Branch Research Articles

A machine learning approach to rank pricing problems in branch-and-price

This paper presents a novel approach exploiting machine learning to enhance the efficiency of the branch-and-price algorithm. The focus is, specifically, on problems characterized by multiple pricing problems. Pricing problems often constitute a substantial portion of CPU time due to their repetitive nature. The primary contribution of this work includes the introduction of a machine learning-based ranker that strategically guides the search for new columns in the column generation process. The master problem solution is analyzed by the ranker, which then suggests an order for solving the pricing problems to prioritize those with the potential to improve the master problem the most. This prioritization mechanism is essential in speeding up the column generation since, by identifying new columns early in the process, we can terminate the search procedure sooner. Furthermore, our technique exhibits applicability across all nodes of the branching tree, making it a valuable tool for solving a wide range of optimization problems. We demonstrate the usefulness of this approach in the challenging domain of operating room scheduling, an area that has seen limited exploration in the context of machine learning. Extensive experimental evaluations underline the effectiveness of the developed algorithm, consistently outperforming traditional search strategies in terms of time, number of solved pricing problems, searched nodes in the branching tree, and performed column generation iterations.

The Establishment of Complement System Is from Gene Duplication and Domain Shuffling.

The mammalian complement system constitutes a highly sophisticated body defense machinery. The evolutionary origin of the complement system can be traced to Coelenterata as the presence of the central component C3 and two activation proteases BF and MASP. In the present study, the main complement components were screened and analyzed from the genomes of different species in metazoan subphyla/phyla. C1q with classical domains can be traced to Annelida, and ficolin and MBL to Urochordata. C1r and C1s are only found in Chondrichthyes and even higher species, and MASP is traced to Coelenterata. In the evolutionary tree, C1r from Vertebrates is close to MASP1/2/3 from Deuterostomia and Coelenterata, and C1s from Vertebrates is close to MASP-like protease (MASPL) from Arthropoda, Mollusca, and Annelida. C2, BF, and DF can be traced to Mollusca, Coelenterata, and Porifera, respectively. There are no clear C2 and BF branches in the evolutionary tree. C3 can be traced to Coelenterata, and C4 and C5 are only in Chondrichthyes and even higher species. There are three clear C3, C4, and C5 branches in the evolutionary tree. C6-like (C6L) and C8 can be traced to Urochordata, and C7-like (C7L) can be traced to Cephalochordara. C6L, C7L, and C8 from Urochordata and Cephalochordara provide the structural conditions for the formation of Vertebrate MAC components. The findings unveil the evolutionary principles of the complement system and provide insight into its sophistication.

Magnetic resonance lymphography findings across different clinical stages of lower limb lymphedema

ObjectiveTo investigate the imaging findings of lower limb lymphedema using magnetic resonance lymphography (MRL). MethodsMRL was used to record the lymphatic vessel morphology, distribution of lymphatic vessels, dermal backflow (DBF), and morphology of inguinal lymph nodes in 112 patients (175 affected limbs) with the lower limb lymphedema at different clinical stages (according to the International Society of Lymphology staging criteria 2020). ResultsThe lymphatic vessel morphology significantly differed in different clinical stages (X2=59.306; P=0.000). ISL stage I is dominated by ‘scattered beads’ and ‘branch-like’ distribution, ISL stage Ⅱ has tree branch or ‘capillary-like’ distribution, and ISL stage Ⅲ primarily has a capillary pattern and contrast agent accumulation in the foot. There were statistically significant differences in the distribution of lymphatic vessels and DBF in different clinical stages. The distribution of enhanced lymphatic vessels was distal to the knee in ISL stage I, involved areas below the knee joint or involving the whole limb in ISL stage II, and Involving the whole limb in ISL stage III (X2=44.591; P=0.000). With the progression of edema, DFB severity increased (X2=76.416; P=0.000). ConclusionMRL revealed the morphology and distribution of lymphatic vessels and detected abnormal inguinal lymph nodes in patients at different stages of lymphedema, which can provide reference information for surgical treatment.

