Washington — NIOSH and the National Hearing Conservation Association are accepting nominations for the 2019 Safe-in-Sound Excellence in Hearing Loss Prevention Award.

Washington — NIOSH, along with the National Hearing Conservation Association and the Council for Accreditation in Occupational Hearing Conservation, has extended to Aug. 15 the nomination deadline for the 2023 Safe-in-Sound Excellence in Hearing Loss Prevention Award.

Washington — The Chemical Safety Board has extended to Dec. 31 its deadline for comment on a recent initiative that seeks to better understand why efforts to manage and control combustible dust hazards “have often failed” to prevent explosions.

Washington — OSHA has pushed to Nov. 13 the deadline for comment on its proposal to allow workers to designate someone who doesn’t work for their employer to represent them during OSHA “walkaround” inspections.

Washington — In response to multiple stakeholder requests, OSHA has extended until Oct. 28 the comment period on a proposed rule that would revise the agency’s standards on occupational exposure to lead in general industry and construction.

Astronomers at the University of Warsaw in Poland discovered a new Cepheid variable star. The newly discovered star, designated OGLE-GD-CEP-1884, has the longest pulsation period known for any variable of its type in the Milky Way Galaxy, an article published on the arXiv preprint server says. Cepheids are yellow giant and supergiant stars that change their brightness over time as a result of regular stellar pulsations. Given that their pulsation periods are closely related to their luminosity, astronomers use these stars to measure interstellar and intergalactic distances. Classic Cepheids, also known as Type I Cepheids, pulsate with highly regular periods ranging from a few days to months.

Following the work of Day & Hawthorne [Acta Cryst. (2022), A78, 212–233] and Day et al. [Acta Cryst. (2024), A80, 258–281], the program GraphT–T has been developed to embed graphical representations of observed and hypothetical chains of (SiO4)4− tetrahedra into 2D and 3D Euclidean space. During embedding, the distance between linked vertices (T–T distances) and the distance between unlinked vertices (T⋯T separations) in the resultant unit-distance graph are restrained to the average observed distance between linked Si tetrahedra (3.06±0.15 Å) and the minimum separation between unlinked vertices is restrained to be equal to or greater than the minimum distance between unlinked Si tetrahedra (3.713 Å) in silicate minerals. The notional interactions between vertices are described by a 3D spring-force algorithm in which the attractive forces between linked vertices behave according to Hooke's law and the repulsive forces between unlinked vertices behave according to Coulomb's law. Embedding parameters (i.e. spring coefficient, k, and Coulomb's constant, K) are iteratively refined during embedding to determine if it is possible to embed a given graph to produce a unit-distance graph with T–T distances and T⋯T separations that are compatible with the observed T–T distances and T⋯T separations in crystal structures. The resultant unit-distance graphs are denoted as compatible and may form crystal structures if and only if all distances between linked vertices (T–T distances) agree with the average observed distance between linked Si tetrahedra (3.06±0.15 Å) and the minimum separation between unlinked vertices is equal to or greater than the minimum distance between unlinked Si tetrahedra (3.713 Å) in silicate minerals. If the unit-distance graph does not satisfy these conditions, it is considered incompatible and the corresponding chain of tetrahedra is unlikely to form crystal structures. Using GraphT–T, Day et al. [Acta Cryst. (2024), A80, 258–281] have shown that several topological properties of chain graphs influence the flexibility (and rigidity) of the corresponding chains of Si tetrahedra and may explain why particular compatible chain arrangements (and the minerals in which they occur) are more common than others and/or why incompatible chain arrangements do not occur in crystals despite being topologically possible.

This article describes the diffraction pattern (2-periodic Fourier transform) from the vertices of a large patch of the recently discovered `Spectre' tiling – a strictly chiral aperiodic monotile. It was reported recently that the diffraction pattern of the related weakly chiral aperiodic `Hat' monotile was 2-periodic with chiral plane-group symmetry p6 [Kaplan et al. (2024). Acta Cryst. A80, 72–78]. The diffraction periodicity arises because the Hat tiling is a systematic aperiodic deletion of vertices from the 2-periodic hexagonal mta tiling. Despite the similarity of the Hat and Spectre tilings, the Spectre tiling is not aligned with a 2-periodic lattice, and its diffraction pattern is non-periodic with chiral point symmetry 6 about the origin.

The results of a study of the structural and reflective characteristics of short-period multilayer X-ray mirrors based on Mo/B4C at wavelengths 1.54 Å, 9.89 Å and 17.59 Å are presented. The period of the samples varied in the range 8–35 Å. The average widths of the interfaces were ∼3.5 and 2.2 Å at one and the other boundaries, with a tendency for weak growth with any decrease in the period. The interlayer roughness was ∼1 Å. The research results indicate promising prospects for the use of multilayer Mo/B4C mirrors for synchrotron applications.

Understanding the symmetries described by subperiodic groups – frieze, rod and layer groups – has been instrumental in predicting various properties (band structures, optical absorption, Raman spectra, diffraction patterns, topological properties etc.) of `low-dimensional' crystals. This knowledge is crucial in the tailored design of materials for specific applications across electronics, photonics and materials engineering. However, there are materials that have the property of being periodic only in one direction and whose symmetry cannot be described by the subperiodic rod groups. Describing the symmetry of these materials necessitates the application of line group theory. This paper gives an overview of subperiodic groups while briefly introducing line groups in order to acquaint the crystallographic community with these symmetries and direct them to pertinent literature. Since line groups are generally not sub­periodic, they have thus far remained outside the realm of symmetries traditionally considered in crystallography, although there are numerous `one-dimensional' crystals (i.e. monoperiodic structures) possessing line group symmetry.

