them may be inconsistent with one another. Finally, these two methods measure different components of illicit trade, specifically consumption of illicit cigarettes regardless of origin and smuggling of cigarettes into a particular market. However, absent a gold standard, comparisons of different approaches to illicit trade measurement serve efforts to refine and improve measurement approaches and estimates.     

Diet of the Indochinese silvered langur (Trachypithecus germaini) in Kien Luong Karst area,Kien Giang Province

The Indochinese silvered langur (Trachypithecus germaini) is distributed to the west of Mekong River in Cambodia, Lao PDR, Thailand and Vietnam. During a two‐year study, from May 2014 to May 2016, we collected 320.44 hr of behavior, with 17,040 feeding bouts recorded (142 hr) for T. germaini on Chua Hang Karst Mountain, Kien Luong District, Kien Giang Province, Vietnam. Feeding accounted for 45% of the Indochinese silvered langurs’ activity budget. The plant diet of the Indochinese silvered langurs was principally composed of young leaves (58%), followed by mature leaves (9.5%), fruits (22.7%), flowers (4.7%), buds (3.3%), petioles (1.2%), and other (0.5%). A total of 58 plant species were fed on by the silvered langurs, and leaves of eight species (Phyllathus reticulatus, Ficus rumphii, Ficus tinctoria, Ficus microcarpa, Cayratia trifolia, Streblus ilicifolia, Combretum latifolium, and Streblus asper) were fed on throughout the year. P. reticulatus was most frequently eaten (13.9% feeding time, n = 1,733). Food selection differed significantly between months and seasons. The Indochinese silvered langurs ate 27 plant species in the wet season compared with 23 plant species in the dry season. Leaf chemical composition of two food categories, 16 eaten species (with 10 most frequently consumed species and six least consumed species), and four noneaten species, were analyzed. Feeding samples from eaten species in the Indochinese silvered langurs's diet contained lower amounts of condensed tannin, lignin, protein, ash, and lipids, but a higher amount of total sugar compared with samples from noneaten species. Furthermore, the most frequently consumed species contained lower amounts of lignin compared with the less frequently consumed species. Using a generalized linear model with five variables, including neutral detergent fiber (NDF), total sugar, lignin, lipid, and calcium (Ca) indicated that NDF positively correlated and lignin content negatively correlated with feeding records in the diet of these langur.     

Limited chloroplast gene transfer via recombination overcomes plastomegenome incompatibility between Nicotiana tabacum and Solanum tuberosum

Green cybrids with a new nucleus-chloroplast combination cannot be selected after protoplast fusion in the intersubfamilial Nicotiana-Solanum combination. As an approach to overcome the supposed plastomegenome incompatibility, a partial plastome transfer by genetic recombination has been considered. After fusions of protoplasts of a light-sensitive Nicotiana tabacum (tobacco) plastome mutant and lethally irradiated protoplasts of wild-type Solanum tuberosum (potato), a single green colony was recovered among 2.5×10⁴ colonies. The regenerated plants had tobacco-like (although abnormal) morphology, but were normally green, and sensitive to tentoxin, demonstrating chloroplast markers of the potato parent. Restriction enzyme analysis of the chloroplast DNA (cpDNA) revealed recombinant, nonparental patterns. A comparison with physical maps of the parental cpDNA demonstrated the presence of a considerable part of the potato plastome flanked by tobacco-specific regions. This potacco plastome proved to be stable in backcross and backfusion experiments, and normally functional in the presence solely of N. tabacum nucleus.     

Medicago truncatula,a model plant for studying the molecular genetics of theRhizobium-legume symbiosis

Medicago truncatula has all the characteristics required for a concerted analysis of nitrogen-fixing symbiosis withRhizobium using the tools of molecular biology, cellular biology and genetics.M. truncatula is a diploid and autogamous plant has a relatively small genome, and preliminary molecular analysis suggests that allelic heterozygosity is minimal compared with the cross-fertilising tetraploid alfalfa (Medicago sativa). TheM. truncatula cultivar Jemalong is nodulated by theRhizobium meliloti strain 2011, which has already served to define many of the bacterial genes involved in symbiosis with alfalfa. A genotype of Jemalong has been identified which can be regenerated after transformation byAgrobacterium, thus allowing the analysis ofin-vitro-modified genes in an homologous transgenic system. Finally, by virtue of the diploid, self-fertilising and genetically homogeneous character ofM. truncatula, it should be relatively straightforward to screen for recessive mutations in symbiotic genes, to carry out genetic analysis, and to construct an RFLP map for this plant.     

Human esterase D gene: complete cDNA sequence,genomic structure,and application in the genetic diagnosis of human retinoblastoma

Summary The gene encoding human esterase D (EsD), a member of the nonspecific esterase family, is a useful genetic marker for retinoblastoma (RB) and Wilson's disease. Previously we identified a cDNA clone from this gene and determined its chromosomal location. In this report, we present the complete cDNA sequence of the human EsD gene. A long open reading frame encoded a predicted protein of 282 amino acids with molecular weight of 30 kD. A computer-assisted search of a protein sequence data base revealed homology with two other esterases, acetylcholinesterase of Torpedo and esterase-6 of Drosophila. Homologous region were centered around presumptive active sites, suggesting that the catalytic domains of the esterases are conserved during evolution. Three genomic clones of this gene were also isolated and characterized by restriction mapping. At least ten exons were distributed over a 35-kb (kilobase pair) region; each exon contained an average of 100 basepairs (bp). A polymorphic site for Apa I, located within an intron of the esterase D gene, can be used to identify chromosome 13 carrying defective RB alleles within retinoblastoma families.     

