93 research outputs found
GEOLOGICAL AND MINERALOGICAL CHARACTERIZATION OF LA TOSCA DEPOSIT (VETAS, SANTANDER, COLOMBIA): IMPLICATIONS FOR MINERAL PROCESSING OF GOLD-SILVER ORES
La Tosca, a gold-silver hydrothermal deposit is located 1 Km Northwest Vetas (Santander, Colombia) and geologically, it is part of the Santander Massif. Gold occurs as free grains, included or associated to ilmenite, galena and in veins with a preferred orientation N40W. Other ore minerals are pyrite, chalcopyrite, silver, pyrrhotite and magnetite. Wall rocks comprises quartzo-feldspathic and biotite-hornblende gneisses with argillic and phyllic alteration. High recoveries of gold-silver ores during mineral processing, are possible due to free occurrence of gold grains, simple intergrowths with ore minerals and absence of harmful minerals.
Key words: Deposit, gold, silver, hydrothermal, ore, mineral processing
El yacimiento La Tosca está ubicado a 1 Km al NW del Municipio de Vetas (Santander-Colombia), geologicamente se localiza en el Macizo de Santander. Corresponde a un depósito hidrotermal de oro y plata, en el cual la dirección preferencial de la mineralización filoniana es N40W. El oro ocurre de forma libre, incluido o asociado a ilmenita, galena. Otros minerales de la mena son pirita, calcopirita, plata, pirrotina, magnetita.La roca encajante de la mineralización es un neis cuarzo-feldespático con biotita variando a neis biotítico-hornbléndico , presentando alteración filica a argilica. La ocurrencia del oro en forma libre o asociado en intercrecimientos simples a óxidos, así como la ausencia de minerales cianicidas determinan un buen comportamiento de la mena durante el procesamiento mineral.
Palabras claves: Yacimiento, oro, plata, hidrotermal, mena, beneficio
 
GEOLOGICAL AND MINERALOGICAL CHARACTERIZATION OF LA TOSCA DEPOSIT (VETAS, SANTANDER, COLOMBIA): IMPLICATIONS FOR MINERAL PROCESSING OF GOLD-SILVER ORES
La Tosca, a gold-silver hydrothermal deposit is located 1 Km Northwest Vetas (Santander, Colombia) and geologically, it is part of the Santander Massif. Gold occurs as free grains, included or associated to ilmenite, galena and in veins with a preferred orientation N40W. Other ore minerals are pyrite, chalcopyrite, silver, pyrrhotite and magnetite. Wall rocks comprises quartzo-feldspathic and biotite-hornblende gneisses with argillic and phyllic alteration. High recoveries of gold-silver ores during mineral processing, are possible due to free occurrence of gold grains, simple intergrowths with ore minerals and absence of harmful minerals.
Key words: Deposit, gold, silver, hydrothermal, ore, mineral processing
El yacimiento La Tosca está ubicado a 1 Km al NW del Municipio de Vetas (Santander-Colombia), geologicamente se localiza en el Macizo de Santander. Corresponde a un depósito hidrotermal de oro y plata, en el cual la dirección preferencial de la mineralización filoniana es N40W. El oro ocurre de forma libre, incluido o asociado a ilmenita, galena. Otros minerales de la mena son pirita, calcopirita, plata, pirrotina, magnetita.La roca encajante de la mineralización es un neis cuarzo-feldespático con biotita variando a neis biotítico-hornbléndico , presentando alteración filica a argilica. La ocurrencia del oro en forma libre o asociado en intercrecimientos simples a óxidos, así como la ausencia de minerales cianicidas determinan un buen comportamiento de la mena durante el procesamiento mineral.