Juvenile instars of Sellnickia caudata (Michael, 1908) (Acari, Oribatida, Sellnickiidae)

Juvenile instars of Sellnickia caudata (Michael, 1908) are described, based on specimens collected from tree branches and leaves of Dipterocarpus alatus in Vietnam.

The distribution of Apis laboriosa revisited: range extensions, biogeographic affinities, and species distribution modelling

IntroductionApis laboriosa, the Himalayan giant honeybee, inhabits the foothills of Himalaya and neighboring mountainous regions. Here we revise its distribution in light of recent reports and discoveries, review the ecozones it inhabits, and reassess its likely distribution through species distribution modeling.MethodsWe revised the range map for A. laboriosa by mapping locality records from various sources: refereed research publications, museum specimens, records with identifiable images of bees in publicly available databases, personal observations of the authors, and photos/videos and their coordinates submitted to the authors by honey-hunters, beekeepers, and extension workers. We then used that map to determine the ecozones in which the species occurs. The geographical coordinates of the data localities were used to estimate the potential suitable areas for the bee with MaxEnt modeling.ResultsOur research filled in several previously identified gaps in the distribution of A. laboriosa: in western Nepal; mountainous regions of Myanmar, northwestern Thailand, and northern Laos; several river valleys in Xizang and Yunnan, China; and northeastern Pakistan. Over most of its range this bee species primarily occupies subtropical broadleaf forests with strong Himalayan affinities. However, in the western part of its range it extends into zones dominated by conifers. The sites where A. laboriosa has been recorded closely match the predicted range of the species. Two variables, mean temperature of the coldest quarter and temperature seasonality, contributed most (76%) to the species distribution model.DiscussionApis laboriosa has a more extensive distribution in the foothills of the Himalaya and neighboring mountainous regions than has been previously recognized. The range now extends from longitude 74.4°–105.9°E, a linear distance of 3300 km, and from latitude 19.2°N–34.8°N. We have documented nesting on tree branches in northern Vietnam. Future research is warranted on its elevational migrations along river valleys, population differentiation, and ecological role as a pollinator in the different ecological zones it inhabits.

Accumulation of airborne microplastics on leaves of different tree species in the urban environment

Microplastics (MPs) are omnipresent in the environment and they are linked to ecosystem and human health problems. The atmospheric transport of MPs and the role of tree leaves in MP atmospheric deposition has not been adequately studied. MP concentrations on the leaves of different tree species in urban regions of the Netherlands and Portugal, along with related MP deposition, were investigated in this study. We collected leaves from cedar, eucalyptus, oak, pine and willow trees, together with monthly deposition of particles under the trees and in the open space in Coimbra (Portugal). In Wageningen (the Netherlands), we collected leaves from a fir and a holly tree at different heights above the ground and with dry and wet weather conditions. MPs were extracted through density separation and quantified under a microscope. Polymer types were identified using μ-FTIR. The results showed a higher number of MP particles on the needle-shaped leaves from fir (2.52 ± 2.14 particles·cm−2) and pine (0.5 ± 0.13 particles·cm−2) and significantly lower numbers of MPs per cm2 of leaf area on the bigger leaves from eucalyptus (0.038 ± 0.003 particles·cm−2) and cedar (0.037 ± 0.002 particles·cm−2). All tree leaves seemed to filter airborne MPs, especially the smallest particles. A non-significantly higher number of particles on leaves was detected on lower tree branches and after dry periods. The deposition of MPs under trees was generally higher than in the open space. Our results indicated that part of the MPs retained by the tree leaves floats down to lower branches and to the soil surface. We also saw that different tree species had different capacities to retain particles on their leaves over time. To control the transport of MPs through the atmosphere, it is essential to consider the role of different vegetation types in filtering small particles, especially in cities.

