Estimating the Load Response to Voltage Changes at UK Primary Substations

The development of Smart Grid technologies and the need to defer investments for expanding and reinforcing distribution networks have attracted new attention to aspects of Conservation Voltage Reduction (CVR). Based on the fact that the demand of certain loads can change with voltage, it is plausible to envisage the active management of voltage regulation devices in order to increase/decrease the demand during certain periods for the benefit of the distribution network (e.g., peak shaving) or the whole system (e.g., fast reserves). The extent of this voltage-driven demand response is however entirely dependent on the instantaneous load composition. In order to quantify the benefits of such a scheme, this work proposes a methodology to estimate the time-varying residential load response to primary substation voltage changes whilst complying with voltage limits at low voltage. This is applied to a small UK distribution network downstream an OLTC-enabled 33kV/6.6kV substation with 351 residential, 2 commercial and 1 industrial customers (total peak demand of 932 kW). The results, only considering part of the residential loads modeled with time-varying ZIP parameters, suggest that – even considering voltage constraints– there is considerable load response that can be unlocked from residential loads. However, this is highly dependent on the time of the day

Post-occupancy evaluation of the actual performance of a low-carbon building

It is vital that the development of low carbon buildings to achieve carbon neutrality in China. Nonetheless, the actual post-commissioning performance of buildings has gained little attention. A post-occupancy evaluation of low-carbon buildings was conducted, covering analysis of indoor environmental indicators and carbon reduction. The main objective of the study was to assess the post-occupancy performance of low-carbon buildings and to guide their development towards achieving the zero-carbon goal. Specifically, indoor environmental operating parameters and carbon reduction were quantified. The outcomes demonstrated that indoor environmental parameters were influenced by factors, such as room location, room orientation, the behavior of office workers, and the number of office workers. Nevertheless, in terms of long-term trends, the indoor temperature and relative humidity indicators were better than the requirements of the relevant standards. Meanwhile, there is an excellent comfort level in low-carbon buildings, thermal sensations almost constantly behave as neutral. The average CO2 concentration in all rooms was always less than 756 ppm throughout the year, which was 24.4% lower than the standard value. Additionally, the electricity consumption of the actual operation phase of the low-carbon office building was 28.76 kWh/(m2⋅a), the electricity saving rate was 41.28% compared to the electricity consumption of the reference building. The emission reduction of CO2, SO2 and dust were 4.66 kg/m2, 0.04 kg/m2, and 0.02 kg/m2, respectively. Overall, this paper can provide valuable information for the development of zero-carbon buildings

Genetic diversity of Leptospira interrogans circulating isolates and vaccine strains in China from 1954–2014

Leptospirosis is one of the most important but neglected, infectious tropical diseases worldwide. Leptospira interrogans is now recognized as a leading cause of the disease. Little is known of the genetic diversity and phylogenetic characteristics of L. interrogans within China. To better understand the transmission and genetic diversity of L. interrogans populations, we characterized 271 isolates and seven vaccine strains from China during 1954–2014 using multilocus variable-number tandem repeat analysis (MLVA). 110 different L. interrogans MLVA profiles (MTs) were identified, of which five were predominant, reflecting a high level of genetic diversity in L. interrogans population in China. Different from that of circulating isolates, seven vaccine strains have different MT, of which some are phylogenetically away from the circulating isolates. The results showed that Icterohaemorrhagiae, Hebdomadis, and Canicola ranked as the top three serogroups among L. interrogans strains tested. The cluster analysis demonstrate the clonal links between rodent and human isolates, suggesting the rodent species played a key role in the transmission of leptospirosis to humans, and contributed to the circulation of the pathogen in humans. Taken together, these findings should provide insight into a better knowledge of the epidemiology and molecular evolution of L. interrogans in China. Furthermore, the results should facilitate the selection of candidate vaccine strains in the future

Source tracking of human leptospirosis: serotyping and genotyping of Leptospira isolated from rodents in the epidemic area of Guizhou province, China

BACKGROUND: Sustained human leptospirosis as well as death cases has been reported in Qiandongnan Prefecture, Southeast of Guizhou, China, recently, but these human patients were only clinically diagnosed, and leptospires have never been isolated from patients in these epidemic regions, In order to track the source of infection and understand the etiologic characteristic of leptospirosis, we performed rodent carrier surveillance for leptospirosis in the epidemic area in 2011. The population distribution of rodents in the epidemic regions was revealed. RESULTS: Four strains of leptospire were isolated from Apodemus agrarius. Microscopic agglutination test (MAT) confirmed the four isolates belonged to leptospiral serogroup Icterohaemorrhagiae. Multilocus sequence typing (MLST) indicated that all the four strains were defined as sequence type 1(ST1), which is identical to the three strains isolated from Rattus tanezumi in Rongjiang County in 2007. Clustering analysis of the MLST data indicated that the local isolates exactly matched with reference strain of leptospiral serovar Lai strain 56601, which is consistent with anti-Leptospira antibody detection of patients using MAT. CONCLUSIONS: Apodemus agrarius may be the potentially important carrier of leptospirosis and the potential source of leptospiral infection in human, and serovar Lai maybe the epidemic serovar of Leptospira in the localities

The purifying trend in the chromosomal integron in Vibrio cholerae strains during the seventh pandemic

Chromosomal integron (CI) arrays in Vibrio spp. are generally large and display great variation. Here we determined the sequence of CI array in a toxigenic O139 Vibriocholerae strain and compared it with the arrays from the genome of different O1 biotypes available in GenBank. Then PCR scanning was used to determine the CI array variations in 83 epidemic O139 strains and subsequently these variations were compared with that found in toxigenic O1 El Tor strains in our previous work. Few differences were observed in the cohort of toxigenic O139 strains compared to the toxigenic O1 El Tor strains. On the basis of CI arrays, the toxigenic O1 El Tor and O139 strains isolated concurrently in recent years appear to be more similar to each other than to the O1 strains isolated in previous decades, suggesting a closer evolutionary relationship between them. Comparison of CI arrays in toxigenic O1 El Tor and O139 V. cholerae strains isolated between 1961 and 2009 revealed a purifying trend in the CI arrays in the chronological order during the seventh pandemic

General features of the <i>L</i>. <i>borgpetersenii</i> serovar Ballum and serovar Hardjo genome.

