Optical Hall conductivity of systems with gapped spectral nodes

We calculate the optical Hall conductivity within the Kubo formalism for systems with gapped spectral nodes, where the latter have a power-law dispersion with exponent n. The optical conductivity is proportional to n and there is a characteristic logarithmic singularity as the frequency approaches the gap energy. The optical Hall conductivity is almost unaffected by thermal fluctuations and disorder for n=1, whereas disorder has a stronger effect on transport properties if n=2

Схиигумен Сергий как маргинальная языковая личность в пространстве религиозно-политической коммуникации

SummaryThaumarchaeota are globally distributed and abundantmicroorganisms occurring in diverse habitats and thusrepresent a major source of archaeal lipids. The scopeof lipids as taxonomic markers in microbial ecologicalstudies is limited by the scarcity of comparative dataon the membrane lipid composition of cultivated representatives,including the phylum Thaumarchaeota.Here, we comprehensively describe the core and intactpolar lipid (IPL) inventory of ten ammonia-oxidisingthaumarchaeal cultures representing all four characterizedphylogenetic clades. IPLs of these thaumarchaealstrains are generally similar and consist of membranespanning,glycerol dibiphytanyl glycerol tetraetherswith monoglycosyl, diglycosyl, phosphohexose andhexose-phosphohexose headgroups. However, the relativeabundances of these IPLs and their core lipidcompositions differ systematically between the phylogeneticsubgroups, indicating high potential forchemotaxonomic distinction of thaumarchaeal clades.Comparative lipidomic analyses of 19 euryarchaeal andcrenarchaeal strains suggested that the lipid methoxyarchaeol is synthesized exclusively by Thaumarchaeotaand may thus represent a diagnostic lipidbiomarker for this phylum. The unprecedented diversityof the thaumarchaeal lipidome with 118 differentlipids suggests that membrane lipid composition andadaptation mechanisms in Thaumarchaeota are morecomplex than previously thought and include uniquelipids with as yet unresolved properties

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

A molecular analysis of Archaeal community structure and activity in grassland rhizosphere soil

Available from British Library Document Supply Centre-DSC:DXN053109 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Influence of soil pH on the abundance and distribution of core and intact polar lipid-derived branched GDGTs in soil

Branched glycerol dialkyl glycerol tetraether (GDGT) lipids occur in soils worldwide and are presumed to be produced by soil bacteria. They form the base of the MBT/CBT proxy (methylation of branched tetraethers/cyclisation of branched tetraethers) for palaeoclimate reconstruction. The degree of cyclisation and methylation, expressed in the CBT and MBT indices, has been shown to relate to soil pH, and to both temperature and soil pH, respectively. To evaluate the direct impact of soil pH on the abundance and distribution of branched GDGTs, either present as core lipids or derived from intact polar lipids (IPLs), long term (>45 years) soil pH manipulation plots, with a pH range of 4.5–7.5, were analyzed. The CBT index values of both core and IPL-derived branched GDGTs was significantly (r2 = 0.93, P = 0.0004 and r2 = 0.93, P = 0.0005, respectively) linearly related to actual soil pH, confirming the direct influence of pH on the distribution of branched GDGT. In contrast, the MBT index was only influenced to a minor extent by the changes in soil pH. Branched GDGT abundances decreased with increasing soil pH, supporting the idea that Acidobacteria may be a possible source of these orphan membrane lipids

Influence of soil pH on the abundance and distribution of core and intact polar lipid-derived branched GDGTs in soil

Branched glycerol dialkyl glycerol tetraether (GDGT) lipids occur in soils worldwide and are presumed to be produced by soil bacteria. They form the base of the MBT/CBT proxy (methylation of branched tetraethers/cyclisation of branched tetraethers) for palaeoclimate reconstruction. The degree of cyclisation and methylation, expressed in the CBT and MBT indices, has been shown to relate to soil pH, and to both temperature and soil pH, respectively. To evaluate the direct impact of soil pH on the abundance and distribution of branched GDGTs, either present as core lipids or derived from intact polar lipids (IPLs), long term (>45 years) soil pH manipulation plots, with a pH range of 4.5–7.5, were analyzed. The CBT index values of both core and IPL-derived branched GDGTs was significantly (r2 = 0.93, P = 0.0004 and r2 = 0.93, P = 0.0005, respectively) linearly related to actual soil pH, confirming the direct influence of pH on the distribution of branched GDGT. In contrast, the MBT index was only influenced to a minor extent by the changes in soil pH. Branched GDGT abundances decreased with increasing soil pH, supporting the idea that Acidobacteria may be a possible source of these orphan membrane lipids