We explore a special class of periodic graphs, ladder graphs, whose edges can coincide when embedded vertices are moved. Many of these exhibit additional non-crystallographic graph symmetries.

Young adults ages 18-26 should be viewed as a separate subpopulation in policy and research, because they are in a critical period of development when successes or failures could strongly affect the trajectories of their lives, says a new report from the Institute of Medicine and National Research Council.

CosmicBeetle, after improving its own ransomware, tries its luck as a RansomHub affiliate

President Joe Biden asked businesses to voluntarily move forward with the administration’s Covid-19 vaccine and testing requirements.

The New Mexico Workers' Compensation Administration is accepting public comments on the 2025 fee schedule and billing instructions. Written public comments will be accepted until the close of business on Nov. 1 and should be…

The California Division of Workers’ Compensation opened a second 15-day comment period on a proposal to incorporate Medi-Cal’s reimbursement rules into its pharmacy fee schedule. In addition to technical corrections, the…

A divided Michigan Court of Appeals upheld the dismissal of a tort claim saying the injured worker agreed to a shorter statute of limitations in a contract he signed as…

Allow experienced drivers from war-torn countries to skip driving-test waiting period similar to other newcomers in OntarioToronto, ON – Ontario’s Ministry of Transportation should revise its policy and allow experienced drivers from war-torn countries to skip the one-year waiting period before their final driving tests — an exemption available to other newcomers in Ontario as well […]

The HVACR industry was initially surprised by a date-of-install requirement, mandating installation of certain equipment by January 1, 2025, but EPA extended sell-through period to January 1, 2026.

The EPA initially faced backlash from the industry regarding the sell-through mandate for certain HVAC systems. The Agency revised the provision by allowing one additional year, until January 1, 2026.

Advocates are working to overcome patriarchal structures worldwide that deny menstruating people dignity, access, and agency.

Room 29, Parliament Buildings

Resolution 87 - (Hammamet, 2016) - Participation of the ITU Telecommunication Standardization Sector in the periodic review and revision of the International Telecommunication Regulations

Test signals to be used by the broadcasting organizations during the preparatory period

Measurements to be made before the line-up period that precedes a television transmission

Definition and duration of the line-up period and the preparatory period

Definition and duration of the line-up period and the preparatory period

Measurements to be made by the broadcasting organizations during the preparatory period

Measurements to be made during the line-up period that precedes a sound-programme transmission

Tests to be made during the line-up period that precedes a television transmission

Tests to be made during the line-up period that precedes a television transmission

Ireland-based Orreco has developed a new app to help athletes optimise their performances.

Read more: Breakthrough app aims to smash taboos about training during your period

El único periodista que ha dirigido el carrusel de las cuatro grandes radios decidió, hace cinco años, escapar de Madrid y ser feliz en Gijón. Su diagnóstico de la profesión es duro: "La información deportiva está contaminada" Leer

El director general recurrió a la consultora Campo y Ochandiano para proceder a la selección del ex director de Deia y de Radio Euskadi. Camino abandonó el Gobierno vasco el pasado mes de julio tras trabajar como asesor de las consejeras Beatriz Artolazabal y Nerea Melgosa Leer

El jurado ha destacado de Carlos Franganillo "su trayectoria como referencia del periodismo televisivo en España", así como "su independencia, rigor, capacidad para innovar los formatos periodísticos de la televisión y su vocación por el reporterismo" Leer

El reportaje narra la historia de una pareja de personas ciegas y su hija, sin discapacidad visual, y explica cómo crece una niña en el seno de una familia así Leer

Trabajó en la sección de Nacional de EL MUNDO y en 2007 arrancó su carrera de escritor con Carta de ajuste Leer

Militantes del grupo neofascista Casa Pound celebraban una fiesta y se acercaron el periodista Andrea Joly, que estaba grabando con su teléfono móvil, y le preguntaron: "¿Eres de los nuestros?" Leer

Manolín, como era conocido, pasó toda su vida profesional en Efe, buena parte de ella durante la Transición, cubriendo la actividad parlamentaria y política del país y siguiendo también a la Casa Real Leer

El ex editor jefe de Stand News, Chung Pui-kuen, y el ex editor en funciones, Patrick Lam, fueron arrestados en 2021 tras declararse inocentes del cargo de conspiración Leer

Angelina Jolie, Nicole Kidman, Winona Ryder y Willem Dafoe ya han llegado al certamen, donde aún se espera la llegada de Brad Pitt, George Clooney o Pedro Almodóvar Leer

El reportero estrella de 'The New Yorker' publica en España 'Cabeza de serpiente', una crónica sobre el poder de la mafia china y el lado más turbio del sueño americano Leer

La también guionista y locutora ha fallecido a causa de un colangiocarcinoma, una afección que provoca la formación de células cancerosas en las vías biliares Leer

Las comunicadoras han sido condenadas por "colusión contra la seguridad nacional" y por "propaganda contra el sistema" Leer