<p>General features of the <i>L</i>. <i>borgpetersenii</i> serovar Ballum and serovar Hardjo genome.</p

Distribution of Plasmids in Distinct <i>Leptospira</i> Pathogenic Species

<div><p>Leptospirosis, caused by pathogenic <i>Leptospira</i>, is a worldwide zoonotic infection. The genus <i>Leptospira</i> includes at least 21 species clustered into three groups—pathogens, non-pathogens, and intermediates—based on 16S rRNA phylogeny. Research on <i>Leptospira</i> is difficult due to slow growth and poor transformability of the pathogens. Recent identification of extrachromosomal elements besides the two chromosomes in <i>L</i>. <i>interrogans</i> has provided new insight into genome complexity of the genus <i>Leptospira</i>. The large size, low copy number, and high similarity of the sequence of these extrachromosomal elements with the chromosomes present challenges in isolating and detecting them without careful genome assembly. In this study, two extrachromosomal elements were identified in <i>L</i>. <i>borgpetersenii</i> serovar Ballum strain 56604 through whole genome assembly combined with S1 nuclease digestion following pulsed-field gel electrophoresis (S1-PFGE) analysis. Further, extrachromosomal elements in additional 15 Chinese epidemic strains of <i>Leptospira</i>, comprising <i>L</i>. <i>borgpetersenii</i>, <i>L</i>. <i>weilii</i>, and <i>L</i>. <i>interrogans</i>, were successfully separated and identified, independent of genome sequence data. Southern blot hybridization with extrachromosomal element-specific probes, designated as lcp1, lcp2 and lcp3-<i>rep</i>, further confirmed their occurrences as extrachromosomal elements. In total, 24 plasmids were detected in 13 out of 15 tested strains, among which 11 can hybridize with the lcp1-<i>rep</i> probe and 11 with the lcp2-<i>rep</i> probe, whereas two can hybridize with the lcp3-<i>rep</i> probe. None of them are likely to be species-specific. Blastp search of the lcp1, lcp2, and lcp3-<i>rep</i> genes with a nonredundant protein database of <i>Leptospira</i> species genomes showed that their homologous sequences are widely distributed among clades of pathogens but not non-pathogens or intermediates. These results suggest that the plasmids are widely distributed in <i>Leptospira</i> species, and further elucidation of their biological significance might contribute to our understanding of biology and infectivity of pathogenic spirochetes.</p></div

Molecular Typing of Pathogenic <i>Leptospira</i> Serogroup Icterohaemorrhagiae Strains Circulating in China during the Past 50 Years

<div><p>Background</p><p>Leptospirosis is one of the most important neglected tropical infectious diseases worldwide. Icterohaemorrhagiae has been throughout recent history, and still is, the predominant serogroup of this pathogen in China. However, very little in detail is known about the serovars or genotypes of this serogroup.</p><p>Methodology/Principal Findings</p><p>In this study, 120 epidemic strains from five geographically diverse regions in China collected over a 50 year period (1958~2008), and 8 international reference strains characterized by 16S rRNA sequencing and MLST analysis. 115, 11 and 2 strains were identified as <i>L</i>. <i>interrogans</i>, <i>L</i>. <i>borgpetersenii</i>, and <i>L</i>. <i>kirschneri</i>, respectively. 17 different STs were identified including 69 ST1 strains, 18 ST17, 18 ST128, 9 ST143 and 2 ST209. The remaining 12 strains belonged to 12 different STs. eBURST analysis demonstrated that, among the clonal complexes isolated (CCs), CC1 accounted for 73.3% (88/120) strains representing three STs: ST1, ST128 and ST98. ST1 was the most likely ancestral strain of this CC, followed by singleton CC17 (17/120) and CC143 (11/120). Further analysis of adding 116 serogroup Icterohaemorrhagiae strains in the MLST database and studies previously described using global eBURST analysis and MST dendrogram revealed relatively similar ST clustering patterns with five main CCs and 8 singletons among these 244 strains. CC17 was found to be the most prevalent clone of pathogenic <i>Leptospira</i> circulating worldwide. This is the first time, to our knowledge, that ST1 and ST17 strains were distributed among 4 distinct serovars, indicating a highly complicated relationship between serovars and STs.</p><p>Conclusions/Significance</p><p>Our studies demonstrated a high level of genetic diversity in the serogroup Icterohaemorrhagiae strains. Distinct from ST17 or ST37 circulating elsewhere, ST1 included in CC1, has over the past 50 years or so, proven to be the most prevalent ST of pathogenic leptospires isolated in China. Moreover, the complicated relationship between STs and serovars indicates an urgent need to develop an improved scheme for <i>Leptospira</i> serotyping.</p></div

General features of the plasmids in sequenced pathogenic <i>Leptospira</i> genome.

<p>General features of the plasmids in sequenced pathogenic <i>Leptospira</i> genome.</p