Graded English Series (GES)—A Possible Way Out for the Reform of the English Teaching in China

To explore an effective way to change the awkward present situation of the examination-handling education in the English teaching in China, the vocabulary was defined as the only criterion to judge the level of a person’s English learning and the only quantified index to be tested, an exclusive programme was compiled to formulate a graded vocabulary list by use of the world’s authoritative corpora and various word lists, a vocabulary testing and analyzing system for English passages was developed, 3,000 English passages of 60-600 words were chosen, tested and analyzed one by one by means of the newly-developed graded vocabulary list, then, the passages were automatically classified into different grades with the vocabulary coverage rate (VCR) of >95% as the criterion, each was put in order and included into the corresponding grade, and then the passages in the same grade were properly arranged to form “Graded English Series” (“GES”), which satisfied the two conditions of the vocabulary coverage scope and rate, realizing the principle of ‘proceeding in an orderly way and step by step’ in the real meaning and giving a possibility of achieving the effect of ‘half efforts but double gains’ in teaching, and thus served as a cure for the stubborn and persistent ailment of the examination-handling teaching and an effective way to exercise the quality education in English teaching

Impact of Mountain Pine Beetle-Attacked Lodgepole Pine Logs on Veneer Processing

Pilot plant tests and mill trials were conducted to quantify the impact of using mountain pine beetle(MPB)-attacked lodgepole pine (Pinus contorta Dougl.) wood on green veneer processing, and determine if it makes economic sense to sort and process MPB logs separately from normal logs of white SPF (spruce-lodgepole pine-alpine fir) mix for plywood manufacturing. The results demonstrated that log dry-out, improper log conditioning, and veneer peeling contribute to the breakage of veneer ribbon, and in turn, loss of veneer recovery at the green end when processing MPB wood. Compared with the green SPF veneer controls, green MPB veneer has lower moisture content (MC) with smaller variation. The MPB veneer can be clipped narrower with an equivalent of 1% increase in recovery due to less width shrinkage, and be sorted more accurately requiring only two green sorts: heart and light-sap. The MPB veneer can also be dried faster with a reduction in drying time by about 25% for the heart veneer and 35% for the light-sap veneer. However, due to higher volume of narrower random sheets and increased waste from manual handling and composing, the net recovery of the MPB logs is about 8% lower than that of the control SPF logs. Furthermore, the color of the stained MPB veneer is lightened after drying, but it still causes interference with visual grading. Since MPB wood has unique MC and processing characteristics, it is recommended that it be sorted in the log yard when its proportion reaches about 10% of the total logs procured

THE FEASIBILITY OF APPLYING COMPUTER-AIDED DESIGN IN COMPETITIVE SPORTS EXERCISES

The purpose of this study is to determine the feasibility of applying the principles of Computer-Aided- Design to research into human movement. It could be of considerable importance to future research in biomechanics to combine the technology of Computer- Aided Design (CAD) and computer image processing with the imaginative power, creativity and experience of instructors, athletes and sports science researchers. It is also critical to design fast and efficient competition exercises and to replace the traditional ways of design with advanced science and technology. This paper will introduce the design principle, the characteristics, as well as the structure of the system, the working environment, the technology of application and effect analysis

Impact of Mountain Pine Beetle-Attacked Lodgepole Pine Logs on Plywood Manufacturing

In this work, the possibility of increasing value recovery from mountain pine beetle (MPB)-attacked lodgepole pine (Pinus contorta Dougl.) logs was further investigated, including veneer grading, gluing, panel lay-up, and hot-pressing. This was a follow-up to an earlier study that demonstrated that, by segregating MPB logs, the value recovery could be improved through narrower veneer clipping width, more accurate moisture sorting, and greater drying productivity. Based on pilot plant tests, compared with control veneer of spruce—lodgepole pine—alpine fir (SPF), MPB veneer had various degrees of bluestain, and was significantly denser and stiffer. To minimize manufacturing costs for MPB plywood, glue spread can be kept at the same level as currently used by control SPF plywood. However, the pressing time of 5-ply MPB plywood should be lengthened by about 10% compared with that used by the 5-ply control SPF counterpart. The assembly time should be maintained within 10 to 15 min, keeping veneer temperature as low as possible. Furthermore, the parallel-ply MOE and MOR of 5-ply MPB plywood were approximately 15 and 20% higher than those of 5-ply control SPF plywood, respectively. As a result, MPB veneer was more suitable for making specialty plywood products requiring high stiffness and strength. If manufacturing parameters are properly adjusted in grading, gluing, and hot-pressing, segregating MPB logs from the normal SPF mix also provides an opportunity to manufacture high stiffness plywood with superior dry- and wet-gluebond performance. This could further offset, to a large degree, the reduction in material recovery and the loss in market share for some appearance-based plywood products

Veneer Surface Roughness and Compressibility Pertaining to Plywood/LVL Manufacturing. Part II. Optimum Panel Densification

In Part I of this series, a novel method was proposed to assess surface roughness/quality and compressibility of wood veneer, and the wood compression theory was revised to include the first stage of "progressive contact." Based on this revised theory, the minimum compression required can be established for achieving adequate contact of veneer-to-veneer (or plate), and true veneer yield displacement can be determined. Owing to the variation of veneer compressibility and random veneer placement in the panel assembly, this study aimed to apply the revised theory to establish the optimum panel densification for performance plywood and laminated veneer lumber (LVL) manufacturing. Using 3.2-mm-thick rotary cut trembling aspen (Populus tremuloides) veneer as an example, the correlation between the contact area and panel compression ratio (CR) was first established in terms of veneer surface roughness. Then, the required aspen panel CR and density were identified for achieving a target 80% contact area of veneer-to-veneer (or plate). Meanwhile, through the compression tests of 30- x 30-mm aspen veneer specimens, within-sheet and between-sheet variations in density, thickness, and compressibility were revealed. Furthermore, based on the frequency distribution of the minimum compression required and yield displacement for aspen veneer, the optimum range of aspen panel densification was identified with a CR ranging from 11.3% to 18.0%. Finally, through the manufacturing of aspen panels, such densification range identified was validated for improved panel quality, material recovery, and dimensional stability while achieving superior panel bending and gluebond performance

