The positive minded Education Minister, Nicolette Henry, on Saturday visited a few schools around Georgetown and on the East Coast of Demerara to assess their readiness for the new school year scheduled to begin on Monday, September 3.This was according to a statement issued by the Ministry which detailed a report of each of the schools’ readiness.Education Minister Nicolette Henry being briefed by Special Projects Officer, Ron Eastman on the ongoing works at Cummings Lodge SecondaryThe Minister’s visit comes at a time where education officials across the country are sitting at the edge of their seats, with their fingers crossed since more than 7000 teachers are expected to go on strike from today.The proposed strike is expected to start one week before the new school term begins, during schools’ pre-term activities. According to the President of the Guyana Tachers’ Union, Mark Lyte, if head teachers are going to be on strike then they need to hand over the school keys to the Department of Education before actions commence.Meanwhile, some temporary teachers are of the view that if they were to go on strike, they will be replaced by trained teachers who are waiting to get into the system. Lyte added that they could go to work and still be laid off because they are temporary.Minister Henry did say measures will be put in place if the teachers strike. Some of those measures she outlined are working a shift system in schools and having volunteers take over schools among others.However, on Friday, Lyte said he finds the Minister’s proposal hilarious.“I don’t know if the Minister understood what it took for us to have teachers. We are not replaceable. Let us see what this emergency plan is because somebody will have to conduct my orientation when the parents show up on Monday; me nor none of my teachers will be in school,” Lyte said after being assured that many of the head teachers had already handed in their keys to the Department of Education.Lyte was on Friday absent from the conciliation talks, which were organised by the Social Protection Ministry’s Department of Labour for the Union and the Education Ministry to meet and discuss a way forward.According to Lyte, he was unable to attend the meeting since he was out of the region on duty and only received an official invite on Friday morning.He indicated that he would have received yet another invitation for a meeting with the same parties, which is now expected to be held on August 28; day two into the strike action.Lyte said he is yet to confirm his attendance to that meeting.The GTU has rejected Government’s request for teachers to agree to a debunching payoff of $200 million for 2018/19. Lyte said the Union similarly rejected the $700 million cap that was placed on salary increases which was for 2018 only. Government also wants the clothing allowance to remain at $8000; a figure Lyte said was given in 2011.He said, too, that for the Whitley Council Leave, teachers still have to wait four years before getting their one month off, even though the GTU appealed for three years. The Union is seeking 40 per cent salary increases for its 7000 members.
Light-controlling artificial diamond structures could lead to optical computers This scanning electron micrograph image shows an array of milled colloidal spheres on the surface of an artificial opal. Image credit: Léon Woldering, et al. As the scientists explain in their study, most nanotechnologies involve spherical nanoparticles, so different shapes—such as the beads—could offer new avenues of technology with their structural flexibility. In the case of photonic crystals, for example, a single modified colloidal particle inside the photonic crystal could act as an optical cavity to control light.“Our motivation with these nanoparticles is the fabrication of an optical cavity in a three-dimensional photonic crystal by adding additional opal layers to the structures we fabricated, and subsequent inversion of the crystal,” said Woldering. “The inverse opal will be a silicon or titanium dioxide structure. “In order to study the confinement of light, we plan to probe the emission from quantum dots placed near or inside the optical cavity,” he continued. “Alternatively, if the crystal surrounding a cavity in which light is confined is switched by modifying the refractive index, we may be able to release the confined photon at will. This will allow the fabrication of a photon-on-demand light source. A cavity could also act as a highly sensitive on-chip sensor of tiny amounts of matter in, e.g., chemical, biological, or even life-science issues.”Still other applications, as Woldering et al. explain, could emerge in the development of solar cells with highly efficient light transmitters. Also, these opals could provide a resource for plasmonics devices, such as computer chips, and even optical microscopes that can focus on objects smaller than a wavelength of light.Citation: Woldering, Léon A., Otter, A.M. (Bert), Husken, Bart H., and Vos, Willem L. “Focused ion beam milling of nanocavities in single colloidal particles and self-assembled opals.” Nanotechnology 17 (2006) 5717-5721.By Lisa Zyga, Copyright 2006 PhysOrg.com One of the most rapidly advancing areas of applied nanotechnology involves photonic crystals. With their ability to control light propagation, photonic crystals are predicted to replace other methods for devices such as display lasers, circuits and quantum computers. Although complex manufacturing has stunted their fabrication, scientists have recently found a new technique to control the size, shape and chemical flexibility of opals, a type of photonic crystal, to the smallest degree yet. Explore further “The essence of our work is that we are able to control the shape of individually addressed nanoparticles inside artificial opals,” Léon Woldering, coauthor of the study, told PhysOrg.com. “We fabricate nanocavities in individual colloidal particles, and can change the position of these cavities and tune the diameter with nanometer precision. We thus realize a kind of nano-donut, or nano-bead.”Woldering, and the rest of his group from the Netherlands, used a technique called focused ion beam milling (FIB) to “drill” (or “mill”) 80-nm-wide cavities into single colloids on artificial opals. The individual colloids, about 100 nm in radius, were grown through a self-assembly technique from silicon dioxide colloidal spheres. In their investigation, the scientists milled cavities for a duration between five and 30 seconds, and found that longer milling times corresponded to larger cavities. “Not only is the nanotechnology to make these cavities extremely interesting in itself, but also the method we developed to mill these structures on a non-conducting substrate is novel and expands the possibilities of FIB in general,” said Woldering.Usually, the FIB technique does not have a reputation for precise high resolution applications such as the fabrication of the nanobeads here. In the past, techniques using electron beams and laser beams could create large modifications in opal films, but not with this great detail. Although Woldering et al. encountered challenges due to the small, non-conductive opals made of easily loosened elements, they still succeeded in creating much smaller modifications than previous techniques.“FIB on an insulating substrate is a challenge in general,” explained Woldering. “In our case, even more so, because milling on our substrates causes the individual colloidal spheres to charge, after which they repel each other and are ejected, thereby destroying the crystal. We were able to promote the diffusion of charges away from the milled area by deposition of a conducting carbon layer on top of the substrate, and by adapting an intermittent milling procedure. In this fashion, the breakdown of the photonic crystal was prevented, and we were able to obtain our nanocavities.” This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Tiniest modified opals ready to manipulate light flow as photonic crystals (2006, November 29) retrieved 18 August 2019 from https://phys.org/news/2006-11-tiniest-opals-ready-photonic-crystals.html