Pollen Grain Counting Using a Cell Counter

The number of pollen grains is a critical part of the reproductive strategies in plants and varies greatly between and within species. In agriculture, pollen viability is important for crop breeding. It is a laborious work to count pollen tubes using a counting chamber under a microscope. Here, we present a method of counting the number of pollen grains using a cell counter. In this method, the counting step is shortened to 3 min per flower, which, in our setting, is more than five times faster than the counting chamber method. This technique is applicable to species with a lower and higher number of pollen grains, as it can count particles in a wide range, from 0 to 20,000 particles, in one measurement. The cell counter also estimates the size of the particles together with the number. Because aborted pollen shows abnormal membrane characteristics and/or a distorted or smaller shape, a cell counter can quantify the number of normal and aborted pollen separately. We explain how to count the number of pollen grains and measure pollen size in Arabidopsis thaliana, Arabidopsis kamchatica, and wheat (Triticum aestivum)

Nucleation process in the Burridge-Knopoff model of earthquakes

Nucleation process of the one-dimensional Burridge-Knopoff model of earthquakes obeying the rate- and state-dependent friction law is studied both analytically and numerically. The properties of the nucleation dynamics, the nucleation lengths and the duration times are examined together with their continuum limits.Comment: Title changed, one figure (previous Fig.2) omitted, several references (new Refs.5-8,21,24-28) added, and two eqs. (new eqs.1,5) added. Text expanded considerably, especially the part explaining the relation of the model to the elastic continuum model. To appear in Europhys. Letter

西日本小型底曳網の力学的研究

The mechanical characteristics of a four-seam trawl net being used in the west Japan district was studied on the basis of its construction. The authors, in this report, watched especially on the wing length of the net. It was found that when the transversal distance between the danlenos exceeds the length of 13.6 cm in the model net and 408 cm in the practical net, the force acting on the net becomes smaller as the wing becomes longer at the towing speeds that are given in the practical fishing

Nucleocytoplasmic transport of Alp7/TACC organizes spatiotemporal microtubule formation in fission yeast

Ran GTPase activates several target molecules to induce microtubule formation around the chromosomes and centrosomes. In fission yeast, in which the nuclear envelope does not break down during mitosis, Ran targets the centrosomal transforming acidic coiled-coil (TACC) protein Alp7 for spindle formation. Alp7 accumulates in the nucleus only during mitosis, although its underlying mechanism remains elusive. Here, we investigate the behaviour of Alp7 and its binding partner, Alp14/TOG, throughout the cell cycle. Interestingly, Alp7 enters the nucleus during interphase but is subsequently exported to the cytoplasm by the Exportin-dependent nuclear export machinery. The continuous nuclear export of Alp7 during interphase is essential for maintaining the array-like cytoplasmic microtubule structure. The mitosis-specific nuclear accumulation of Alp7 seems to be under the control of cyclin-dependent kinase (CDK). These results indicate that the spatiotemporal regulation of microtubule formation is established by the Alp7/TACC–Alp14/TOG complex through the coordinated interplay of Ran and CDK

A Survey of the Role of Audit Committees in Promoting Corporate Governance and Accountability in Constituency Development Fund Management: A Case Study of Nairobi Province, Kenya

The purpose of this study is to present a case for the need for audit committee in Constituency Development Fund to promote corporate governance and accountability in constituency development fund management in Nairobi Province, Kenya. The study provides an analysis and critique of the extent of engagement research in the field of corporate governance and accountability in constituency Development Fund management and present case for further research that may be directed to outside Nairobi province. The study found that the extent of literature in the field of corporate governance and accountability and reporting in contrast to the field to management CDF in Nairobi had largely ignored the practice within CDF organizations. The study arguesthat CDF can benefit from the methodological and theoretical insights of audit committee and other disciplines. The study suggests where further contributions might be made by future research endeavors engaging with audit committees with organizations. Engaging audit committee in CDF governance and accountability has the potential to improve theorizing practice and the sustainability performance with organizations. Drawing on the methods and theories of other disciplines and the papers in the special issues (of audit committee) the study presents away forward for researchers engaging with audit committees in organizational practicing corporate governance and accountability