Geotechnical Evaluation of a Ghanaian Black Cotton Soil for use as Clay Liner in Tailings Dam Construction

The purpose of tailings impoundment is to contain tailings produced from mineral processing. Chemicals used in mineral ex-traction processes are usually hazardous to biota and fauna and their presence in tailings may pollute the environment. To pre-vent the flow of such contaminants from tailing dams into the environment, low permeability membranes or seals are used in the basin of the tailings dam as barrier layer. Geomembranes and natural clay liners are typical examples. The use of naturally occurring clay materials provides the most economical liner for tailings dam construction. Lateritic clay and weathered shale have been evaluated for use as liner. Black cotton soils occur in substantial quantities in parts of Ghana but their potential use as a clay liner has not been evaluated. This study presents laboratory evaluation of a typical black cotton soil from the Accra plains of Ghana as potential clay liner for tailings dam construction. Results of the study indicate that the hydraulic conductiv-ity or permeability, plasticity index, fines content and cation exchange capacity of the black cotton soils met the specification of typical clay liner systems. The soil however failed the specific gravity and liquid limit requirements marginally and hence, the soils may be used as clay lining system in tailings dams

Effectiveness of mobile-phone short message service (SMS) reminders for ophthalmology outpatient appointments: Observational study

Abstract Background Non-attendance for hospital outpatient appointments is a significant problem in many countries. It causes suboptimal use of clinical and administrative staff and financial losses, as well as longer waiting times. The use of Short Message Service (SMS) appointment reminders potentially offers a cost-effective and time-efficient strategy to decrease non-attendance and so improve the efficiency of outpatient healthcare delivery. Methods An SMS text message was sent to patients with scheduled appointments between April and September 2006 in a hospital ophthalmology department in London, reminding them of their appointments. This group acted as the intervention group. Controls were patients with scheduled ophthalmology appointments who did not receive an SMS or any alternative reminder. Results During the period of the study, 11.2% (50/447) of patients who received an SMS appointment reminder were non-attenders, compared to 18.1% (1720/9512) who did not receive an SMS reminder. Non-attendance rates were 38% lower in patients who received an SMS reminder than in patients who did not receive a reminder (RR of non-attendance = 0.62; 95% CI = 0.48 – 0.80). Conclusion The use of SMS reminders for ophthalmology outpatient appointments was associated with a reduction of 38% in the likelihood of patients not attending their appointments, compared to no appointment reminder. The use of SMS reminders may also be more cost-effective than traditional appointment reminders and require less labour. These findings should be confirmed with a more rigorous study design before a wider roll-out.</p

A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk

Binary and multiple star systems are a frequent outcome of the star formation process, and as a result, almost half of all sun-like stars have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large scale fragmentation of turbulent gas cores and filaments or smaller scale fragmentation of a massive protostellar disk due to gravitational instability. Observational evidence for turbulent fragmentation on scales of $>$1000~AU has recently emerged. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems. The triple protostar system L1448 IRS3B is an ideal candidate to search for evidence of disk fragmentation. L1448 IRS3B is in an early phase of the star formation process, likely less than 150,000 years in age, and all protostars in the system are separated by $<$200~AU. Here we report observations of dust and molecular gas emission that reveal a disk with spiral structure surrounding the three protostars. Two protostars near the center of the disk are separated by 61 AU, and a tertiary protostar is coincident with a spiral arm in the outer disk at a 183 AU separation. The inferred mass of the central pair of protostellar objects is $\sim$1 M$_{sun}$, while the disk surrounding the three protostars has a total mass of $\sim$0.30 M_{\sun}. The tertiary protostar itself has a minimum mass of $\sim$0.085 M$_{sun}$. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150~AU and 320~AU, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.Comment: Published in Nature on Oct. 27th. 24 pages, 8 figure

Micellar effect on metal-ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with citric acid