Machine learning-assisted wood materials: Applications and future prospects

Wood and wood-based materials, surpassing their conventional image as mere stems and branches of trees, have found extensive utilization in diverse industrial sectors due to their low carbon footprint. Nonetheless, maximizing wood utilization and advancing multifunctional wood materials face challenges due to resource-intensive conventional approaches. Integrating machine learning (ML) in wood mechanics has emerged as a promising avenue for deeper exploration of this remarkable material. By leveraging advanced computational techniques, researchers can delve into wood's intricate properties and behavior, unraveling the complex interactions between its chemical constituents, microstructures, and mechanical characteristics. Combined with imaging and sensor technologies, ML contributes to efficient, fast, and real-time health detection of wood materials. This review aims to illuminate the transformative impact of ML in unlocking the hidden potential of wood, fostering innovative applications, and facilitating sustainable engineering solutions. The basic workflow of ML and its typical applications in property prediction, defect detection, and optimized design of wood materials are discussed, thereby highlighting the challenges and the need for future research.

Aspergillus Endophthalmitis Secondary to Infectious Scleritis: Utility of Diagnostic PCR.

To describe a case of delayed-onset Aspergillus fumigatus endophthalmitis secondary to infectious fungal scleritis diagnosed with broad range polymerase chain reaction (PCR) from scleral nodular debridement and vitreous sampling during vitrectomy. Retrospective case report with slit lamp photography, optical coherence tomography, and fundus photography. A 76-year-old man presented with right eye worsening vision and pain concerning for progressive nodular scleritis and endophthalmitis eight months following a reportedly innocuous tree branch injury. Following the injury, he underwent an MRI, surgical exploration, subconjunctival antibiotic administration, and culturing due to persistent foreign body sensation. Cultures were negative, and the patient was started on oral NSAIDs, oral prednisone, and periocular triamcinolone injections following negative/normal infectious and rheumatologic workup for scleritis. The patient was referred for worsened scleritis with development of endophthalmitis. He underwent lamellar sclerectomy, debridement, and culture of purulent material from scleral nodules in coordination with diagnostic vitrectomy, vitreous sampling, and subconjunctival and intravitreal antibiotic and antifungal treatment. Broad range PCR was positive for Aspergillus fumigatus and targeted antifungal treatment initiated. The eye did not regain visual function and was enucleated for progressive pain six months following diagnosis. Fungal scleritis and endophthalmitis results in significant morbidity. Diagnostic vitrectomy and broad range PCR can aid in prompt diagnosis and targeted treatment, and may be useful in refractory cases.

Regional variation in branch morphological and physical traits in Abies sachalinensis associated with winter climatic conditions

ABSTRACT In boreal forests, overwintering strategies, including snow adaptation, can be expected in the branches of coniferous trees. Although it is difficult to detect resistance to snow disturbances and few studies have quantified the functional traits related to snowfall resistance, the regional variation associated with winter conditions may provide cues for identifying adaptive traits against snow damage. In common garden trials, we examined the regional variation in branch functional traits in Abies sachalinensis, one of the most important conifers in boreal forest silviculture. Morphological traits reflecting susceptibility to snow accumulation, such as branch estimated area, Young’s modulus and flexural rigidity, which represent deformability to snow loads, and base diameter and xylem density were evaluated in five-year-old branches from eight provenances. The length and estimated area of a branch showed regional variation. Significant regional variation in flexural rigidity rather than Young’s modulus and no significant correlation between xylem density and mechanical traits indicated that the physical properties of branches depend on their size rather than on their materials. A significant correlation with winter climatic conditions was observed between flexural rigidity and total monthly precipitation in January. Our results showed that the thicker the branch is, the larger the branch area and the more rigid it is. This indicates that the branch size-dependent resistance to snow loads might be associated with winter adaptation to local snowfall conditions.