Quantitative assessment of ammonia-oxidizing bacterial communities in the epiphyton of submerged macrophytes in shallow lakes

In addition to the benthic and pelagic habitats, the epiphytic compartment of submerged macrophytes in shallow freshwater lakes offers a niche to bacterial ammonia-oxidizing communities. However, the diversity, numbers, and activity of epiphytic ammonia-oxidizing bacteria have long been overlooked. In the present study, we analyzed quantitatively the epiphytic communities of three shallow lakes by a potential nitrification assay and by quantitative PCR of 16S rRNA genes. On the basis of the m2 of the lake surface, the gene copy numbers of epiphytic ammonia oxidizers were not significantly different from those in the benthic and pelagic compartments. The potential ammonia-oxidizing activities measured in the epiphytic compartment were also not significantly different from the activities determined in the benthic compartment. No potential ammonia-oxidizing activities were observed in the pelagic compartment. No activity was detected in the epiphyton of Chara aspera, the dominant submerged macrophyte in Lake Nuldernauw in The Netherlands. The presence of ammonia-oxidizing bacterial cells in the epiphyton of Potamogeton pectinatus was also demonstrated by fluorescent in situ hybridization microscopy images. By comparing the community composition as assessed by the 16S rRNA gene PCR-denaturing gradient gel electrophoresis approach, it was concluded that the epiphytic ammonia-oxidizing communities consisted of cells that were also present in the benthic and pelagic compartments. Of the environmental parameters examined, only the water retention time, the Kjeldahl nitrogen content, and the total phosphorus content correlated with potential ammonia-oxidizing activities. None of these parameters correlated with the numbers of gene copies related to ammonia-oxidizing betaproteobacteri

Effects of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on the activity and diversity of the soil microbial community under contrasting soil pH

The impact of DMPP (3,4-dimethylpyrazole phosphate), applied at two doses (low: recommended for agronomic use; high: > 100 × the recommended), on the function, diversity, and dynamics of target microorganisms (ammonia-oxidizing microorganisms, AOM), functionally associated microorganisms (nitrite-oxidizing bacteria (NOB) and denitrifiers), and total prokaryotic and fungal microbial communities was assessed in two loamy soils, mainly differing in pH (acidic vs. alkaline), in a 35-day microcosm study. This was achieved via monitoring inorganic N-pools, potential nitrification (PN) rates, amoA gene and transcripts abundance, the abundance of other phylogenetic marker genes (nxrB, narG, nirS, nirK, nosZ, 16S rRNA, 18S rRNA), and amplicon sequencing of amoA, 16S rRNA, and ITS. Overall, DMPP was more persistent in the acidic soil. Its low dose successfully inhibited nitrification in the alkaline but not in the acidic soil, where effective inhibition was observed only at the high dose. This was mainly attributed to the consistently higher activity of DMPP towards ammonia-oxidizing bacteria (AOB) prevailing in the alkaline soil, unlike ammonia-oxidizing archaea (AOA) whose abundance and transcriptional activity was reduced only by the high dose. DMPP, at the high dose, reduced the abundance of Nitrobacter but not Nitrospira NOB, while its low dose increased the abundance of denitrifying bacteria, prokaryotic, and fungal populations in the alkaline soil. Amplicon sequencing revealed that DMPP imposed significant changes in the composition of the prokaryotic, fungal, and AOB communities in both soils, unlike AOA which were less responsive. These were associated with dose-dependent changes in the abundance of bacteria and fungi known to control key soil functions implying possible effects for the soil ecosystem homeostasis. Our study paves the way for a more comprehensive analysis of the effects of NIs on the soil microbial community, beyond the current focus on target AOM. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature