DC Voltage Droop Control Implementation in the AC/DC Power Flow Algorithm: Combinational Approach

In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include the DC voltage droop control. In the VSC based MTDC grids, the DC droop control is regarded as more advantageous in terms of the operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently

Hierarchical Control Implementation for Meshed AC/Multi-terminal DC Grids with Offshore Windfarms Integration

Although the integration of meshed multi-terminal direct current (MTDC) grids with the existing AC grid has some added economic advantages, significant challenges are encountered in such systems. One of the major challenges is ensuring secure and optimal operation of the combined AC/MTDC grid considering the stability requirements of AC and DC grids at different operating conditions. This paper presents the implementation of hierarchical control for the combined AC/MTDC grid. The hierarchical control is based on the well-established three-layered control of the AC power system, comprising primary, secondary, and tertiary controls. A set of appropriate control methods are proposed for the primary, secondary, and tertiary control layers to accomplish the identified requirements for secure and optimal operation of the combined AC/MTDC grid

Tuberculosis diagnosis cascade in Blantyre, Malawi : a prospective cohort study

Wellcome Trust. PM is funded by Wellcome (206575/Z/17/Z). ELC is funded by Wellcome (200901/Z/16/Z). ELW received salary funding from the UK Medical Research Council (grant number MR/K012126/1), this award is jointly funded by the UK Medical Research Council (MRC) and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement and is also part of the EDCTP2 programme supported by the European Union.Background Tuberculosis (TB) control relies on early diagnosis and treatment. International guidelines recommend systematic TB screening at health facilities, but implementation is challenging. We investigated completion of recommended TB screening steps in Blantyre, Malawi. Methods A prospective cohort recruited adult outpatients attending Bangwe primary clinic. Entry interviews were linked to exit interviews. The proportion of participants progressing through each step of the diagnostic pathway were estimated. Factors associated with request for sputum were investigated using multivariable logistic regression. Results Of 5442 clinic attendances 2397 (44%) had exit interviews. In clinically indicated participants (n = 445) 256 (57.5%) were asked about cough, 36 (8.1%) were asked for sputum, 21 (4.7%) gave sputum and 1 (0.2%) received same-day results. Significant associations with request for sputum were: any TB symptom (aOR:3.20, 95%CI:2.02–5.06), increasing age (aOR:1.02, 95%CI:1.01–1.04 per year) and for HIV-negative participants only, a history of previous TB (aOR:3.37, 95%CI:1.45–7.81). Numbers requiring sputum tests (26/day) outnumbered diagnostic capacity (8–12/day). Conclusions Patients were lost at every stage of the TB care cascade, with same day sputum submission following all steps of the diagnosis cascade achieved in only 4.7% if clinically indicated. Infection control strategies should be implemented, with reporting on early steps of the TB care cascade formalised. High-throughput screening interventions, such as digital CXR, that can achieve same-day TB diagnosis are urgently needed to meet WHO End TB goals.Peer reviewe

Tuberculosis diagnosis cascade in Blantyre, Malawi: a prospective cohort study.

BACKGROUND: Tuberculosis (TB) control relies on early diagnosis and treatment. International guidelines recommend systematic TB screening at health facilities, but implementation is challenging. We investigated completion of recommended TB screening steps in Blantyre, Malawi. METHODS: A prospective cohort recruited adult outpatients attending Bangwe primary clinic. Entry interviews were linked to exit interviews. The proportion of participants progressing through each step of the diagnostic pathway were estimated. Factors associated with request for sputum were investigated using multivariable logistic regression. RESULTS: Of 5442 clinic attendances 2397 (44%) had exit interviews. In clinically indicated participants (n = 445) 256 (57.5%) were asked about cough, 36 (8.1%) were asked for sputum, 21 (4.7%) gave sputum and 1 (0.2%) received same-day results. Significant associations with request for sputum were: any TB symptom (aOR:3.20, 95%CI:2.02-5.06), increasing age (aOR:1.02, 95%CI:1.01-1.04 per year) and for HIV-negative participants only, a history of previous TB (aOR:3.37, 95%CI:1.45-7.81). Numbers requiring sputum tests (26/day) outnumbered diagnostic capacity (8-12/day). CONCLUSIONS: Patients were lost at every stage of the TB care cascade, with same day sputum submission following all steps of the diagnosis cascade achieved in only 4.7% if clinically indicated. Infection control strategies should be implemented, with reporting on early steps of the TB care cascade formalised. High-throughput screening interventions, such as digital CXR, that can achieve same-day TB diagnosis are urgently needed to meet WHO End TB goals

Tandem E2F Binding Sites in the Promoter of the p107 Cell Cycle Regulator Control p107 Expression and Its Cellular Functions

The retinoblastoma tumor suppressor (Rb) is a potent and ubiquitously expressed cell cycle regulator, but patients with a germline Rb mutation develop a very specific tumor spectrum. This surprising observation raises the possibility that mechanisms that compensate for loss of Rb function are present or activated in many cell types. In particular, p107, a protein related to Rb, has been shown to functionally overlap for loss of Rb in several cellular contexts. To investigate the mechanisms underlying this functional redundancy between Rb and p107 in vivo, we used gene targeting in embryonic stem cells to engineer point mutations in two consensus E2F binding sites in the endogenous p107 promoter. Analysis of normal and mutant cells by gene expression and chromatin immunoprecipitation assays showed that members of the Rb and E2F families directly bound these two sites. Furthermore, we found that these two E2F sites controlled both the repression of p107 in quiescent cells and also its activation in cycling cells, as well as in Rb mutant cells. Cell cycle assays further indicated that activation of p107 transcription during S phase through the two E2F binding sites was critical for controlled cell cycle progression, uncovering a specific role for p107 to slow proliferation in mammalian cells. Direct transcriptional repression of p107 by Rb and E2F family members provides a molecular mechanism for a critical negative feedback loop during cell cycle progression and tumorigenesis. These experiments also suggest novel therapeutic strategies to increase the p107 levels in tumor cells

Selected facets of the fishing industry (early 1963)

Consumer demand, retail distribution and the export trade are important aspects of the New Zealand Commercial Fishery which are outside the specific boundaries of this enquiry. It is a study in government intervention, price negotiation and supply. In analysing these three facets of the industry it was impossible to ignore the other three so they have been treated incidentally where a discussion of them was necessary to understand the central theme. There is scope for additional research into each of the above topics, perhaps more especially into administrative decision making when non economic objectives are involved and also into the optimum scale of plant given the cost conditions that apply to the industry. However, it is hoped that this essay goes part of the way towards meeting the need for fundamental economic research into an industry which periodically attracts the attention of the public, policy makers and Government. Parliament has set up three committees in the past twenty-six years to examine the industry