Allelopathy and Allelochemicals in Chamaecyparis obtusa Leaves for the Development of Sustainable Agriculture

Chamaecyparis obtusa (Siebold et Zucc.) Endl. is cultivated in the temperate region of East Asia for its high-quality and profitable timber. The timber-processing industry produces a large amount of waste, such as tree bark, branches, and leaves, and finding ways to minimize such waste is economically and environmentally efficient. In the present study, the allelopathic activity and allelochemicals of the C. obtusa leaves were investigated to develop potential application methods. C. obtusa leaves were phytotoxic and associated leaf extracts significantly suppressed the growth of the weeds; Echinochloa crus-galli, Phleum pratense and Lolium multiflorum under laboratory conditions. The leaf powder applied onto the soil surface also suppressed the germination of E. crus-galli and P. pratense under greenhouse conditions. Hinokiic acid and (+)-dihydrosesamin were isolated from the leaves and structurally identified. Both compounds suppressed the growth of cress and P. pratense in a concentration dependent manner. When the leaves of C. obtua were applied as a soil additive, hinokiic acid and (+)-dihydrosesamin in the leaves potentially cause the growth inhibitory activity by leaching into the soil. These experiments showed that the leaves and the leaf extracts of C. obtusa are phytotoxic. These experiments also demonstrated that the leaves and the leaf extracts of C. obtusa have growth inhibitory potential against several plant species, and the leaves produce allelochemicals. Therefore, the leaves and leaf extracts of C. obtusa may be useful for weed suppression purposes. The leaf biomass of C. obtusa is frequently large and the timber processing industry produces significant leaf waste. The development of weed control products using waste leaves may be a solution to minimize the timber processing waste to reduce environmental impact and provide economic value. However, leaf material should be evaluated for weed suppression and herbicidal activity as a soil additive and also possible as a foliar spray under field conditions.

Taller trees exhibit greater hydraulic vulnerability in southern Amazonian forests

Potential increases in drought frequency and vapour pressure deficit pose a risk to the future function of tropical trees. Previous studies have found that taller tropical trees show a stronger increase in mortality than shorter trees in response to dry anomalies, but the mechanisms behind this are unclear. Here we investigate whether canopy branches of taller tropical trees have different hydraulic traits compared to shorter conspecifics. We determined xylem resistance to embolism (P50), hydraulic safety margin (HSM), xylem functional traits and xylem theoretical hydraulic conductivity for canopy branches of four tree species across a range of tree heights (sapling to maximum tree height) in an ecotonal forest near the Amazonia-Cerrado transition. We found that canopy branches of taller trees within each species have lower HSM, suggesting that they are more susceptible to hydraulic failure under drought than smaller conspecifics. Height-related trends in HSM were driven by variation in P50 with height and not by variation in leaf water potential which did not vary with height. We find that canopy branches with greater xylem vessel diameters are generally more vulnerable to embolism, suggesting a potential role for a diameter-safety linkage in explaining observed patterns of decreasing HSM with height. However, we find no evidence of a branch-level trade-off between theoretical hydraulic conductivity and hydraulic vulnerability. The greater hydraulic vulnerability of larger trees provides a potential explanation for the higher drought-induced mortality observed in taller tropical trees. The consistency of the height-P50 relationship across species opens the door to a more accurate prediction of southern Amazon forest responses to future droughts. Whether the findings for forests in southern Amazonia can be generalized to other Amazonian regions remains an open question.

Comparing YOLOv8 and Mask R-CNN for instance segmentation in complex orchard environments

Instance segmentation, an important image processing operation for automation in agriculture, is used to precisely delineate individual objects of interest within images, which provides foundational information for various automated or robotic tasks such as selective harvesting and precision pruning. This study compares the one-stage YOLOv8 and the two-stage Mask R-CNN machine learning models for instance segmentation under varying orchard conditions across two datasets. Dataset 1, collected in dormant season, includes images of dormant apple trees, which were used to train multi-object segmentation models delineating tree branches and trunks. Dataset 2, collected in the early growing season, includes images of apple tree canopies with green foliage and immature (green) apples (also called fruitlet), which were used to train single-object segmentation models delineating only immature green apples. The results showed that YOLOv8 performed better than Mask R-CNN, achieving good precision and near-perfect recall across both datasets at a confidence threshold of 0.5. Specifically, for Dataset 1, YOLOv8 achieved a precision of 0.90 and a recall of 0.95 for all classes. In comparison, Mask R-CNN demonstrated a precision of 0.81 and a recall of 0.81 for the same dataset. With Dataset 2, YOLOv8 achieved a precision of 0.93 and a recall of 0.97. Mask R-CNN, in this single-class scenario, achieved a precision of 0.85 and a recall of 0.88. Additionally, the inference times for YOLOv8 were 10.9 ms for multi-class segmentation (Dataset 1) and 7.8 ms for single-class segmentation (Dataset 2), compared to 15.6 ms and 12.8 ms achieved by Mask R-CNN's, respectively. These findings show YOLOv8's superior accuracy and efficiency in machine learning applications compared to two-stage models, specifically Mask-R-CNN, which suggests its suitability in developing smart and automated orchard operations, particularly when real-time applications are necessary in such cases as robotic harvesting and robotic immature green fruit thinning.

Primeiros socorros e transporte de equinos com emergência ortopédica: O que vale a pena saber!

Horses are considered prey in nature and, because of this, they have anatomical and physiological characteristics that facilitate their escape. However, they can suffer milder orthopedic accidents such as abrasions when encountering damaged fences, injuries from tree branches or even fractures when falling into ditches or wells. The objective of this article is to describe step-by-step first aid, including pain management, preparation for rescue, and transport to a reference center so that the owner, veterinarian and/or rescuer can manage this animal safely, quickly and assertively.

A morphological observation on the Cenozoic beetle Elektrocateres rappsilberi gen. et sp. nov. (Lophocateridae) using digital microscopy and synchrotron X-ray microtomography

ABSTRACT Elektrocateres rappsilberi gen. et sp. nov. is described from Bitterfeld or Saxonian amber. It is the first representative of the superfamily Cleroidea (Coleoptera) recorded in this amber, from which only 10 families of beetles were known until now. The new genus and species was studied using classical stereomicroscopy, as well as digital microscopy and synchrotron-radiation-based micro-computed tomography. The fossil is related to the rare extant monotypic genera Trichocateres Kolibáč, 2010 and Carinicateres Kolibáč, 2021 from tropical forests of Southeastern Asia. It is assumed that Elektrocateres rappsilberi gen. et sp. nov. would be predatory, hunting other arthropods on tree branches and trunks; however, its mouthparts are probably still on halfway between herbivory or fungivory and predatory.

Interpretable extreme wind speed prediction with concept bottleneck models

Concept-bottleneck models (CBMs) are a new paradigm to construct interpretable classifiers. The CBM architecture can be regarded as a neural network with a single hidden layer whose neurons are replaced by binary classifiers. Each of these binary classifiers implements a concept, that is, it attempts to answer a meaningful yes/no question: the presence or absence of a concept in the observation presented to the network. The output layer is usually implemented as a linear stage that combines the concepts into final decisions. This paper presents an application of the CBM paradigm to a problem of Extreme Wind Speed prediction, such that the forecasting properties of the system can be interpreted in terms of different concepts considered for this problem. A significant contribution of this paper is the proposal of an automated concept generation method, with controlled sparsity, in which the concepts are automatically extracted from the branches of decision trees fitted with informative features that capture the dynamics of the wind speed time series. The final forecasting system is able to predict extreme wind speed values in wind farms with good accuracy and interpretable results, as experiments over real wind speed data from a wind farm in Spain show.

