The Continuous‐Time Lace Expansion Brydges, David; Helmuth, Tyler; Holmes, Mark
Communications on pure and applied mathematics,
November 2021, Letnik:
74, Številka:
11
Journal Article
We found that phase cone clustering patterns in EEG ripple bands demonstrate an increased turnover rate in epileptogenic zones compared to adjacent regions. We employed 256 channel EEG data collected ...in four adult subjects with refractory epilepsy. The analysis was performed in the 80-150 and 150-250 Hz ranges. Ictal onsets were documented with intracranial EEG recordings. Interictal scalp recordings, free of epileptiform patterns, of 240-s duration, were selected for analysis for each subject. The data was filtered, and the instantaneous phase was extracted after the Hilbert transformation. Spatiotemporal contour plots of the unwrapped instantaneous phase with 1.0 ms intervals were constructed using a montage layout of the 256 electrode positions. Stable phase cone patterns were selected based on criteria that the sign of spatial gradient did not change for a minimum of three consecutive time samples and the frame velocity was consistent with known propagation velocities of cortical axons. These plots exhibited increased dynamical formation and dissolution of phase cones in the ictal onset zones, compared to surrounding cortical regions, in all four patients. We believe that these findings represent markers of abnormally increased cortical excitability. They are potential tools that may assist in localizing the epileptogenic zone.
Mobile genetic elements (MGEs) are agents of horizontal gene transfer in bacteria, but can also be vertically inherited by daughter cells. Establishing the dynamics that led to contemporary patterns ...of MGEs in bacterial genomes is central to predicting the emergence and evolution of novel and resistant pathogens. Methicillin-resistant Staphylococcus aureus (MRSA) clonal-complex (CC) 398 is the dominant MRSA in European livestock and a growing cause of human infections. Previous studies have identified three categories of MGEs whose presence or absence distinguishes livestock-associated CC398 from a closely related and less antibiotic-resistant human-associated population. Here, we fully characterise the evolutionary dynamics of these MGEs using a collection of 1180 CC398 genomes, sampled from livestock and humans, over 27 years. We find that the emergence of livestock-associated CC398 coincided with the acquisition of a Tn916 transposon carrying a tetracycline resistance gene, which has been stably inherited for 57 years. This was followed by the acquisition of a type V SCCmec that carries methicillin, tetracycline, and heavy metal resistance genes, which has been maintained for 35 years, with occasional truncations and replacements with type IV SCCmec. In contrast, a class of prophages that carry a human immune evasion gene cluster and that are largely absent from livestock-associated CC398 have been repeatedly gained and lost in both human- and livestock-associated CC398. These contrasting dynamics mean that when livestock-associated MRSA is transmitted to humans, adaptation to the human host outpaces loss of antibiotic resistance. In addition, the stable inheritance of resistance-associated MGEs suggests that the impact of ongoing reductions in antibiotic and zinc oxide use in European farms on livestock-associated MRSA will be slow to be realised.
III-nitride quantum dots are proving to be promising for application to single photon emitting devices. Research around the globe is revealing several interesting properties of these emitters, ...including a wide range of emission wavelengths, high temperature operation, and deterministic polarization of the emitted photons. Here a review is given on the single photon emission properties of such III-nitride quantum dots.
The discovery of antibiotics more than 80 years ago has led to considerable improvements in human and animal health. Although antibiotic resistance in environmental bacteria is ancient, resistance in ...human pathogens is thought to be a modern phenomenon that is driven by the clinical use of antibiotics
. Here we show that particular lineages of methicillin-resistant Staphylococcus aureus-a notorious human pathogen-appeared in European hedgehogs in the pre-antibiotic era. Subsequently, these lineages spread within the local hedgehog populations and between hedgehogs and secondary hosts, including livestock and humans. We also demonstrate that the hedgehog dermatophyte Trichophyton erinacei produces two β-lactam antibiotics that provide a natural selective environment in which methicillin-resistant S. aureus isolates have an advantage over susceptible isolates. Together, these results suggest that methicillin resistance emerged in the pre-antibiotic era as a co-evolutionary adaptation of S. aureus to the colonization of dermatophyte-infected hedgehogs. The evolution of clinically relevant antibiotic-resistance genes in wild animals and the connectivity of natural, agricultural and human ecosystems demonstrate that the use of a One Health approach is critical for our understanding and management of antibiotic resistance, which is one of the biggest threats to global health, food security and development.
Using firm‐level data, this paper examines the effects of foreign investment on the exporting behaviour of domestic firms in the Vietnamese manufacturing and service sectors. Applying the Heckman ...selection model on panel data and following the Wooldridge approach, we find that investment by foreign firms has a significant positive effect on the decision of domestic firms in the same and upstream sectors to export. The proportion of exports of domestic firms declines through horizontal and forward linkages, but increases through backward linkages in the manufacturing sector. However, there is only weak evidence in support of export spillovers on domestic firms in the service sector. We also find that the presence of foreign firms has differing effects on the exporting activities of low‐ versus high‐tech firms in the manufacturing sector.
This paper investigates the long-run convergence of regional house prices in the UK. Existing studies have failed to reach a consensus on whether or not regional house prices exhibit long-run ...convergence with each other. The application is proposed of a new test involving unit root testing of the first principal component based on regional-national house price differentials. Using mix-adjusted quarterly data for 1973-2006, it is found that the first principal component is stationary. This suggests that all UK regional house prices are driven by a single common stochastic trend. Further analysis suggests that those regions that are more distant from London exhibit the highest degrees of persistence with respect to deviations in house price differentials.
The aim of this study was to investigate the genomic epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in China to identify predominant lineages and their associations with clinical ...data and antimicrobial resistance profiles.
We performed a national prevalence study of patients with S. aureus infections in 22 tertiary hospitals in China from 2015 to 2017. Clinical data from patients and the antimicrobial phenotypes were collected for each isolate. Genome sequencing was performed on a proportion of isolates and a phylogenetic analysis was undertaken. Genotypic and phenotypic β-lactam susceptibilities were compared.
A total of 1900 patients with S. aureus infections were included, of which 40% involved MRSA. Community-associated MRSA (CA-MRSA) infections were 24% of the total isolates. Genomic data showed that more than three-quarters of the MRSA were from three dominant lineages CC239 (25%, 116/471), CC5 (21%, 96/471) and CC59 (33%, 154/471) with CC59 accounting for more than half of the CA-MRSA isolates. Penicillin susceptibility genomic features were observed in 53% (251/470) of MRSA, including almost all of the CC59 (152/154) lineage, and 96% (242/251) of these isolates demonstrated in vitro susceptibility to penicillin or amoxicillin combined with clavulanic acid. Phylogenetic analysis indicated that the CC59 lineage can be divided into six lineages with all Asian CC59 isolates likely arising from an ancestral Mainland China lineage.
This study showed a high prevalence of CA-MRSA in China, largely due to the widespread presence of CC59. As almost all isolates in this lineage possess genetic variants leading to increased β-lactam susceptibility, we suggest that to improve antibiotic stewardship combinations of penicillins and β-lactamase inhibitors should be included in the antibiotic susceptibility testing panels used to inform treatment decisions and research undertaken on this combination therapy.
Staphylococcus aureus
is a ubiquitous organism that causes a variety of diseases including mastitis in cattle and humans. High-level resistance of
S. aureus
to β-lactams conferred by a
mecA
gene ...encoding a modified penicillin binding protein (PBP2a) was first observed in the early 1960’s. These methicillin resistant
S. aureus
(MRSA) have been responsible for both hospital acquired infections (HA-MRSA) and, more recently, community acquired MRSA (CA-MRSA). A small number of human MRSA mastitis cases and outbreaks in maternity or neonatal units have been reported which are generally the result of CA-MRSA. The establishment of the sequence type 398 (ST398) in farm animals, primarily pigs, in the early 2000’s has provided a reservoir of infection for humans and dairy cattle, particularly in continental Europe, described as livestock-associated MRSA (LA-MRSA). Prior to the emergence of ST398 there were sporadic reports of MRSA in bovine milk and cases of mastitis, often caused by strains from human associated lineages. Subsequently, there have been several reports describing bovine udder infections caused by ST-398 MRSA. Recently, another group of LA-MRSA strains was discovered in humans and dairy cattle in Europe. This group carries a divergent
mecA
gene and includes a number of
S. aureus
lineages (CC130, ST425, and CC1943) that were hitherto thought to be bovine-specific but are now also found as carriage or clinical isolates in humans. The emergence of MRSA in dairy cattle may be associated with contact with other host species, as in the case of ST398, or with the exchange of genetic material between
S. aureus
and coagulase negative
Staphylococcus
species, which are the most common species associated with bovine intramammary infections and commonly carry antimicrobial resistance determinants.
Pork accounts for the largest proportion of meat consumed globally and demand is growing rapidly. Two important externalities of pig farming are land use and antimicrobial resistance (AMR) driven by ...antimicrobial use (AMU). Land use and AMU are commonly perceived to be negatively related across different production systems, so those with smaller land footprints pose greater risk to human health. However, the relationship between land use and AMU has never been systematically evaluated. We addressed this by measuring both outcomes for 74 highly diverse pig production systems. We found weak evidence of an AMU/land use tradeoff. We also found several systems characterized by low externality costs in both domains. These potentially promising systems were spread across different label and husbandry types and indeed no type was a reliable indicator of low-cost systems in both externalities. Our findings highlight the importance of using empirical evidence in decision-making, rather than relying on assumptions.
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