Cytological Observations and Bulked-Segregant Analysis Coupled Global Genome Sequencing Reveal Two Genes Associated with Pollen Fertility in Tetraploid Rice

Neo-tetraploid rice with high fertility is a useful germplasm for polyploid rice breeding, which was developed from the crossing of different autotetraploid rice lines. However, little information is available on the molecular mechanism underlying the fertility of neo-tetraploid rice. Here, two contrasting populations of tetraploid rice, including one with high fertility (hereafter referred to as JG) and another with low fertility (hereafter referred to as JD), were generated by crossing Huaduo 3 (H3), a high fertility neo-tetraploid rice that was developed by crossing Jackson-4x with 96025-4x, and Huajingxian74-4x (T452), a low fertility autotetraploid rice parent. Cytological, global genome sequencing-based bulked-segregant (BSA-seq) and CRISPR/Cas9 technology were employed to study the genes associated with pollen fertility in neo-tetraploid rice. The embryo sacs of JG and JD lines were normal; however, pollen fertility was low in JD, which led to scarce fertilization and low seed setting. Cytological observations displayed low pollen fertility (25.1%) and approximately 31.3 and 27.2% chromosome lagging at metaphase I and II, and 28.8 and 24.8% chromosome straggling at anaphase I and II in JD, respectively. BSA-seq of F_2–3 generations and RNA-seq of F₄ generation detected a common fragment, i.e., 18,915,234–19,500,000, at chromosome 7, which was comprised of 78 genes associated with fertility. Among 78 genes, 9 genes had been known to be involved in meiosis and pollen development. Two mutants ny1 (LOC_Os07g32406) and ny2 (LOC_Os07g32040) were generated by CRISPR/Cas9 knockout in neo-tetraploid rice, and which exhibited low pollen fertility and abnormal chromosome behavior. Our study revealed that two unknown genes, LOC_Os07g32406 (NY1) and LOC_Os07g32040 (NY2) play an important role in pollen development of neo-tetraploid rice and provides a new perspective about the genetic mechanisms of fertility in polyploid rice.     

Crops that feed the World 1. Yams

Yam (Dioscorea sp.) is a major source of food for millions of people in tropical and sub-tropical regions, especially in West and Central Africa where at least 60 million people depend on it. It is also a major source of income and an integral part of socio-cultural life. In addition to their food uses, some Dioscorea species are exploited for pharmaceutical products. Yam cultivation is undergoing intensification in many production zones leading to challenges in the management of soil fertility and structure, increasing pressure of diseases and pests (including weeds), and requirements for new varieties better suited to the changing biophysical and socio-economic circumstances. Greater attention also needs to be paid to raising labor productivity and improving access of producers to affordable and higher quality planting materials. These challenges, and the opportunities associated with the biology of the crop, need to be addressed more systematically and earnestly through collaborative research and development, and effective dissemination of the results to relevant stakeholders. The increasing capacity for, and international collaboration in, research and development on yam augur well for the future of the crop and the millions of people who depend on it.     

In-plane magnetic anisotropy and temperature dependence of switching field in (Ga, Mn) as ferromagnetic semiconductors

We explore the magnetic anisotropy of GaMnAs ferromagnetic semiconductor by Planar Hall Effect (PHE) measurements. Using low magnitude of applied magnetic field (i.e., when the magnitude H is smaller than both cubic Hc and uniaxial Hu anisotropy field), we have observed various shapes of applied magnetic field direction dependence of Planar Hall Resistance (PHR). In particular, in two regions of temperature. At T < Tc/2, the "square-shape" signal and at T > Tc/2 the "zigzag-shape" signal of PHR. They reflect different magnetic anisotropy and provide information about magnetization reversal process in GaMnAs ferromagnetic semiconductor. The theoretical model calculation of PHR based on the free energy density reproduces well the experimental data. We report also the temperature dependence of anisotropy constants and magnetization orientations. The transition of easy axis from biaxial to uniaxiale axes has been observed and confirmed by SQUID measurements.     

Computer-Based Application for the Processing of Clients' Requirements

This paper extends previous work on the use of quality function deployment for client requirements processing in construction. It describes a computer-based application, ClientPro, which implements a quality-function-deployment-based model for the definition, analysis, and translation of client requirements into solution-neutral design specifications. The methodology, development, operation, and evaluation of the prototype are discussed, and it is concluded that ClientPro is useful in facilitating the systematic definition, analysis, and mapping of client requirements to design specifications. It also provides for the incorporation and prioritization of the perspectives represented by clients, the determination of the relative importance of their requirements, and the early consideration of life-cycle issues affecting a facility. Thus, it can contribute to the ultimate satisfaction of the requirements of construction clients.     

Prototype System for Knowledge Problem Definition

Attitudes to knowledge management (KM) have changed considerably as organizations are now realizing its benefits. Implementation, however, has been facing serious difficulties attributed either to not being able to anticipate the barriers when planning KM strategies or to using inappropriate methods and tools for implementation. These difficulties are more critical in construction due to the fragmented nature of the industry. This paper suggests that proper definition of a KM problem at the early stages of developing the KM initiatives will result in better control over the KM barriers. A methodology for identifying KM problems within a business context is then introduced. The methodology is encapsulated into a prototype software system, which facilitates its deployment in organizations and provides online help facilities. The methodology, development, operation, and evaluation of the prototype are described. The paper concludes that the prototype offers considerable potential for delivering a clarified KM problem and a distilled set of issues for an organization to address. This represents a significant first step in any KM initiative.     

Practical system for the direct measurement of magneto-caloric effect by micro-thermocouples

A system for direct measurements of the magneto-caloric effect (MCE) exploits a rapid transport of a sample into or from magnetic field in permanent Halbach-type (1 T) or superconducting (4.7 T) magnets. Time dependence of induced changes of the sample temperature, ΔT(t), is detected directly by the differential Cu-Constantan-Cu micro-thermocouples with time steps of 300 ms. A sample placed inside an evacuated simple LN(2) cryostat is either totally isolated (adiabatic conditions) or partly connected with the copper sample holder (non-adiabatic conditions). The last arrangement (a model of the Brayton cycle) is used to simulate an application of MCE in refrigeration techniques. The relations describing ΔT(t) that allow an analysis of MCE of the studied materials are based on the general cooling law. The effect of the first-order magnetic transition on MCE of selected sample is also demonstrated by non-standard ΔT(t) curves measured in the last mentioned experimental arrangements.     

Laser Surface Modification of Carbon Fiber Reinforced Composites

The removal of top resin layer is an essential task prior to adhesive bonding of carbon fiber reinforced polymer (CFRP) composites. This paper investigates the technical feasibility of using a low power continuous wave carbon dioxide laser for removing the top resin layer of CFRP without damaging the underlying fiber. The operating window and damaging threshold were experimentally determined. Irradiating the CFRP surface at a power of 14 W, scanning speed of 880 mm/sec, and a beam overlap of 25% provides an optimal thermal condition for removal of top resin layer. A finite element model was used to explain the removal mechanisms.