Crops dependency on pollinators to secure pollination success and fruit development: A case study of almond varieties from Morocco

AbstractThe contribution of insects to pollination constitutes a globally important ecosystem service. Due to the increasing demand for entomophilous crops, the nutritional and economic importance of insect‐pollinated crops and the inability of managed pollinators (Apis mellifera L) to meet the high demand for their services indicate that agriculture heavily relies on wild pollinators. Almonds are an economically valuable crop in Morocco. Therefore, it is essential to understand the fundamental pollination requirements of major almond varieties to promote their production. The main objectives of this study were to assess the dependency of three almond cultivars (Espoir, Largueta and Planeta) on insect pollination, and then to evaluate the pollination deficit resulting from the lack of these pollinators. For this purpose, we used insect‐proof net bags constructed around branches of almond trees to compare fruit set and yield with open and open + hand‐pollinated flowers. The results of the fruit set experiment confirmed that all three varieties require insect pollination, as fruit set and yield were significantly higher in insect‐pollinated than insect‐isolated trees. All three almond varieties were categorized as obligatory dependent on biotic pollinators. In addition, two out of the three studied almond varieties showed high pollination deficit resulting from the lower abundance and/or diversity of pollinating insects. The results of the current study highlights the important role of insect pollinators for almond crops and the urgent need for the implementation of sustainable strategies to preserve pollinators within agricultural ecosystems.

Synergistic enhancement of regeneration capacity and ecological functions of Robinia pseudoacacia L. plantations in the Loess Plateau

Contemporary forestry research prioritizes the advancement of high-quality forestry, especially in ecologically vulnerable areas. To this end, enhancing the ecological function and natural regeneration capacity of planted forest stands is crucial. This study investigated synergistic or trade-off relationships between stand regeneration capacity and the ecological functions (including water conservation, soil conservation, carbon sequestration, and understory plant diversity) of Robinia pseudoacacia L. (RP) plantations in the Caijiachuan watershed of the Loess Plateau using Root Mean Square Deviation. The results indicated that stand regeneration capacity exhibited synergistic, moderate trade-off, and high trade-off relationships with soil and water conservation, stand carbon sequestration, and understory plant diversity, respectively. Notably, stand regeneration capacity had a synergistic relationship with the overall forest ecological function (sum of the above functions), suggesting that the overall forest ecological function can be simultaneously improved by enhancing stand regeneration capacity. Redundancy analyses revealed that the regeneration capacity was primarily influenced by soil moisture content (SMC), stand density (SD), total transmitted light, herbaceous species richness, litter accumulation, and soil available phosphorus (AP). According to the stand optimization model, the highest regeneration capacity of RP was observed under the following conditions: 1742 trees·hm−2 for SD, 15.29 % for SMC (higher than the mean value of 33.53 % for the existing RP), 41.69 mg·kg−1 for AP (higher than the mean value of 15.84 %), and 1.84 for LAI (lower than the mean value of 20.0 %). Therefore, to achieve the simultaneous enhancement of the regeneration capacity and overall ecological function of RP stands, foresters should prioritize adjusting SD to an appropriate range through thinning or replanting. Additionally, regular pruning of specific branches of individual trees is essential to mitigate the adverse effects of high LAI on stand regeneration. Where feasible, soil moisture and nutrients can also be increased, but excessive levels of AP should be avoided.

Habitat Characteristics of the Endangered Himalayan Red Panda in Panchthar–Ilam–Taplejung Corridor, Eastern Nepal

