United Nations (1992),

References are listed under the heading(s) of the chapter(s) in which they are cited. The idea in duplicating some references in this way is to enable readers interested in one particular chapter, for example the informal sector, to be readily able to identify all the references made in that chapter. The 1993 SNA and two compendia are listed in the first section labelled General. The lists also include some references that are not explicitly cited in the Handbook but that provide useful background material or elaboration of the text. The documents are in English except where otherwise noted

Fatigue properties of Ti6Al4V cellular specimens fabricated via SLM: CAD vs real geometry

Abstract Fully dense titanium alloy implants have long been used for the replacement and stabilization of damaged bone tissue. Nevertheless, they can cause stress shielding which brings to a loss of bone mass. Additive manufacturing (AM) allows obtaining highly porous cellular structures with a wide range of cell morphologies to tune the mechanical properties to match that of the patient's bone. In this work, the fully reversed fatigue strength of cellular specimens produced by Selective Laser Melting (SLM) of Ti-6Al-4V alloy was measured. Their structures are determined by cubic cells packed in six different ways and their elastic modulus is roughly 3GPa to match that of trabecular bone. Part of the specimens was left as sintered and part treated by Hot Isostatic Pressing (HIP). The fatigue resistance of such AM parts can be affected by surface morphology, geometrical accuracy as well as internal defects. Micro X-ray computed tomography (CT) was used in this work to compare the geometry of the produced specimens with the CAD model and to carry out residual stress measurements using the Plasma FIB-SEM-DIC micro-hole drilling method

SARS-CoV-2 structural coverage map reveals viral protein assembly, mimicry, and hijacking mechanisms

We modeled 3D structures of all SARS-CoV-2 proteins, generating 2,060 models that span 69% of the viral proteome and provide details not available elsewhere. We found that ˜6% of the proteome mimicked human proteins, while ˜7% was implicated in hijacking mechanisms that reverse post-translational modifications, block host translation, and disable host defenses; a further ˜29% self-assembled into heteromeric states that provided insight into how the viral replication and translation complex forms. To make these 3D models more accessible, we devised a structural coverage map, a novel visualization method to show what is-and is not-known about the 3D structure of the viral proteome. We integrated the coverage map into an accompanying online resource (https://aquaria.ws/covid) that can be used to find and explore models corresponding to the 79 structural states identified in this work. The resulting Aquaria-COVID resource helps scientists use emerging structural data to understand the mechanisms underlying coronavirus infection and draws attention to the 31% of the viral proteome that remains structurally unknown or dark

Hamiltonian Dynamics and the Phase Transition of the XY Model

A Hamiltonian dynamics is defined for the XY model by adding a kinetic energy term. Thermodynamical properties (total energy, magnetization, vorticity) derived from microcanonical simulations of this model are found to be in agreement with canonical Monte-Carlo results in the explored temperature region. The behavior of the magnetization and the energy as functions of the temperature are thoroughly investigated, taking into account finite size effects. By representing the spin field as a superposition of random phased waves, we derive a nonlinear dispersion relation whose solutions allow the computation of thermodynamical quantities, which agree quantitatively with those obtained in numerical experiments, up to temperatures close to the transition. At low temperatures the propagation of phonons is the dominant phenomenon, while above the phase transition the system splits into ordered domains separated by interfaces populated by topological defects. In the high temperature phase, spins rotate, and an analogy with an Ising-like system can be established, leading to a theoretical prediction of the critical temperature $T_{KT}\approx 0.855$.Comment: 10 figures, Revte

Integração de dados de georeferenciamento e dados genéticos para o manejo da biodiversidade de recursos genéticos de ovinos no Brasil.

Existem relativamente poucas coleções de germoplasma/bancos de DNA de animais domésticos de produção distribuídos pelo Brasil. Estas coleções precisam de estudos básicos, a fim de atender as demandas futuras no país e até do mundo. O objetivo deste trabalho foi realizar uma análise crítica de um Banco de DNA a partir de dados espaciais (dados georreferenciados) e genéticos em relação aos locais de origem a partir de 3518 amostras de DNA originados de 17 diferentes grupos genéticos ou raças de ovelhas do Banco de DNA e Tecidos localizado no Laboratório de Genética Animal da Embrapa Recursos Genéticos e Biotecnologia. O georeferenciamento mostrou que nem todos os grupos genéticos têm amostras no banco e as coletas foram concentradas no núcleo de conservação. Apenas 21% dos estados com uma determinada raça têm amostras no banco de genes. O número médio de animais amostrados por coleta foi de 32, enquanto a distância média entre pontos de coleta e núcleos de conservação foi 550 km. A raça Somalis Brasileira foi coletada apenas no seu núcleo de conservação. Não foram coletadas amostras para a raça Cariri. Apenas duas fazendas e uma raça no banco são da região norte. Dos 27 estados brasileiros, 13 proveram amostras ao banco de germoplasma, o que mostra a necessidade de coletas em rebanhos fora do sistema oficial de rebanhos de conservação para garantir que os estudos realizados utilizando este germoplasma não são tendenciosos. Sugestões são dadas para a melhoria da quantidade e diversidade de amostras do referido Banco de DNA