Three-dimensional geometry, ore distribution and time-integrated mass transfer through the quartz-tourmaline-gold vein network of the Sigma deposit (Abitibi belt, Canada)

We present a reconstruction of the three-dimensional (3D) geometry and gold grade distribution of shear zone-hosted, Au-mineralized, quartz-tourmaline veins of the Sigma deposit (Abitibi belt). Host shears and veins form a network of anastomosing, steeply dipping structures associated with smaller subhorizontal extensional veins. Our reconstruction has been carried out using the exceptionally large geological database of the mine. From this database, we extracted the geometric position, thickness and gold grades of geometrically best-defined steep veins contained in a representative subvolume of the deposit. These data allowed the 3D representation of 53 veins, which have been constructed by fitting surfaces through the geometrical data and by contouring thickness and gold grade. The geometry of the network is mainly characterized by: (i) a few large segmented veins, with sinuous and helicoidal shape, and typical vertical dimension of >100 m; (ii) a large number of smaller vertical veins, some of which splay off the steep veins with high dip angles; (iii) subhorizontal extension veins (joints) located at, or close to, the tips of steep veins. The absolute thickness of the vertically short veins is the same as that of the large veins, suggesting that they formed simultaneously, but only a few of them interconnect to form vertically continuous bodies. Patchy, vertically elongated zones of high dilation are present in the large veins, and are poorly correlated with Au-rich zones. They presumably represent former high-permeability zones of the network. The highest gold grades occur at the interconnections between the large veins and small splays or subhorizontal joints. This indicates the important role of vein interconnection for fluid flow and gold precipitation within the network. Combining the calculation of the volume of the network with the estimation of tourmaline abundance in the veins, we calculate that 2.1 × 106 m3 of tourmaline and 3.2 × 106 m3 of quartz precipitated during Au deposition

The separate collection of recyclable waste materials as a fywheel for the circular economy: the role of institutional quality and socio‑economic factors

The separate collection of individual recyclable waste materials is the basis for any recycling process. This produces important advantages, especially in terms of resource savings. This paper investigates the drivers of the separate collection process of recyclable materials (i.e., organic, paper, glass, plastic) and its total in the 103 Italian provinces (NUTS-3), in the years 2004–2011. Results show that the pillars of institutional quality (such as, voice and accountability, rule of law and regulatory quality), value added per capita and participation to ecological associations are important factors for an effective implementation of the waste separation process. In particular, these factors do matter for an effective collection of organic waste, paper, glass and plastic. Furthermore, the analysis shows marked differences among macro-areas (North, Central and Southern Italy). Policy considerations are discussed

EFFECTS OF RECLAIMED ASPHALT, WAX ADDITIVE, AND COMPACTION TEMPERATURE ON CHARACTERISTICS AND MECHANICAL PROPERTIES OF POROUS ASPHALT

This paper describes physical and mechanical properties of porous asphalt mixtures with various RAP amount (0%, 10%, 20%, 30%) containing one WMA additive (organic wax). The samples were prepared using the Marshall compactor at two different temperatures (125 °C, 145 °C) by fabricating six series of porous mixtures. Air void content, particle loss, stiffness modulus, indirect tensile strength, and indirect tensile strength ratio were measured and the effects of RAP, wax, and compaction temperatures were evaluated, considering the results of statistical analyses. Based on the performed tests, it has been concluded that high RAP contents (30%) in WMA-RAP PAs result in decreased porosity, permeability, and moisture resistance, and in increased cohesiveness, stiffness, and indirect tensile strength compared to the reference PAs. On the other hand, for low RAP contents (10%), WMA-RAP PAs show lower cohesiveness and indirect tensile strength, at the same time demonstrating an increase in porosity, permeability, moisture resistance, and stiffness. Reduced compaction temperatures (125 °C) particularly affect the cracking resistance

Surgical management of complex ileocolonic Crohn’s disease: a survey of IBD colorectal surgeons to assess variability in operative strategy

Cirurgia colorectal; Malaltia de Crohn; Resecció ileocecalCirugía colorrectal; Enfermedad de Crohn; Resección ileocecalColorectal surgery; Crohn’s disease; Ileocaecal resectionIntroduction To explore the reported variability in the surgical management of ileocolonic Crohn’ s disease and identify areas of standard practice, we present this study which aims to assess how different colorectal surgeons with a subspecialty interest in inflammatory bowel disease (IBD) surgery may act in different clinical scenarios of ileocolonic Crohn’s disease. Methods Anonymous videos demonstrating the small bowel walkthrough and anonymised patients’ clinical data, imaging and pathological findings were distributed to the surgeons using an electronic tool. Surgeons answered on operative strategy, bowel resections, management of small bowel mesentery, type of anastomosis and use of stomas. Results Eight small bowel walkthrough videos were registered and 12 assessors completed the survey with a questionnaire completion rate of 87.5%. There was 87.7% agreement in the need to perform an ileocolonic resection. However, the agreement for the need to perform associated surgical procedures such as strictureplasties or further bowel resections was only 57.4%. When an anastomosis was fashioned, the side to side configuration was the most commonly used. The preferred management of the mesentery was dissection close to the bowel. Conclusions The decision on the main procedure to be performed had a high agreement amongst the different assessors, but the treatment of multifocal disease was highly controversial, with low agreement on the need for associated procedures to treat internal fistulae and the use of strictureplasties. At the same time, there was significant heterogeneity in the decision on when to anastomose and when to fashion an ileostomy

Mental health professionals’ knowledge, skills and attitudes on domestic violence and abuse in the Netherlands:Cross-sectional study

