1,672 research outputs found

    Advanced load-shift system: an experimental validation of the ac-dc converter as shunt active power filter

    Get PDF
    This paper presents a load-shift system with advanced functionalities to interface the power grid (PG). When compared with the conventional approach, an advanced load-shift system (aLSS) permits the compensation of power quality (PQ) problems for the grid-side, namely problems related to current harmonics, current imbalance, and power factor. The proposed aLSS is composed by a bidirectional ac-dc converter to interface the PG and by a bidirectional dc-dc converter to interface an energy storage system (ESS). Since the main innovation is related with the PG interface, the focus of this work is on the analysis of the ac-dc converter, which is based on a three-phase four-leg converter. A theoretical study and the details concerning the control algorithm are presented and discussed along the paper. A laboratory prototype of the proposed aLSS was developed and the details of implementation are described in the paper. Experimental results obtained with the developed prototype prove that the aLSS contributes for the technology progress in this area, validating a new concept of operation concerning the PQ on the PG side.This work has been supported by FCT – Fundação para a Ciência e Tecnologia with-in the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project QUALITY4POWER PTDC/EEI-EEE/28813/2017, and by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017

    Black Stork Down: Military Discourses in Bird Conservation in Malta

    Get PDF
    Tensions between Maltese hunters and bird conservation NGOs have intensified over the past decade. Conservation NGOs have become frustrated with the Maltese State for conceding to the hunter lobby and negotiating derogations from the European Union’s Bird Directive. Some NGOs have recently started to organize complex field-operations where volunteers are trained to patrol the landscape, operate drones and other surveillance technologies, detect illegalities, and lead police teams to arrest poachers. We describe the sophisticated military metaphors which conservation NGOs have developed to describe, guide and legitimize their efforts to the Maltese public and their fee-paying members. We also discuss why such groups might be inclined to adopt these metaphors. Finally, we suggest that anthropological studies of discourse could help understand delicate contexts such as this where conservation NGOs, hunting associations and the State have ended in political deadlock

    Trace-gas metabolic versatility of the facultative methanotroph Methylocella silvestris

    Get PDF
    The climate-active gas methane is generated both by biological processes and by thermogenic decomposition of fossil organic material, which forms methane and short-chain alkanes, principally ethane, propane and butane1, 2. In addition to natural sources, environments are exposed to anthropogenic inputs of all these gases from oil and gas extraction and distribution. The gases provide carbon and/or energy for a diverse range of microorganisms that can metabolize them in both anoxic3 and oxic zones. Aerobic methanotrophs, which can assimilate methane, have been considered to be entirely distinct from utilizers of short-chain alkanes, and studies of environments exposed to mixtures of methane and multi-carbon alkanes have assumed that disparate groups of microorganisms are responsible for the metabolism of these gases. Here we describe the mechanism by which a single bacterial strain, Methylocella silvestris, can use methane or propane as a carbon and energy source, documenting a methanotroph that can utilize a short-chain alkane as an alternative to methane. Furthermore, during growth on a mixture of these gases, efficient consumption of both gases occurred at the same time. Two soluble di-iron centre monooxygenase (SDIMO) gene clusters were identified and were found to be differentially expressed during bacterial growth on these gases, although both were required for efficient propane utilization. This report of a methanotroph expressing an additional SDIMO that seems to be uniquely involved in short-chain alkane metabolism suggests that such metabolic flexibility may be important in many environments where methane and short-chain alkanes co-occur

    Necrotising fasciitis of the shoulder in association with rheumatoid arthritis treated with etanercept: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Necrotising fasciitis is a severe infection characterised by the fulminant destruction of tissue with associated systemic signs of sepsis and toxicity. Etanercept is a fully human fusion protein that inhibits tumor necrosis factor and the inflammatory cascade. It is effective in the treatment of many disorders but concerns regarding severe life threatening infections have been raised in multiple reports.</p> <p>Case presentation</p> <p>We present the case of a 39-year-old Caucasian man, who presented with sudden onset of severe and progressive neck and left shoulder pain, with a two-year history of seronegative rheumatoid arthritis treated with azathoprine and etanercept. On examination the left side of his neck and his left shoulder were oedematous, tender with an erythematous rash and his active range of movement was limited. Magnetic resonance imaging of his shoulder showed extensive oedema of the subcutaneous and intramuscular fat of the left lower neck consistent with fasciitis. He was treated medically and made a good recovery.</p> <p>Conclusion</p> <p>Our patient, while having a pre-existing increased mortality risk, had a serious infection which responded well to optimum medical treatment without the need for surgery. As anti tumor necrosis factor agents are frequently associated with infection, including tuberculous infection, this case highlights the need for a high index of suspicion for other severe bacterial infections in patients on immunosuppressants.</p

    Hospitalization for Heart Failure in the United States, UK, Taiwan, and Japan: An International Comparison of Administrative Health Records on 413,385 Individual Patients

