Inference of Allelopathy about Spartina Alterniflora to Scirpus Mariqueter by Effects of Activated Carbon on Soil

AbstractSpartina alterniflora Loisel is an invasive species in Jiuduansha Islands and threatens the survival of native species Scirpus mariqueter. In this study, activated carbon (AC) was applied to study the allelochemicals remained in the soil. Seed germination and seedling growth bioassays were used to test the allelopathic effect, and GC-MS was used to identify the allelochemicals. Our results showed: due to the invasion of S. alterniflora, germination of S. mariqueter seeds and the growth of seedlings were significantly inhibited. When AC was added into S. mariqueter soil, the germination had not been affected while the seedling growth was promoted significantly. When AC was added into the soil of S. alterniflora, both the germination and the seedling growth had an obvious improvement. All indicated that S. alterniflora soil contained allelochemicals which would be absorbed by AC. The identified allelochemicals were hexadecanoic acid, octadecanoic acid, dibutyl phthalate, (adipic acid, isohexyl methyl ester) and (adipic acid, di (oct-4-yl ester))

Rare B Decays with a HyperCP Particle of Spin One

In light of recent experimental information from the CLEO, BaBar, KTeV, and Belle collaborations, we investigate some consequences of the possibility that a light spin-one particle is responsible for the three Sigma^+ -> p mu^+ mu^- events observed by the HyperCP experiment. In particular, allowing the new particle to have both vector and axial-vector couplings to ordinary fermions, we systematically study its contributions to various processes involving b-flavored mesons, including B-Bbar mixing as well as leptonic, inclusive, and exclusive B decays. Using the latest experimental data, we extract bounds on its couplings and subsequently estimate upper limits for the branching ratios of a number of B decays with the new particle. This can serve to guide experimental searches for the particle in order to help confirm or refute its existence.Comment: 17 pages, 3 figures; discussion on spin-0 case modified, few errors corrected, main conclusions unchange

Byssinosis in Guangzhou, China

Objectives - To study the prevalence of byssinosis and other respiratory abnormalities in workers exposed to cotton dust in Guangzhou in two factories that processed purely cotton. Methods - All the 1320 workers exposed were included. The controls were 1306 workers with no history of occupational dust exposure. Total dust and inhalable dust were measured by Chinese total dust sampler and American vertical elutriator respectively. A World Health Organisation questionnaire was used. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV 1) were measured by a Vitalograph spirometer. Results - The median inhalable dust concentrations ranged from 0.41 to 1.51 mg/m 3 and median total dust concentrations from 3.04 to 12.32 mg/m. The prevalence of respiratory abnormalities in the cotton workers were (a) typical Monday symptoms 9.0%; (b) FEV 1 fall by ≥ 5% after a shift 16.8%; (c) FEV 1 fall by ≥ 10% after a shift 4.2%; (d) FEV'q < 80% predicted 6.1%; (e) FEV 1/FVC < 75% 4.0%; (f) cough or phlegm 18.2%; (g) chronic bronchitis 10-9%; and (h) byssinosis, defined by (a) plus (b) 1.7%. With the exception of (d), most of the prevalences increased with increasing age, duration of exposure, and cumulative inhalable dust exposure. No increasing trends of respiratory abnormalities were found for current total dust, inhalable dust, and cumulative total dust concentrations. Compared with controls, after adjustment for sex and smoking, with the exception of (d), all the pooled relative risks of respiratory abnormalities were raised for cotton exposure. Conclusions - It is concluded that cumulative inhalable cotton is likely to be the cause of byssinotic symptoms, acute lung function decrements, cough, or phlegm, and chronic bronchitis.published_or_final_versio

Mechanical Properties of Silicon Nanowires

Nanowires have been taken much attention as a nanoscale building block, which can perform the excellent mechanical function as an electromechanical device. Here, we have performed atomic force microscope (AFM)-based nanoindentation experiments of silicon nanowires in order to investigate the mechanical properties of silicon nanowires. It is shown that stiffness of nanowires is well described by Hertz theory and that elastic modulus of silicon nanowires with various diameters from ~100 to ~600 nm is close to that of bulk silicon. This implies that the elastic modulus of silicon nanowires is independent of their diameters if the diameter is larger than 100 nm. This supports that finite size effect (due to surface effect) does not play a role on elastic behavior of silicon nanowires with diameter of >100 nm