Background Despite the high prevalence of domestic violence and abuse (DVA) among patients with psychiatric conditions, detection rates are low. Limited knowledge and skills on DVA in mental healthcare (MHC) professionals might contribute to poor identification.AimsTo assess the level of, and factors associated with, DVA knowledge and skills among MHC professionals. Method A total of 278 professionals in Dutch MHC institutions completed a survey assessing factual knowledge, perceived knowledge, perceived skills and attitudes about DVA. Results On average, low scores were reported for perceived skills and knowledge. MHC professionals in primary care scored higher than those working with individuals with severe mental illness (P<0.005). Levels of factual knowledge were higher; levels of attitudes moderate. Previous training was positively associated with skills (odds ratios (OR) = 3.0) and attitudes (OR = 2.7). Years of work was negatively associated with factual knowledge (OR = 0.97). Larger case-loads predicted higher scores on skills (OR = 2.1). Conclusions Training is needed, particularly for clinicians working with patients with severe mental illness

Confirmation of a New Metal-poor Globular Cluster in the Galactic Bulge

© 2018. The American Astronomical Society. All rights reserved.We use deep near-IR photometry of the VISTA Variables in the V'a L'ctea (VVV) Survey and deep DECam Plane Survey (DECaPS) optical photometry to confirm the physical reality of the candidate globular cluster (GC) Minni 22, which is located in the Galactic bulge. This object, which was detected as a high density region in our maps of bulge red giants, is now confirmed as a real GC based on the optical and near-IR color'magnitude diagrams. We also recover three known fundamental mode (ab type) RR Lyrae stars within 2 arcmin of the cluster center. The presence of RR Lyrae stars also seems to confirm Minni 22 as a bonafide old and metal-poor GC. We estimate a cluster reddening E(J - Ks) = 0.6 mag and determine its heliocentric distance D = 7.4 ± 0.3 kpc. The optical and near-IR color'magnitude diagrams reveal well-defined red giant branches in all cases, including a red giant branch bump at Ks = 13.30 ± 0.05 mag. The comparison with theoretical isochrones yields a mean metallicity of [Fe/H] = -1.3 ± 0.3 dex, and age of t ∼ 11.2 Gyr. This is a good example of a new low-luminosity (MV = -6.2 mag) GC found in the central bulge of the Milky Way. After discussing the different ways to confirm the existence of bulge GC candidates, we find that one of the best methods is to use the CMDs from the combination of the DECaPS + VVV photometries.Peer reviewe

Fluid-rock interaction, skarn genesis, and hydrothermal alteration within an upper crustal fault zone (Island of Elba, Italy)

The Terranera magnetite-hematite-pyrite deposit of the Island of Elba (Italy) is an historical skarn deposit hosted by a fault zone of regional importance (Zuccale Fault) and by its hanging wall rocks. We combine field observations with petrographic data, electron probe microanalyses (EPMA), XRPD data, fluid inclusion microthermometry, and element imaging by Laser Ablation-Inductively Coupled Plasma-Time of Flight Mass Spectrometry (LA-ICP-TOFMS) to define the ore-forming process at Terranera. We show that in this location the fault is made of four levels of mineralized fault rocks having distinct mineral compositions. In these levels, a mineral association made of diopside, clinozoisite, and other Mg-rich minerals is replaced by magnetite, hematite, pyrite, Mg-hornblende, clinochlore, and other Mg-rich phyllosilicates. This paragenesis is overprinted by goethite and clay minerals. Chlorite-quartz geothermometry and fluid inclusion microthermometry show that ore precipitation occurred at 350–180 °C from fluids of distinct bulk salinities, but goethite and clay mineral overprinting progressed at lower T. We propose that Terranera is a magnesian Fe skarn formed due to the interaction between distinct hydrothermal fluids and a dolomitic protolith, which was preserved within the fault zone. These fluids mixed and cooled during protolith metasomatism, causing ore precipitation due to oxidation and desulfidation. A very similar process was described in a large deposit of Elba (Rio Marina). Argillic alteration was widespread within the fault but met permanently intermediate sulfidation conditions. Trace element composition of hematite shows that Terranera has features that overlap those of skarn and epithermal deposits. In particular, elements that are typical of epithermal deposits (Sb, Ga, Ge, As) occur at mass fractions (50–200 μg/g) that are either unreported or not typical of hematite from skarn deposits. These features identify Terranera as formed in an ore environment that was transitional between that of a skarn and of an epithermal deposit. These features are shared by other historical deposits located at Elba and in the massive pyritic ore district of south Tuscany (e.g., Gavorrano, Fenice Capanne). This indicates that a similar environment might have occurred during the Neogene beyond Elba, in a much larger ore district of south Tuscany

On the efficiency of the Blandford-Znajek mechanism for low angular momentum relativistic accretion

Blandford-Znajek (BZ) mechanism has usually been studied in the literature for accretion with considerably high angular momentum leading either to the formation of a cold Keplerian disc, or a hot and geometrically thick sub-Keplerian flow as described within the framework of ADAF/RIAF. However, in nearby elliptical galaxies, as well as for our own Galactic centre, accretion with very low angular momentum is prevalent. Such quasi-spherical strongly sub-Keplerian accretion has complex dynamical features and can accommodate stationary shocks. In this letter, we present our calculation for the maximum efficiency obtainable through the BZ mechanism for complete general relativistic weakly rotating axisymmetric flow in the Kerr metric. Both shocked and shock free flow has been studied in detail for rotating and counter rotating accretion. Such study has never been done in the literature before. We find that the energy extraction efficiency is low, about 0.1%, and increases by a factor 15 if the ram pressure is included. Such an efficiency is still much higher than the radiative efficiency of such optically thin flows. For BZ mechanism, shocked flow produces higher efficiency than the shock free solutions and retrograde flow provides a slightly larger value of the efficiency than that for the prograde flow.Comment: Substantially revised final version to appear in MNRAS Letters. Three colour figure