Measurements of genetic variability for symbiotic dinitrogen fixation in fieldgrwon fababean (Vicia faba L.) using a low level15N-tracer technique

Before starting a breeding program aimed at improving the nitrogen nutrition ofVicia faba, the authors tried an alternative technique to the acetylene reduction assay, to measure some genetic variability in the plant material. The quantity of dinitrogen fixed by several cultivars ofVicia faba was estimated using a low enrichment¹⁵N tracer method and high precision¹⁵N mass spectrometry. The fababeans were cultivated for two years in two different soils. The percentage of fixed dinitrogen in the seed varied between genotypes from 40 to 83% of the total nitrogen and was positively correlated with the total seed nitrogen (r=0.64 to 0.86). A highly significant positive correlation was also found between the total seed nitrogen and the quantity of fixed dinitrogen in the seed (r=0.95 to 0.99). The technique used to measure dinitrogen fixation proved to be useful and reliable enough to discriminate between various genotypes, grown over a period of two years in two different soils. However, several non-fixing control plants showed significant differences in their¹⁵N enrichment and the problem of choosing a good reference plant was raised and discussed.     

A stochastic model of mutant growth due to mutation in tumors,based on stem cell considerations

A stochastic model of the evolution of mutant subpopulations from stem cells in a human tumor system is derived. From the model, the growth of mutants (both stem cell mutants and overall mutants) due to mutation of tumor stem cells during growth is explored in detail. This allows one to relate the mutant stem cell and overall tumor mutant cell population sizes. The relation of these average sizes is derived for large tumor size and confirms the result of the model due to MacKillop et al. [4], which is based on three tumor cell subpopulations: stem, transitional, and end cells. Furthermore, the results of the stem cell statistics obtained are the same as those obtained from the filtered Poisson process approach [2].     

Neurophysiology of geniculate ganglion (facial nerve) taste systems: species comparisons

On the basis of various measures taken from geniculate gangliontaste neurons in four species, it was concluded that withineach species the neurons could be subdivided into distinct functionalgroups. In this report, the neural groups of different specieswere directly compared. Units from all four species were studiedwith a common test series of solutions in addition to otherstimuli. Since these stimuli were presented at the same concentrationsto all species, direct quantitative comparisons across specieswere possible for a wide range of chemical compounds. In addition,the neural groups were compared with respect to spontaneousand evoked activity measures, latency to electrical stimulation,and receptive field characteristics. These neurophysiologicaldata suggest a basic model of four distinct subgroups: acidunits, salt units, amino acid units, and X units.     

ATP sulfurylase from Penicillium chrysogenum: measurements of the true specific activity of an enzyme subject to potent product inhibition and a reassessment of the kinetic mechanism

Homogeneous ATP sulfurylase from Penicillium chrysogenum has been reported to have an extremely low activity toward its physiological inorganic substrate, sulfate. This low activity is an artifact resulting from potent product inhibition by 5'-adenylylsulfate (APS) (Ki less than 0.25 microM). Assays based on 35S incorporation from 35SO4(2-) into charcoal-adsorbable [35S]APS are nonlinear with time, even in the presence of a large excess of inorganic pyrophosphatase. However, in the presence of excess APS kinase (along with excess pyrophosphatase), the ATP sulfurylase reaction is linear with time and the enzyme has a specific activity (Vmax) of 6 to 7 units mg protein-1 corresponding to an active site turnover number of at least 400 min-1. Monovalent oxyanions such as NO3-, ClO3-, ClO4-, and FSO3- are competitive with sulfate (or molybdate) and essentially uncompetitive with respect to MgATP. However, thiosulfate (SSO3(2-)), a true sulfate analog and dead-end inhibitor of the enzyme (competitive with sulfate or molybdate), exhibited clear noncompetitive inhibition against MgATP. Furthermore, APS was competitive with both MgATP and molybdate in the molybdolysis assay. These results suggest (a) that the mechanism of the normal forward reaction may be random rather than ordered and (b) that the monovalent oxyanions have a much greater affinity for the E X MgATP complex than for free E. In this respect, FSO3-, ClO4-, etc., are not true sulfate analogs although they might mimic an enzyme-bound species formed when MgATP is at the active site. The nonlinear ATP sulfurylase reaction progress curves (with APS accumulating in the presence of excess pyrophosphatase or PPi accumulating in the presence of excess APS kinase) were analyzed by means of "average velocity" plots based on an integrated rate equation. This new approach is useful for enzymes subject to potent product inhibition over a reaction time course in which the substrate concentrations do not change significantly. The analysis showed that ATP sulfurylase has an intrinsic specific activity of 6 to 7 units mg protein-1. Thus, the apparent stimulation of sulfurylase activity by APS kinase results from the continual removal of inhibitory APS rather than from an association of the two sulfate-activating enzymes to form a "3'-phospho-5'-adenylylsulfate synthetase" complex in which the sulfurylase has an increased catalytic activity. The progress curve analyses suggest that APS is competitive with both MgATP and sulfate, while MgPPi is a mixed-type inhibitor with respect to both substrates. The cumulative data point to a random sequence for the forward reaction with APS release being partially rate limiting.