In this article we study the deformations of hyperelliptic polarized varieties (X, L) of dimension m and sectional genus g such that the image Y of the morphism ϕ induced by |L| is smooth. If L m < 2g − 2, it is known that, by adjunction and the Clifford's theorem, any deformation of (X, L) is hyperelliptic. Thus, we focus on when L m = 2g − 2 or L m = 2g. We prove that, if (X, L) is Fano-K3, then, except when Y is a hyperquadric, all deformations of (X, L) are again hyperelliptic (if Y is a hyperquadric, the general deformation of ϕ is an embedding). This contrasts with the situation of hyperelliptic canonical curves and hyperelliptic K3 surfaces. If L m = 2g, then we prove that, in most cases, a general deformation of ϕ is a finite morphism of degree 1. This provides interesting examples of degree 2 morphisms that can be deformed to morphisms of degree 1. We extend our results to so-called generalized hyperelliptic polarized Fano, Calabi-Yau and general type varieties. The solutions to these questions are closely intertwined with the existence or non existence of double structures on the algebraic varieties Y . We address this matter as well.
El cobre se obtiene principalmente a partir de los sulfuros de cobre, mediante procesos clásicos de flotación y pirometalúrgicos, siendo Chile el mayor productor de cobre en el mundo. En nuestro país existen siete fundiciones de cobre que generan grandes volúmenes de escoria. Este trabajo presenta los resultados obtenidos de la flotación de cobre de escorias del horno de reverbero (HR) y del convertidor Teniente (CT) de la Fundición Hernán Videla Lira-Paipote. Así, mediante pruebas de flotación rougher, a escala de laboratorio, se determinó que la granulometría, para ambos casos, corresponde a 70% menor a 74 µm, lográndose recuperaciones de 59,2% escoria HR y 86,8% para la escoria del CT, cuyas leyes de cobre en el concentrado fueron de 3,7% y 23,6% respectivamente. Las dosis de reactivos utilizados fueron 40 g/t de F-703 como colector y 30 g/t de H-70 como espumante. Los tiempos óptimos de flotación de las etapas rougher y cleaner, de ambas escorias, se determinaron mediante cinéticas de flotación. Finalmente se realizaron pruebas a nivel industrial con los resultados de laboratorio, alcanzándose una ley de 18,2% de cobre (recuperación de 56,1%) para escoria HR, mientras que para la escoria CT se obtuvo una ley de 39,1% de cobre con una recuperación de 91,4% PALABRAS-CLAVE: escoria de cobre, recuperación, flotación.
Biological agents as weapons of agro‐crime or agro‐terrorism pose threats to peace and economic stability. Such agents pre‐exist worldwide as hazards, adversely affecting animal health, as well as imposing substantial burdens on many nations. Few studies have quantified the global risks and vulnerabilities of countries and regions to potential terrorist or criminal operations targeting animal health. We present here a risk‐based mutual insurance premium framework for animal health outcomes built upon the World Organisation for Animal Health (WOAH) quantitative risk assessment paradigm. Our objective was to generate dimensionless and relative domain indices related to release and exposure for several biological factors, as well as to assess the preparedness and response ability of each country. We also considered disease‐specific measures relating to pathogens, targeted animal populations, the ongoing disease situation, within‐ and among‐country peace or conflict, disease‐specific control measures, and the availability of technical tools and personnel for successful disease management. National economic, political, and research and development competencies were used to assess each WOAH Member's potential for resilience. We formulated indices of vulnerability for 25 WOAH Members selected from five worldwide regions; initially, against four transboundary infectious animal diseases that target diverse animal species. We developed these indices using variables obtained from public databases arising from multiple intergovernmental organizations. Subsequently, we compared the relative vulnerability indices among countries for each given disease using three different index building methods: arithmetic mean, distance matrix, and principal component analysis (PCA). The PCA‐based approach provided the greatest ability to discriminate among the components and among countries and regions. Due to its transparency and reliance on publicly available datasets, the risk premium framework proposed herein may readily be adjusted by policymakers and agencies and utilized to improve risk management strategies against agro‐crime or agro‐terror events, as well as for unintentional disease introductions.
Burn prevention information may be inadequate or inaccessible to communities with non-English language preference. Our objective was to systematically analyze the content accuracy, website quality, and readability of online Spanish information for burn prevention in the home and compare it to English websites. We collected the top ten burn prevention results from a search on Google, Bing, and Yahoo using a list of Spanish key terms. Using recommendations from national organizations and a burn care expert team, content accuracy was evaluated for each website. We assessed website quality following the “Health on the Net” Code of Conduct. Readability was scored by averaging five validated readability tests for the Spanish language. After using the same protocol, a comparison was made with English websites as a control. Once duplicates and non-relevant search results were removed, 23 Spanish websites were assessed. Out of 21 possible points for content accuracy, the top website scored 14 (67%) and the average score was 6.6 (31%). For website quality, the average score was 50%. The average grade level needed to read the websites was 8.6. Compared to English, Spanish websites were less accurate (31% vs 41%), harder to read (9.8 vs 7.8), but were of higher website quality (50% vs 43%). Online burn prevention information in Spanish is often inaccurate, incomplete, and inferior to available English language websites. We propose a call to action to increase the quality of online burn prevention material available in Spanish.
Copper slag flotation was studied on an industrial scale at a concentrator plant in the region of Atacama, Chile. This study consisted of the physical, chemical, and mineralogical characterization of the copper slag, along with preliminary flotation tests. This article focuses on industrial flotation, which consisted of two oneyear campaigns (2016 and 2017). The first campaign was carried out using an existing copper slag flotation circuit in the plant. During the second campaign (2017), a circuit for sulfide ore flotation with an additional columnar flotation cleaning stage was evaluated. Results showed an improvement in metallurgical parameters on the second campaign (including improvements in processing capacity, concentrate copper grade, and metallurgical recovery). From the industrial copper slag flotation campaigns, it was concluded that it is possible to obtain a commercialquality copper concentrate, suitable for further processing in a copper smelter. This mitigates certain environmental impacts of copper processing.
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