波音公司的烦恼

今年2月28日,伦敦希斯罗机场上马达轰鸣,一架泛美航空公司的波音747客机呼啸着冲入云天。从它昂首展翅的雄姿中你根本看不出这是一架1969年2月投入使用已经到了退役年龄的老飞机了。它不仅足足飞行了66000小时,大大超过原设计要求,而且经过去年花费2100万美元的大修后(一架波音747客机的造价是为1.5亿美元)又焕然一新。

Mechanism of debismuthizing with calcium and magnesium

In order to further understand the debismuthizing mechanism with calcium and magnesium, the influence of adding amount of calcium on the bismuth removal from lead was examined. A part of the debismuthizing dross samples were studied by electron probe microanalysis （EPMA）. The results show that the calculated bismuthide governing debismuthizing process is Ca3Mg7Bi8, which may be a mixture of Ca3Bi2, CaBi, CaBi3 and Mg3Bi2. And the bismuthide formed during the debismuthizing process exists in two states： one is free bismuthide in the matrix of dross, and the other is symbiotic with Pb-Ca phase.

Method of Jamming C/A Code GPS Receiver

The schemes and effects of electronically jamming GPS’s C/A code receivers are studied by using CW as the narrow band jamming signal and BPSK signal modulated by Gold code which is incoherent to that adopted by GPS as the wide band one. By simulating with Monte Carlo method and programming in Matlab language, the various jamming results in terms of bit error rate under several jamming scenarios are obtained. Through analyzing the simulation results and quantitative dependences of jamming effects on the distance from jammer to GPS receiver and the jammer’s height over ground, it is concluded that jamming with wide band jammer is much more effective than that with narrow band one.

Role of bacteria in the etiopathogenesis of inflammatory bowel disease

Increased numbers of mucosa-associated Escherichia coli are observed in both of the major inflammatory bowel diseases,Crohn's disease(CD)and ulcerative colitis(UC).A potential pathophysiological link between the presence of pathogenic invasive bacteria and genetic host susceptibility of patients with ileal CD is suspected.In CD patients,with increased ileal expression of the CEACAM6 molecule acting as a receptor recognized by type 1 pilus bacterial adhesin,and with the identification of mutations in the NOD2-encoding gene,the presence of pathogenic invasive bacteria could be the link between abnormal ileal bacterial colonization and innate immune responses to invasive bacteria.In a susceptible host,the sequential etiological steps of the disease induced by adherent-invasive E.coli(AIEC)are:(1)abnormal colonization via binding to the CEACAM6 receptor,which is overexpressed in the ileal mucosa of CD patients;(2)ability to adhere to and to invade intestinal epithelial cells,which allows bacteria to cross the mucosal barrier;(3)survival and replication within infected macrophages in the lamina propria;and(4)induction of tumor necrosis factor-α secretion and granuloma formation.

Novel genetic markers in inflammatory bowel disease

Genetic factors play a significant role in determining inflammatory bowel disease(IBD)susceptibility.Epidemiologic data support genetic contribution to the pathogenesis of IBD,which include familial aggregation,twin studies,racial and ethnic differences in disease prevalence.Linkage studies have identified several susceptibility genes contained in different genomic regions named IBD1 to IBD9.Nucleotide oligomerization domain(NOD2)and human leukocyte antigen(HLA)genes are the most extensively studied genetic regions(IBD1 and IBD3 respectively)in IBD.Mutations of the NOD2 gene are associated with Crohn's disease(CD)and several HLA genes are associated with ulcerative colitis(UC)and CD.Toll like receptors(TLRs)have an important role in the innate immune response against infections by mediating recognition of pathogen-associated microbial patterns.Studying single-nucleotide polymorphisms(SNPs)in molecules involved in bacterial recognition seems to be essential to define genetic backgrounds at risk of IBD.Recently,numerous new genes have been identified to be involved in the genetic susceptibility to IBD:NOD1/Caspase-activation recruitment domains 4(CARD4),Chemokine ligand 20(CCL20),IL-11,and IL-18 among others.The characterization of these novel genes potentially will lead to the identification of therapeutic agents and clinical assessment of phenotype and prognosis in patients with IBD.

A Pd-metalated porous organic polymer as a highly efficient heterogeneous catalyst for C–C couplings

An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.