Veneer Surface Roughness and Compressibility Pertaining to Plywood/LVL Manufacturing. Part I. Experimentation and Implication

Extensive experiments were conducted to examine the transverse compression behavior of trembling aspen (Populus tremuloides) veneer at ambient and controlled temperature and moisture content (MC) environments, and the relationship between contact area, veneer surface roughness, and applied load. Based on the results, a novel method was developed to characterize surface roughness/quality of wood veneer in terms of its compression behavior. This method may have significant implication on both theory and practice. In theory, the general wood transverse compression theory needs to be revised to include four stages instead of the commonly defined three. The first stage, which has long been overlooked but is critically important, could be named "progressive contact." During this stage, the contact area increases nonlinearly with the load applied. It is this stage that reveals the interfacial contact of veneer-to-veneer or veneer-to-plate and the minimum veneer compression required for achieving adequate contact. With the inclusion of the first stage, the yield displacement also needs to be redefined. In practice, the method provides a fast and objective way of evaluating veneer surface roughness/quality for plywood/LVL manufacturing. Furthermore, the minimum compression required and yield displacement of wood veneer derived from its compressive load-displacement curve were found to be independent of temperature and MC, which helps benchmark material recovery in terms of veneer surface roughness/quality when manufacturing into quality plywood/LVL products. The method could also be applied to other wood composite elements such as wood strands

Antimicrobial peptides as novel alternatives to antibiotics

In recent years, due to the unreasonable use of antibiotics, bacterial resistance has increased, posing a huge threat to human health and the healthy development of the swine industry. Therefore, it is an urgent to look for antibiotic alternatives. Antimicrobial peptides are a class of small molecule peptides, which are the body's first line of defense against the invasion of pathogenic microorganisms. They have small molecular weight, good water solubility, and not easy to produce drug resistance. Therefore, antimicrobial peptides are considered as one of the best alternatives to antibiotics. This review focuses on the mechanism of action of antimicrobial peptides, especially improve performance, improve intestinal inflammation and nutrient digestibility, regulate the intestinal microbiota and enhance the immune function of swine. Overall, AMPs have great potential for application  as an alternative to antibiotics in swine industry

The virulence factor regulator and quorum sensing regulate the type I-F CRISPR-Cas mediated horizontal gene transfer in Pseudomonas aeruginosa

Pseudomonas aeruginosa is capable of thriving in diverse environments due to its network of regulatory components for effective response to stress factors. The survival of the bacteria is also dependent on the ability to discriminate between the acquisition of beneficial and non-beneficial genetic materials via horizontal gene transfer (HGT). Thus, bacteria have evolved the CRISPR-Cas adaptive immune system for defense against the deleterious effect of phage infection and HGT. By using the transposon mutagenesis approach, we identified the virulence factor regulator (Vfr) as a key regulator of the type I-F CRISPR-Cas system in P. aeruginosa. We showed that Vfr influences the expression of the CRISPR-Cas system through two signaling pathways in response to changes in calcium levels. Under calcium-rich conditions, Vfr indirectly regulates the CRISPR-Cas system via modulation of the AHL-QS gene expression, which could be vital for defense against phage infection at high cell density. When encountering calcium deficiency, however, Vfr can directly regulate the CRISPR-Cas system via a cAMP-dependent pathway. Furthermore, we provide evidence that mutation of vfr reduces the CRISPR-Cas spacer acquisition and interference of HGT. The results from this study add to the regulatory network of factors controlling the CRISPR-Cas system in response to abiotic factors in the environment. The findings may facilitate the design of effective and reliable phage therapies against P. aeruginosa infections, as targeting Vfr could prevent the development of the CRISPR-Cas mediated phage resistance

Nutrient Availability and Phage Exposure Alter the Quorum-Sensing and CRISPR-Cas-Controlled Population Dynamics of Pseudomonas aeruginosa

Quorum sensing (QS) coordinates bacterial communication and cooperation essential for virulence and dominance in polymicrobial settings. QS also regulates the CRISPR-Cas system for targeted defense against parasitic genomes from phages and horizontal gene transfer. Although the QS and CRISPR-Cas systems are vital for bacterial survival, they undergo frequent selection in response to biotic and abiotic factors. Using the opportunistic Pseudomonas aeruginosa with well-established QS and CRISPR-Cas systems, we show how the social interactions between the acyl-homoserine lactone (AHL)-QS signal-blind mutants (ΔlasRrhlR) and the CRISPR-Cas mutants are affected by phage exposure and nutrient availability. We demonstrate that media conditions and phage exposure alter the resistance and relative fitness of ΔlasRrhlR and CRISPR-Cas mutants while tipping the fitness advantage in favor of the QS signal-blind mutants under nutrient-limiting conditions. We also show that the AHL signal-blind mutants are less selected by phages under QS-inducing conditions than the CRISPR-Cas mutants, whereas the mixed population of the CRISPR-Cas and AHL signal-blind mutants reduce phage infectivity, which can improve survival during phage exposure. Our data reveal that phage exposure and nutrient availability reshape the population dynamics between the ΔlasRrhlR QS mutants and CRISPR-Cas mutants, with key indications for cooperation and conflict between the strains