Some Aspects of the Ecology of Elaeidobius Kamerunicus Faust, The Pollinating Weevil of Oil Palm, With Emphasis on Developing Sampling Techniques

Some aspects of the ecology of the pollinating weevil of oil palm, Elaeidobius kamerunicus Faust - an exotic insect to Malaysia imported from Cameroon, West Africa, three years ago - were studied in 1983 and 1984. In particular, sampling techniques for estimating the weevil population were developed and the effect of rat predation on the immature weevils was studied. In the course of these studies, certain aspects of the weevil's behaviour and activity were investigated. Field studies concerning the ecology of the weevil requires a satisfactory method for estimating the weevil population. Three sampling methods were compared: petridish traps set on receptive female inflorescences, sticky traps incorporating anthesising male flowers as bait, and sampling the weevil-covered spikelets of the anthesising male inflorescence. The last method was found to be superior it was more reliable and the data could be converted to an absolute estimate. To be reliable, the method must consider the time of sampling, stage of anthesis of the male inflorescence, and position of spikelet on the male inflorescence. Taking samples after 5 pm, separating the anthesising male inflorescences into three stages, and stratified sampling from six sections of the male inflorescence were found to be optimal for a reliable estimation

Optical transitions between Landau levels: AA-stacked bilayer graphene

The low-frequency optical excitations of AA-stacked bilayer graphene are investigated by the tight-binding model. Two groups of asymmetric LLs lead to two kinds of absorption peaks resulting from only intragroup excitations. Each absorption peak obeys a single selection rule similar to that of monolayer graphene. The excitation channel of each peak is changed as the field strength approaches a critical strength. This alteration of the excitation channel is strongly related to the setting of the Fermi level. The peculiar optical properties can be attributed to the characteristics of the LL wave functions of the two LL groups. A detailed comparison of optical properties between AA-stacked and AB-stacked bilayer graphenes is also offered. The compared results demonstrate that the optical properties are strongly dominated by the stacking symmetry. Furthermore, the presented results may be used to discriminate AABG from MG, which can be hardly done by STM

Optimal production-shipment decisions for the finite production rate model with scrap

This paper is concerned with the decision-making on the optimal production batch size and optimal number of shipments for a finite production rate model with random scrap rate. The classic finite production rate (FPR) model assumes a continuous inventory issuing policy for satisfying product demand and perfect quality for all items produced. However, in a real life vendor-buyer integrated production-inventory system, a multiple shipment policy is practically used in lieu of the continuous issuing policy, and it is inevitable to generate defective items during a production run. All nonconforming items produced are assumed to be scrap, and the finished (perfect quality) products can only be delivered to customers if the whole lot is quality assured at the end of the production run. The fixed-quantity multiple instalments of the finished batch are delivered to customers at a fixed interval of time. Mathematical modelling is employed and the renewal reward theorem is used to cope with the variable production cycle length. The long-run average cost for the proposed model is derived, and its convexity is proved by the use of the Hessian matrix equations. A closed-form optimal production-shipment policy for such an imperfect FPR model is obtained and a special case is discussed. Finally, a numerical example is provided to demonstrate the model’s practical usage

Sleep duration and patterns in Chinese older adults: A comprehensive meta-analysis

This meta-analysis examined the mean sleep duration and patterns in Chinese older adult population. A literature search was systematically conducted covering major English (PubMed, Embase and PsycINFO) and Chinese (Chinese National Knowledge Infrastructure (CNKI), WanFang and SinoMed) databases. Data in studies with the mean and standard deviation of sleep duration and/or the proportion of short and long sleep durations in Chinese older adults were extracted and pooled using random-effects models. Subgroup analyses were conducted according to gender, region, area, survey time and sample size. A total of 36 studies with 150,616 subjects were included for analyses. The pooled mean sleep duration of 21 studies with available data was 6.82 hours/day (95% CI: 6.59–7.05 hours/day). The estimated proportions of sleep duration \u3c5 hours/day, \u3c6 hours/day, \u3c7 hours/day were 18.8% (95% CI: 1.7%–35.9%), 26.7% (95% CI: 19.7%–33.7%) and 42.3% (95% CI: 34.8%–49.8%), respectively. The pooled proportions for long sleepers were 22.6% (95% CI: 13.9%–31.4%) (\u3e8 hours/day) and 17.6% (95% CI: 12.4%–22.9%) (\u3e9 hours/day). Given the adverse effects of unhealthy sleep patterns, health professionals should pay more attention to sleep patterns in this population in China

3-[(8-But­oxy­quinolin-2-yl)meth­yl]-1-(pyridin-2-ylmeth­yl)-1H-imidazol-3-ium hexa­fluoridophosphate

In the cation of the title compound, C23H25N4O+·PF6 −, the imidazolium ring make dihedral angles of 87.20 (6) and 79.89 (5)° with the pyridine ring and the quinoline system, respectively. In the crystal, C—H⋯F and C—H⋯N hydrogen bonds are observed