Electrochemical oxidation of rhodamine B by PbO_2/Sb-SnO_2/TiO_2 nanotube arrays electrode

A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD)results showed that the PbO2 coating was composed of anα-PbO2 inner layer and aβ-PbO2 outer layer.Accelerated life measurement indicated that the composite electrode had a lifetime of 815 h.Rhodamine B(RhB)was employed as a model pollutant to analyze the electrocatalytic activity of the electrode.The effects of initial RhB concentration,current density,initial pH,temperature,and chloride ion concentration on the electrochemical oxidation were investigated in detail.Inductively coupled plasma atomic emission spectroscopy(ICP-AES)results suggested that the concentration of leached Pb^2+in the electrolyte during the electrocatalytic oxidation process can be neglected.Finally,the degradation mechanism during the electrocatalytic oxidation process was proposed based on the results of solid-phase micro-extraction-gas chromatography-mass spectrometry(SPME-GC-MS).The high electrocatalytic performance of the composite electrode makes it a promising anode for the treatment of organic pollutants in aqueous solution.

Mean Residence Time of CO2 Molecules in Flexible ZIF-8 Cages Explored by Molecular Dynamics Simulations

The adsorption sites and diffusion mechanism of CO2 molecules in the flexible Zn（MeIM）2 （MeIM=2-methylimidazole） （ZIF-8） have been investigated by grand canonical Monte Carlo and molecular dynamics simulations. A reasonable time correlation function is for the first time constructed to explore the mean residence time of CO2 molecules in the ZIF-8 cages, suggesting that C02 molecules can remain in the same cage for up to several tens of picoseconds. Furthermore, we find that the mean residence time almost linearly increases with the increasing pressure （or loading） at 273 and 298 K.

Behavioral response of tilapia (Oreochromis niloticus) to acute ammonia stress monitored by computer vision

The behavioral responses of a tilapia (Oreochromis niloticus) school to low (0.13 mg/L), moderate (0.79 mg/L) and high (2.65 mg/L) levels of unionized ammonia (UIA) concentration were monitored using a computer vision system. The swimming activity and geometrical parameters such as location of the gravity center and distribution of the fish school were calculated continuously. These behavioral parameters of tilapia school responded sensitively to moderate and high UIA concen-tration. Under high UIA concentration the fish activity showed a significant increase (P<0.05), exhibiting an avoidance reaction to high ammonia condition, and then decreased gradually. Under moderate and high UIA concentration the school’s vertical location had significantly large fluctuation (P<0.05) with the school moving up to the water surface then down to the bottom of the aquarium alternately and tending to crowd together. After several hours’ exposure to high UIA level, the school finally stayed at the aquarium bottom. These observations indicate that alterations in fish behavior under acute stress can provide important in-formation useful in predicting the stress.

One-step random-walk process of nanoparticles in cement-based materials

Efficient modelling approaches capable of predicting the behavior and effects of nanoparticles in cement-based materials are required for conducting relevant experiments.From the microstructural characterization of a cement-nanoparticle system,this paper investigates the potential of cell-based weighted random-walk method to establish statistically significant relationships between chemical bonding and diffusion processes of nanoparticles within cement matrix.LaSr_(0.5)C_(0.5)O_(3)(LSCO)nanoparticles were employed to develop a discrete event system that accounts for the behavior of individual cells where nanoparticles and cement components were expected to interact.The stochastic model is based on annihilation(loss)and creation(gain)of a bond in the cell.The model considers both chemical reactions and transport mechanism of nanoparticles from cementitious cells,along with cement hydration process.This approach may be useful for simulating nanoparticle transport in complex 2D cement-based materials systems.

Random vibration analysis of switching apparatus based on Monte Carlo method

The performance in vibration environment of switching apparatus containing mechanical contact is an important element when judging the apparatus’s reliability. A piecewise linear two-degrees-of-freedom mathematical model considering contact loss was built in this work, and the vibration performance of the model under random external Gaussian white noise excitation was investigated by using Monte Carlo simulation in Matlab/Simulink. Simulation showed that the spectral content and statistical characters of the contact force coincided strongly with reality. The random vibration character of the contact system was solved using time (numerical) domain simulation in this paper. Conclusions reached here are of great importance for reliability design of switching apparatus.