Palabras claves: Yacimiento, oro, plata, hidrotermal, mena, beneficio
 
A Vector Non-abelian Chern-Simons Duality
Abelian Chern-Simons gauge theory is known to possess a `-self-dual'
action where its coupling constant is inverted {\it i.e.} . Here a vector non-abelian duality is found in the
pure non-abelian Chern-Simons action at the classical level. The dimensional
reduction of the dual Chern-Simons action to two-dimensions constitutes a dual
Wess-Zumino-Witten action already given in the literature.Comment: 14+1 pages, LaTeX file, no figures, version to appear in Phys. Rev
On S-duality in (2+1)-Chern-Simons Supergravity
Strong/weak coupling duality in Chern-Simons supergravity is studied. It is
argued that this duality can be regarded as an example of superduality. The use
of supergroup techniques for the description of Chern-Simons supergravity
greatly facilitates the analysis.Comment: 10+1 pages, latex, no figure
Flexible workflows for on-the-fly electronmicroscopy single-particle image processing using Scipion
Electron microscopy of macromolecular structures is an approach that is in increasing demand in the field of structural biology. The automation of image acquisition has greatly increased the potential throughput of electron microscopy. Here, the focus is on the possibilities in Scipion to implement flexible and robust image-processing workflows that allow the electron-microscope operator and the user to monitor the quality of image acquisition, assessing very simple acquisition measures or obtaining a first estimate of the initial volume, or the data resolution and heterogeneity, without any need for programming skills. These workflows can implement intelligent automatic decisions and they can warn the user of possible acquisition failures. These concepts are illustrated by analysis of the well known 2.2 Å resolution β-galactosidase data setThe authors would like to acknowledge financial support from
The Spanish Ministry of Economy and Competitiveness
through the BIO2016-76400-R (AEI/FEDER, UE) grant, the
Comunidad Auto´noma de Madrid through grant S2017/BMD3817, the Instituto de Salud Carlos III (PT17/0009/0010), the
European Union (EU) and Horizon 2020 through the
CORBEL grant (INFRADEV-1-2014-1, Proposal 654248),
the ‘la Caixa’ Foundation (ID 100010434, Fellow LCF/BQ/
IN18/11660021), Elixir–EXCELERATE (INFRADEV-3-
2015, Proposal 676559), iNEXT (INFRAIA-1-2014-2015,
Proposal 653706), EOSCpilot (INFRADEV-04-2016,
Proposal 739563) and INSTRUCT–ULTRA (INFRADEV03-2016-2017, Proposal 731005
Consenso colombiano de atención, diagnóstico y manejo de la infección por SARS-COV-2/COVID-19 en establecimientos de atención de la salud Recomendaciones basadas en consenso de expertos e informadas en la evidencia
The “Asociación Colombiana de Infectología” (ACIN) and the “Instituto de Evaluación de Nuevas Tecnologías de la Salud” (IETS) created a task force to develop recommendations for Covid 19 health care diagnosis, management and treatment informed, and based, on evidence. Theses reccomendations are addressed to the health personnel on the Colombian context of health services. © 2020 Asociacion Colombiana de Infectologia. All rights reserved
Acceptability and feasibility of a virtual community of practice to primary care professionals regarding patient empowerment : A qualitative pilot study
Background: Virtual communities of practice (vCoPs) facilitate online learning via the exchange of experiences and knowledge between interested participants. Compared to other communities, vCoPs need to overcome technological structures and specific barriers. Our objective was to pilot the acceptability and feasibility of a vCoP aimed at improving the attitudes of primary care professionals to the empowerment of patients with chronic conditions. Methods: We used a qualitative approach based on 2 focus groups: one composed of 6 general practitioners and the other of 6 practice nurses. Discussion guidelines on the topics to be investigated were provided to the moderator. Sessions were audio-recorded and transcribed verbatim. Thematic analysis was performed using the ATLAS-ti software. Results: The available operating systems and browsers and the lack of suitable spaces and time were reported as the main difficulties with the vCoP. The vCoP was perceived to be a flexible learning mode that provided up-to-date resources applicable to routine practice and offered a space for the exchange of experiences and approaches. Conclusions: The results from this pilot study show that the vCoP was considered useful for learning how to empower patients. However, while vCoPs have the potential to facilitate learning and as shown create professional awareness regarding patient empowerment, attention needs to be paid to technological and access issues and the time demands on professionals. We collected relevant inputs to improve the features, content and educational methods to be included in further vCoP implementation. Trial registration: ClinicalTrials.gov, NCT02757781. Registered on 25 April 2016
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
Measurement of charm production at central rapidity in proton-proton collisions at TeV
The -differential production cross sections of the prompt (B
feed-down subtracted) charmed mesons D, D, and D in the rapidity
range , and for transverse momentum GeV/, were
measured in proton-proton collisions at TeV with the ALICE
detector at the Large Hadron Collider. The analysis exploited the hadronic
decays DK, DK, DD, and their charge conjugates, and was performed on a
nb event sample collected in 2011 with a
minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space
the -differential production cross sections at TeV
and our previous measurements at TeV. The results were compared
to existing measurements and to perturbative-QCD calculations. The fraction of
cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/307
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