650 research outputs found
The Origin Of The Cabacal Cu-au Deposit, Alto Jauru Greenstone Belt, Brazil
The Cabacal Deposit is located in the southern part of the Amazonian Craton (Brazil). It is hosted within the felsic volcanic and volcanoclastic rocks of the Proterozoic Alto Jauru Greenstone Belt.;The processes leading to the deposit are under debate. Some consider the Cabacal Deposit to be of shear-related origin, whereas some interpreted it to be a syngenetic deposit. The present study concludes that the Cabacal Deposit is a deformed volcanogenic massive sulphide deposit. The age of the volcanic system is around 1.7Ga, and of deformation is around 1.6Ga.;Host rocks are commonly sheared parallel to lithological boundaries. Intensive alteration affected the host rocks in the vicinity of the ore bodies. This alteration zone consists of an inner chloritized core, surrounded by a sericitic zone similar to those that occur in VMS deposits. The felsic volcanic host rocks have chemical characteristics pointing to their generation in an island arc environment.;Of the intrusive bodies of the area, the Cabacal Tonalites have some chemical similarities with the felsic volcanic rocks from the Manuel Leme Formation. They also show characteristics of an island arc environment. Possibly, the intrusion took place simultaneously with the shear that affected that area.;Ore in Cabacal is distributed in three zones (South, Central and East Copper Zones) composed of a portion rich in copper and a stringer zone of quartz and sulphide veins. The Central Copper Zone shows a massive sulphide body. Mineralization occurs as landed, veined, breccia and massive ore.;The first mineralizing event in Cabacal is syngenetic with the Manuel Leme formation deposition and it generated a VMS deposit. The second mineralizing event is deformation-related, and redistributed gold into structural features, creating zones with high gold grades. Different fluids were involved in the first mineralization event. Geochemical and thermometric studies suggest fluids with low salinities and of a wide range in temperature (240 to 340{dollar}\sp\circ{dollar}C). Gold transport occurred as Au(HS){dollar}\sp-\sb2{dollar} or AuCl{dollar}\sp-\sb2,{dollar} depending on the associated paragenesis. Results of oxygen isotope studies indicate a fluid with low {dollar}\delta\sp{lcub}18{rcub}{dollar}O ({dollar}-{dollar}2.85 to +2.3), similar to those from the Kuroko mines
To Ada or not To Ada: Adaing vs. Javaing in real-time systems
Ada is really an unfortunate Lady. After years fighting against C/C++ villains, her major lift-up
(Ada 95) had brought up a promise of fortune. However, a new strong villain (Java) has appeared
trying to end her struggle for survival.
Ada has now to fight with her own weapons. She will only prosper by her own merits. But two
questions emerge. Do they exist? Are they better than Java’s? Our opinion is that they do exist,
and are not matched by any other programming languageFLAD; DEMEGI/FEU
The DEAR-COTS hard real-time subsystem
In this report, the Hard Real-Time Subsystem of DEAR-COTS is described, and the services
it must provide are identified. This report is an input of ISEP/IPP and FEUP for the
specification of the DEAR-COTS architecture (deliverable to the FCT)
Flow of low viscosity Boger fluids through a microfluidic hyperbolic contraction
In this work we focus on the development of low viscosity Boger fluids and assess their elasticity analyzing the flow through a microfluidic hyperbolic contraction. Rheological tests in shear and extensional flows were carried out in order to evaluate the effect of the addition of a salt (NaCl) to dilute aqueous solutions of polyacrylamide at 400, 250, 125 and 50 ppm (w/w). The rheological data showed that when 1% (w/w) of NaCl was added, a significant decrease of the shear viscosity curve was observed, and a nearly constant shear viscosity was found for a wide range of shear rates, indicating Boger fluid behavior. The relaxation times, measured using a capillary break-up extensional rheometer (CaBER), decreased for lower polymer concentrations, and with the addition of NaCl. Visualizations of these Boger fluids flowing through a planar microfluidic geometry containing a hyperbolic contraction, which promotes a nearly uniform extension rate at the centerline of the geometry, was important to corroborate their degree of elasticity. Additionally, the quantification of the vortex growth upstream of the hyperbolic contraction was used with good accuracy and reproducibility to assess the relaxation time for the less concentrated Boger fluids, for which CaBER measurements are difficult to perform
Nanogel formation of polymer solutions flowing through porous media
A gelation process was seen to occur when Boger fluids made from aqueous solutions of polyacrylamide (PAA) and NaCl flowed through porous media with certain characteristics. As these viscoelastic fluids flow through a porous medium, the pressure drop across the bed varies linearly with the flow rate, as also happens with Newtonian fluids. Above a critical flow rate, elastic effects set in and the pressure drop grows above the low-flow-rate linear regime. Increasing further the flow rate, a more dramatic increase in the slope of the pressure drop curve can be observed as a consequence of nanogel formation. In this work, we discuss the reasons for this gelation process based on our measurements using porous media of different sizes, porosity and chemical composition. Additionally, the rheological properties of the fluids were investigated for shear and extensional flows. The fluids were also tested as they flowed through different microfluidic analogues of the porous media. The results indicate that the nanogel inception occurs with the adsorption of PAA molecules on the surface of the porous media particles that contain silica on their surfaces. Subsequently, if the interparticle space is small enough a jamming process occurs leading to flow-induced gel formation
Methadone Withdrawal-Related Psychosis in a Patient With Hormone-Dependent Breast Cancer: A Case Report
Methadone withdrawal usually presents as a classical opiate withdrawal syndrome, including symptoms such as restlessness, pupillary dilation, sweating, insomnia, irritability, sneezing, nausea, vomiting, and diarrhea. It rarely manifests as psychosis. Here, we discuss the case of a 43-year-old female with a history of long-term methadone use who presented with first-episode psychosis during methadone down-titration. She exhibited persecutory delusions and auditory hallucinations, unrelated to classical opiate withdrawal symptoms. Medical tests were unremarkable. The patient was diagnosed with first-episode psychosis and was involuntarily admitted to our psychiatric hospital. As she suffered from hormone-dependent breast cancer and presented paliperidone-induced hyperprolactinemia, we switched this drug to aripiprazole, a prolactin-sparing antipsychotic. Her psychotic symptoms remitted in six weeks, with no reintroduction of methadone. It remains unclear whether this presentation is attributable to a rare manifestation of withdrawal or methadone's antipsychotic properties, masking an underlying psychotic disorder. This case contributes to understanding psychosis emergence post-opioid withdrawal, underscoring the need for further investigation into withdrawal-related psychosis and opioid antipsychotic properties. It also prompts the discussion of antipsychotic treatment in patients with comorbid breast cancer, while evidence about hyperprolactinemia as a risk factor for breast cancer remains conflictinginfo:eu-repo/semantics/publishedVersio
SAR calculation using FDTD simulations
The main intend of this work, is to determinate the Specific Absorption Rate (SAR) on human head tissues exposed to radiation caused by sources of 900 and 1800MHz, since those are the typical frequencies for mobile communications systems nowadays. In order to determinate the SAR, has been used the FDTD (Finite Difference Time Domain), which is a numeric method in time domain, obtained from the Maxwell equations in differential mode. In order to do this, a computational model from the human head in two dimensions made with cells of the smallest possible size was implemented, respecting the limits from computational processing. It was possible to verify the very good efficiency of the FDTD method in the resolution of those types of problems
Modulation of ankle antagonist co-activation during the transition from upright standing to gait and to sit in post-stroke subjects
Antagonist co-activation represents a neuronal command for the modulation of muscle synergies with postural control purposes, probably assuming a key role in the characterisation of tonus dysfunction in post-stroke subjects. This study aims to evaluate the ankle antagonist co-activation during different functional tasks in post-stroke subjects. The CONTRA limb presented decreased values in TA/SOL pair during upright standing and increased values in both muscle pairs during gait initiation compared to the IPSI limb (Table 1). No significant differences were found between tasks (Table 1). he IPSI and CONTRA limbs presented increased antagonist co-activation when an adequate antigravity function and the coordination of the tibia forward rotation are required, respectively. The comparison of these values with that obtained by healthy subjects seems to point to a bilateral postural control dysfunction in post-stroke subjects related to tonus modulation deficits that should be addressed in neurorehabilitation. Future studies with a higher sample are required to extend the results.info:eu-repo/semantics/publishedVersio
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