Genetic factors associated with the development of inflammatory bowel disease

Crohn's disease(CD)and ulcerative colitis(UC)are complex polygenic disorders,characterized by several genes together with environmental factors contributing to the development of inflammatory bowel disease(IBD).Recent advances in research on genetic susceptibility have allowed the identification of diverse genes at different levels:(1)Innate immunity;(2)Antigen presentation molecules;(3)Epithelial integrity;(4)Drug transporter;(5)Cell adhesion.The application of genetic testing into clinical practice is close and all genetic markers may have several clinical implications:prediction of disease phenotype,molecular classification,prevention of complications,and prognosis.

Pharmacological Mechanisms of Diazepam in Fish： Effect on Growth

The present work aimed to demonstrate that the dietary content of the drug diazepam, a common benzodiazepine, regulates many aspect of feed efficiency of the Nile tilapia Oreochromis niloticus a favorite in fish production, and also to test introducing a simple new model in the investigation of the biological mechanisms of drug addiction. Diazepam was added to the basic diet at different levels （1.5, 3.0, 5.0, 7.0, 8.0, 9.0, 10.0, 12.0, 14.0 and 16.0 mg/100 g diet）. The experiments lasted for twelve weeks. The results obtained suggested that most of the diazepam doses were able to stimulate the growth parameters of O. niloticus, especially at 12.0 mg/100 gdiet. At some selected doses, diazepam reduces AChE specific activities in the tilapia brain and the inhibition was higher at the 12.0 mg dose. The clearance of diazepam in fish muscles and skin with lapse of time indicated that the fish treatment poses no health risk to the consumer. The recommended dose is the 12 mg DZP/100 mg diet. Finally, tilapia can be used as a new powerful model for the study of fish growth, which could provide insights into the mechanisms of drug addiction.

The Impact of Unrealized Foreign Exchange Differences for Accounting and Taxation

The present study is intended to be an analysis of the main Romanian legal provision in what concerns the impact of foreign exchange differences and potential consequences at the level of financial statements for companies. In Romanian legislation, the issue of the foreign exchange differences is treated at a general level： these are recognized as a profit and loss item and as a consequence, they are included in the taxable base when booked in the accounting. Our legislation does not provide for specific treatments depending on the ＇realization momenf＇ of these differences or depending on the conditions for recognizing a gain/loss from foreign exchange differences. For the unrealized exchange differences arising from the application of accounting rules on monthly assessment of foreign currency monetary items, there is not a specific event or transaction to determine income or expenditure. This monthly review depending on the National Bank of Romania [BNR] foreign exchange rate valid on the last day of the month aims to bring closer to reality the financial position of an entity. The exchange rate is a monetary policy item set by the central bank and may be influenced by various factors such as： monetary policy of the BNR; inflation target objectives and rate of exchange stabilization or reduction efforts, as is the case of BNR in the last years to fulfill EU criteria for adoption of the EURO; periodical influences of speculative capitals on the exchange rate level; economic status and especially exports and imports. However, a taxpayer should not be charged unless there is evidence of the ＂economic enrichment＂ thereof. However, this enrichment, seen as a rising economic value of the company, depends on the perspective from which is seen： the owner of the company or the tax authorities. The exchange differences impact also the value of the owners＇ equity for which a minimum level is requested under the commercial company law. In case of negative values, this triggers various risks at the level of the continuity principle or even endangers the existence of the company.

Growth Mechanism of Microcrystalline Silicon Films by Scaling Theory and Monte Carlo Simulation

Hydrogenated microcrystalline silicon （~c-Si：H） films with a high deposition rate of 1.2nm/s were prepared by hot-wire chemical vapor deposition （HWCVD）. The growth-front roughening processes of the μc-Si..H films were investi- gated by atomic force microscopy. According to the scaling theory, the growth exponent β≈0.67, the roughness exponent α≈0.80,and the dynamic exponent 1/z = 0.40 are obtained. These scaling exponents cannot be explained well by the known growth models. An attempt at Monte Carlo simulation has been made to describe the growth process of μc-Si： H film using a particle reemission model where the incident flux distribution,the type and concentration of growth radical, and sticking,reemission,shadowing mechanisms all contributed to the growing morphology.

Energy conservation research of dehumidification system for main cable anticorrosion of suspension bridge

The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge is calculated, and the results show that energy conservation rate can reach 44 %.