Chemical speciation of citric acid complexes of Co(II), Ni(II), Cu(II) and Zn(II) was investigated pH-metrically in 0.0-2.5% anionic, cationic and neutral micellar media. The primary alkalimetric data were pruned with SCPHD program. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. Alkalimetric titrations were carried out in different relative concentrations (M:L:X = 1:2:5, 1:3:5, 1:5:3) of metal (M) to citric acid. The selection of best chemical models was based on statistical parameters and residual analysis. The species detected were MLH, ML2, ML2H and ML2H2. The trend in variation of stability constants with change in mole fraction of the medium is explained onthe basis of electrostatic and non-electrostatic forces. Distributions of the species with pH at different compositions of micellar media are also presented

Prevalence and Antibiotic Susceptibility Pattern of E. coli Isolated from Urinary Tract Infection in Patients with Renal Failure Disease and Renal Transplant Recipients

Purpose: To determine the common uropathogens found in patients with urinary tract infections and to assess their antibiotic susceptibility patterns.Methods: The prevalence and antibiotic susceptibility pattern of E. coli in urinary tract infection inpatients with renal failure disease and renal transplant recipients (group 1) and in outpatients (group 2), admitted in/attending Imam Reza Hospital in Tabriz, Iran, were determined. Isolates were analyzed by standard methods, and antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method.Results: A total of 136 E. coli strains from 81 females and 55 males were examined. The high level of antibiotic susceptibility for group 1 was cefuroxime/ceftazidime (100 %) and nitrofurantoin (81.63 %), respectively; and for group 2, it was ampicillin (95.83 %) and nitrofurantoin (93.75 %), respectively.Conclusion: The most important finding of this study is that a considerable proportion of the studied E. coli isolates are resistant to the antibiotics tested, except nitrofurantoin. This finding is useful for clinicians to determine appropriate empirical antimicrobial treatment in similar cases and would also help health authorities to formulate antibiotic prescription policies.Keywords: Urinary tract infection, Antibiotic susceptibility pattern, Uropathogens, Renal failure, Renal transplant, Escherichia col

Variation in methods, results and reporting in electronic health record-based studies evaluating routine care in gout: A systematic review

Objective: To perform a systematic review examining the variation in methods, results, reporting and risk of bias in electronic health record (EHR)-based studies evaluating management of a common musculoskeletal disease, gout. Methods: Two reviewers systematically searched MEDLINE, Scopus, Web of Science, CINAHL, PubMed, EMBASE and Google Scholar for all EHR-based studies published by February 2019 investigating gout pharmacological treatment. Information was extracted on study design, eligibility criteria, definitions, medication usage, effectiveness and safety data, comprehensiveness of reporting (RECORD), and Cochrane risk of bias (registered PROSPERO CRD42017065195). Results: We screened 5,603 titles/abstracts, 613 full-texts and selected 75 studies including 1.9M gout patients. Gout diagnosis was defined in 26 ways across the studies, most commonly using a single diagnostic code (n = 31, 41.3%). 48.4% did not specify a disease-free period before ‘incident’ diagnosis. Medication use was suboptimal and varied with disease definition while results regarding effectiveness and safety were broadly similar across studies despite variability in inclusion criteria. Comprehensiveness of reporting was variable, ranging from 73% (55/75) appropriately discussing the limitations of EHR data use, to 5% (4/75) reporting on key data cleaning steps. Risk of bias was generally low. Conclusion: The wide variation in case definitions and medication-related analysis among EHR-based studies has implications for reported medication use. This is amplified by variable reporting comprehensiveness and the limited consideration of EHR-relevant biases (e.g. data adequacy) in study assessment tools. We recommend accounting for these biases and performing a sensitivity analysis on case definitions, and suggest changes to assessment tools to foster this

Uso do Propofol associado a Metadona e bloqueio local com LidocaínA em seis exemplares de Potamotrygon sp.

Fish make up the group of vertebrates with the greatest diversity, and their main characteristic is their aquatic habitat, with primary respiration through gills and ectothermy. The Potamotrygonidae family is an example of cartilaginous fish that includes freshwater rays belonging to South America. As they are restricted to fresh life, they have anatomophysiological particularities that differentiate them from other elasmobranchs. Potamotrygon is the most diverse genus, and although they are not aggressive fish, stingrays of this genus have a retro-serrated sting covered by a venom-producing glandular epithelium. Aiming at the safety of many fish that are protected, and of those responsible for management, this work aims to report the anesthetic protocol for iron resection from six stingrays of the genus Potamotrygon. Six specimens of stingray were sent to the Veterinary Hospital of the Federal University of Uberlândia (HVET-UFU), three of the species Potamotrygon falkneri and three Potamotrygon leopoldi for surgical removal of sting. The anesthetic protocol consisted of methadone induction of anesthesia with propofol in the spiracles, and local blockade with lidocaine without vasoconstrictor. Trans-anesthetic monitoring was performed regarding water temperature, respiratory rate, and heart rate of the animals. All animals were recovered under anesthesia within five minutes, and no complications were recorded. Although the anesthesiology of elasmobranch fish is still an uncertain area due to the scarcity of experimental models, the launched protocol presented extraordinary results for promoting relaxation, analgesia and rapid recovery.Pesquisa sem auxílio de agências de fomentoOs peixes compõem o grupo de vertebrados de maior diversidade, e possuem como principal característica o hábitat aquático, com respiração primária através das brânquias, e ectotermia. A família Potamotrygonidae é um exemplo de peixes cartilaginosos que engloba as raias de água doce pertencentes à América do Sul. Por serem restritas à vida dulcícola, possuem particularidades anatomofisiológicas que as diferenciam dos demais elasmobrânquios. Potamotrygon é o gênero mais diverso, e embora não sejam peixes agressivos, as arraias deste gênero possuem um ferrão retro-serrilhado coberto por um epitélio glandular produtor de peçonha. Visando a segurança de demais peixes que compartilham o aquário, e do responsável pelo manejo, este trabalho objetivou relatar o protocolo anestésico para ressecção do ferrão de seis arraias do gênero Potamotrygon. Foram encaminhadas para o Hospital Veterinário da Universidade Federal de Uberlândia (HVET-UFU) seis exemplares de arraia, sendo três da espécie Potamotrygon falkneri e três Potamotrygon leopoldi para remoção cirúrgica de ferrão. O protocolo anestésico foi composto por metadona indução anestésica com propofol nos espiráculos, e bloqueio local com lidocaína sem vasoconstritor. A monitorização trans-anestésica foi realizada quanto à temperatura da água, frequência respiratória, e a frequência cardíaca dos animais. Todos os animais apresentaram recuperação anestésica em até cinco minutos, e não foram registradas intercorrências. Embora a anestesiologia de peixes elasmobrânquios ainda seja uma área incerta devido à escassez de modelos experimentais, o protocolo empregado apresentou resultados satisfatórios para promover relaxamento, analgesia e rápida recuperação

Heterogeneous impacts of mobility restrictions on air quality in the State of Sao Paulo during the COVID-19 pandemic

Air quality in the State of Sao Paulo was evaluated during the first general State plan of mobility restrictions due to the COVID-19 pandemic (24th March to May 31, 2020). Nitrogen dioxide (NO2), ozone (O-3), particulate matter PM10 and PM2.5 and sulphur dioxide (SO2) concentrations were assessed in cities of the Sao Paulo State with a monitoring station and compared to historical data. Linear regression models were built to investigate the relationship between the isolation of the population - determined using mobile phone monitoring data - and the concentration of each pollutant during the studied period. Although the reduction of pollutants such as NO2, SO2 and PM2.5 is very clear, the economic and climatic characteristics of each region were decisive in the general behaviour of O-3 and PM10. It was not possible to establish a correlation between the pollutants and the isolation index, partly due to the lack of data, partly due to the compliance of the population to those measurements, which was variable over time. Another important limitation factor was the absence of data related to the pollutants of interest in many of the stations. However, the isolation measures carried out in the State opened the opportunity to individually assess the air quality measurements in each of the stations, enabling an understanding that will allow in the future the design of air quality policies together with local sanitary policies