The Panchthar–Ilam–Taplejung Corridor in Eastern Nepal, managed through community forestry, is a crucial habitat for the Himalayan red panda, an endangered carnivore threatened by forest degradation and illegal trade. We deployed the altitude line intercept and ten-tree plotless methods to evaluate the distribution of Himalayan red pandas and the environmental factors affecting them within four community forests, namely Singhadevi, Chitre-Hile, Chhipchhipe, and Kalikhop-Dadehli, of the corridor. We established a total of 23 transects and 92 plots, identifying 41 plots with evidence of the Himalayan red panda’s presence. The sign occurrence revealed a clumped distribution of the species across all four community forests. The Himalayan red panda signs were observed between 2200 m and 2700 m above sea level (asl) and the majority of them were from habitats with a moderate slope within elevations of 2400 m to 2500 m asl. The primary sites for the defecation were large horizontal tree branches (78.12%), followed by forest ground (15.62%) and rocks (6.25%). The dominant tree species in their habitats included Lithocarpus pachyphylla (Importance value index, IVI = 45.05), Symplocus theifolia (IVI = 37.19), Symplocos pyrifolia (IVI = 20.99), Quercus lamellosa (IVI = 19.25), and Magnolia campbellii (IVI = 17.25). Among the thirteen environmental variables examined, proximity to water, distance to road, bamboo density, and Normalized Difference Vegetation Index were identified as the major factors influencing the Himalayan red panda’s distribution. This research provides crucial insights to develop site-specific habitat management plans for community forestry.

Genomic and Phenotypic Analysis of bla KPC-2 Associated Carbapenem Resistance in Klebsiella aerogenes: Insights into Clonal Spread and Resistance Mechanisms Across Hospital Departments in Beijing.

This study conducted an phenotypic and whole-genome sequencing analysis with Klebsiella aerogenes to elucidate its clinical epidemiological characteristics, antimicrobial resistance (AMR) phenotype, biofilm formation ability and hemolytic activity testing, AMR genes and phylogenetic relationships, so as to provide a further understanding of the intra-hospital strain transmission. Samples were collected from a hospital in Beijing between 2020 and 2022. All strains underwent bacterial identification, antimicrobial susceptibility testing (AST) using the VITEK-2 compact system. Biofilm formation ability and hemolytic activity were tested. Second-generation sequencing was applied to all strains, with those carrying the bla KPC gene were selected for third-generation sequencing. Whole-genome analysis identified resistance genes, plasmid types, MLST typing, and phylogenetic relationships. Plasmids were assembled to detect plasmid structures and AMR gene location. Among the 42 K. aerogenes isolates, 21 were carbapenem-resistant K. aerogenes (CRKA). All strains exhibited strong biofilm formation and no hemolytic activity. Most were sourced from sputum (83.3%). CRKA demonstrated extensive resistance to antibiotics, particularly β-lactamase inhibitors and Cefotetan. This resistance pattern was closely associated with the presence of an IncFII(pHN7A8) plasmid, which carried multiple resistance genes, including bla KPC-2, bla CTX-M-65, bla TEM-1, rmtB and a large number of mobile elements. The majority of CRKA strains clustered within the same branch of the phylogenetic tree, exhibiting minimal single nucleotide polymorphism (0-13 SNPs) differences, and they shared the same sequence type (ST292), resistance genes, and plasmids, originating from different departments, suggesting clonal transmission among the hospital. Our research reveals that the clonal transmission of CRKA occurs across various departments within the hospital. The widespread resistance observed in CRKA, attributed to the presence of bla KPC and ESBLs genes, underscores the need for heightened vigilance to prevent the further dissemination of CRKA within the hospital and, potentially, throughout the wider community.

Analysis of AC Filter Tripping Accident based on UHV Converter Station

Abstract An AC filter tripping accident occurred in a converter station of the North China Power Grid in 2019, which seriously affected the safe and stable operation of the power grid. In this paper, combined with the configuration of the AC filter in the converter station and the principle of capacitor unbalance protection, the tripping mechanism of the AC filter is explained. It is considered that the direct cause of the tripping of the AC filter is the short-circuit discharge phenomenon between the layers caused by the dead trees (grass) branches on the capacitor tower, which causes the instantaneous fault between the layers of the low-voltage capacitor, and finally leads to the action of the capacitor unbalance protection. From the perspective of operation and maintenance, some practical preventive measures are put forward, which will help to improve the safety of AC filter operation in the future, and then improve the reliability of DC transmission system, especially during the peak summer, peak winter and special power protection period, to ensure that there will be no fluctuation in DC load transmission and protect the safe and stable operation of power grid.