Study on High Order Perturbation-based Nonlinear Stochastic Finite Element Method for Dynamic Problems

Several algorithms were proposed relating to the development of a framework of the perturbation-based stochastic finite element method (PSFEM) for large variation nonlinear dynamic problems. For this purpose, algorithms and a framework related to SFEM based on the stochastic virtual work principle were studied. To prove the validity and practicality of the algorithms and framework, numerical examples for nonlinear dynamic problems with large variations were calculated and compared with the Monte-Carlo Simulation method. This comparison shows that the proposed approaches are accurate and effective for the nonlinear dynamic analysis of structures with random parameters.

A randomized,double-blind,placebo-controlled trial assessing the efficacy and safety of tegaserod in patients from China with chronic constipation

AIM： To evaluate the efficacy and safety of tegaserod, 6 mg twice daily （b.i.d.）, in men and women with chronic constipation （CC） from China. METHODS： This was a multicenter, double-blind, placebo-controlled study. Following a 2-wk treatmentfree baseline period, patients were randomized to receive either tegaserod （6 mg b.i.d.） or placebo （b.i.d.） for 4 wk. An analysis of covariance with repeated measures was used to determine the overall effect of treatment for the primary efficacy variable; the change from baseline in the number of complete spontaneous bowel movements （CSBMs） during the 4-wk treatment period. Secondary efficacy endpoints included other measures of response in terms of CSBMs, and patients＇ daily and weekly assessment of bowel habits. Safety was also assessed, based on the incidence and severity of adverse events （AEs）. RESULTS： A total of 607 patients were randomized to receive either tegaserod （n = 304） or placebo （n = 303）. Tegaserod treatment resulted in a rapid and significant increase from baseline in the adjusted mean number of CSBMs per week over wk 1-4 compared with placebo （1.39 vs 0.91, P = 0.0002）. A statistically significant difference in favor of tegaserod was also observed for a mean increase ≥ 1 CSBM/wk over wk 1-4 （47.7% vs 35.0%, tegaserod vs placebo, respectively, P = 0.0018） and for the absolute number of≥ 3 CSBMs/wk over wk 1-4 （25.0% vs 14.5%, tegaserod vs placebo, respectively, P = 0.0021）. Improvements in other symptoms of CC were also seen in the tegaserod group, including improved stool form and reduced straining. In addition, more patients in the tegaserod group reported satisfactory relief from their constipation symptoms. The frequency and severity of AEs was comparable between tegaserod and placebo groups, with the exception of a greater incidence of diarrhea in patients receiving tegaserod （3.6%） compared with placebo （1.7%）. CONCLUSION： Tecjaserod treatment improved multiple symptoms of CC and was associated with a favorable safety profile.

Control of the Colorado Potato Beetle, Leptinotarsa decemlineata （Say）, Using Predator Insects Released by a Mechanical Prototype

The CPB （Colorado potato beetle） is unquestionably the major insect pest of potato crops in North America, Europe, and Asia. The use of chemical insecticides to control this insect pest started in the 1860s. To date, no registered chemical has been capable of effectively managing this agricultural pest. Moreover, the CPB has developed over the years a resistance to most of the registered chemical insecticides. The biological control through manual release of natural enemies of the CPB has been successful at small scale. However, hand release of these predators at large scale is not realistic. The objective of this study was to investigate the effectiveness of controlling the CPB through mechanical release of predator insects under real conditions in a potato field. Obtained results indicate that the mechanical release of predator insects resulted in a better control of the CPB populations and egg masses than the manual release. The success of this mechanical release of predator insects in potato fields will be highly valuable for the biological control of insect pests in many other row crops such as strawberry, lettuce, etc..

Kazakh Nationalism in Eurasian Context

This abstract has concerned primarily with the new look to the stages of post-Soviet Kazakh nationalism development embedded in context of Eurasian concept. Could we prove true widely held predictions about future strengthening of nationalists＇ position in post-crisis country？ As we state, opposite to above mentioned ideas, the more Kazakhstan would be involved in to Russian politics orbit which means further movement to Eurasian ＂path＂ the more undermined should be Kazakh nationalists conventional certainties. Moreover, one of the world crisis consequences could be displayed in leadership authoritarian tendencies strengthening. The latter undoubtedly ought to erode Kazakh nationalists＇ position.