    Get PDF
    BACKGROUND: Registries show international variations in the characteristics and outcome of patients with heart failure (HF) but national samples are rarely large, and case-selection may be biased due to enrolment in academic centres. National administrative datasets provide large samples with a low risk of bias. In this study, we compared the characteristics, healthcare resource utilization (HRU) and outcomes of patients with primary HF hospitalizations (HFH) using electronic health records (EHR) from four high-income countries (USA, UK, Taiwan, Japan) on three continents. METHODS AND RESULTS: We used EHR to identify unplanned HFH between 2012-2014. We identified 231,512, 10,991, 36,900 and 133,982 patients with a primary HFH from USA, UK, Taiwan and Japan, respectively. HFH per 100,000 population was highest in USA and lowest in Taiwan. Patients in Taiwan and Japan were older but fewer were obese or had chronic kidney disease. LOHS was shortest in USA (median 4 days) and longer in UK, Taiwan and Japan (medians 7, 9 and 17 days, respectively). HRU during hospitalization was highest in Japan and lowest in UK. Crude and direct standardized in-hospital mortality was lowest in USA (direct standardized rates: 1.8 [95%CI:1.7-1.9]%)and progressively higher in Taiwan (direct standardized rates: 3.9 [95%CI:3.8-4.1]%), UK (direct standardized rates: 6.4 [95%CI:6.1-6.7]%) and Japan (direct standardized rates: 6.7 [95%CI:6.6-6.8]%). 30-day all-cause (25.8%) and HF (7.2%) readmissions were highest in USA and lowest in Japan (11.9% and 5.1% respectively). CONCLUSION: Marked international variations in patient characteristics, HRU and clinical outcome exist; understanding them might inform health care policy and international trial design

    Circulating microRNAs Reveal Time Course of Organ Injury in a Porcine Model of Acetaminophen-Induced Acute Liver Failure

    Get PDF
    Acute liver failure is a rare but catastrophic condition which can progress rapidly to multi-organ failure. Studies investigating the onset of individual organ injury such as the liver, kidneys and brain during the evolution of acute liver failure, are lacking. MicroRNAs are short, non-coding strands of RNA that are released into the circulation following tissue injury. In this study, we have characterised the release of both global microRNA and specific microRNA species into the plasma using a porcine model of acetaminophen-induced acute liver failure. Pigs were induced to acute liver failure with oral acetaminophen over 19h±2h and death occurred 13h±3h thereafter. Global microRNA concentrations increased 4h prior to acute liver failure in plasma (P<0.0001) but not in isolated exosomes, and were associated with increasing plasma levels of the damage-associated molecular pattern molecule, genomic DNA (P<0.0001). MiR122 increased around the time of onset of acute liver failure (P<0.0001) and was associated with increasing international normalised ratio (P<0.0001). MiR192 increased 8h after acute liver failure (P<0.0001) and was associated with increasing creatinine (P<0.0001). The increase in miR124-1 occurred concurrent with the pre-terminal increase in intracranial pressure (P<0.0001) and was associated with decreasing cerebral perfusion pressure (P<0.002)

    Epidemiology of Coxiella burnetii infection in Africa: a OneHealth systematic review

    Get PDF
    Background: Q fever is a common cause of febrile illness and community-acquired pneumonia in resource-limited settings. Coxiella burnetii, the causative pathogen, is transmitted among varied host species, but the epidemiology of the organism in Africa is poorly understood. We conducted a systematic review of C. burnetii epidemiology in Africa from a “One Health” perspective to synthesize the published data and identify knowledge gaps.&lt;p&gt;&lt;/p&gt; Methods/Principal Findings: We searched nine databases to identify articles relevant to four key aspects of C. burnetii epidemiology in human and animal populations in Africa: infection prevalence; disease incidence; transmission risk factors; and infection control efforts. We identified 929 unique articles, 100 of which remained after full-text review. Of these, 41 articles describing 51 studies qualified for data extraction. Animal seroprevalence studies revealed infection by C. burnetii (&#8804;13%) among cattle except for studies in Western and Middle Africa (18–55%). Small ruminant seroprevalence ranged from 11–33%. Human seroprevalence was &#60;8% with the exception of studies among children and in Egypt (10–32%). Close contact with camels and rural residence were associated with increased seropositivity among humans. C. burnetii infection has been associated with livestock abortion. In human cohort studies, Q fever accounted for 2–9% of febrile illness hospitalizations and 1–3% of infective endocarditis cases. We found no studies of disease incidence estimates or disease control efforts.&lt;p&gt;&lt;/p&gt; Conclusions/Significance: C. burnetii infection is detected in humans and in a wide range of animal species across Africa, but seroprevalence varies widely by species and location. Risk factors underlying this variability are poorly understood as is the role of C. burnetii in livestock abortion. Q fever consistently accounts for a notable proportion of undifferentiated human febrile illness and infective endocarditis in cohort studies, but incidence estimates are lacking. C. burnetii presents a real yet underappreciated threat to human and animal health throughout Africa.&lt;p&gt;&lt;/p&gt

    Management of Hepatitis C Antiviral Therapy Adverse Effects

    Get PDF
    Hepatitis C is one of the leading causes of liver disease in the United States, affecting more than 4 million individuals. The current treatment regimen involves pegylated interferon in combination with ribavirin. Although antiviral treatment has been associated with a greater than 50% sustained viral response rate, the adverse effects have proven to be detrimental to quality of life and therapy adherence, and consequently lead to lower sustained viral response rates. This article identifies the most frequently described complications associated with pegylated interferon and ribavirin. The active management of these complications is discussed, including both preventive and empiric treatments
    corecore