Trace element problems on Scottish soils.

The soils of Scotland are varied and relatively young, developed from glacial tills laid down about 12 000 years ago. The complex geology has produced varied trace element contents, usually related directly to their contents in the parent rock. Many of these elements are mobilized readily in soils with impeded drainage. Deficiencies of Co, Cu, Mn, B and Se have been recorded in plants or animals. Mo and Ni levels occasionally cause problems in animals and plants respectively. The trace element status of a soil can seldom be related to its total content: an extraction technique appropriate to the element in question is used to assess availability to plants. The Soil Survey of Scotland has reached the stage at which soil associations and soil series can be used to assess the probable trace element situation, particularly on arable land. Trace element contents of soils and plants are determined largely by spectrochemical methods. 19 references. (Abstract retrieved from CAB Abstracts by CABI’s permission

Magnetic Quay water quality and sediment baseline study 1989

A study of water quality and water column sediment loads was carried out in the period mid-December 1988 to mid-February 1989 on the south-east facing fringing reefs of Magnetic Island. The study aimed at providing a baseline before construction commenced on the marina/hotel development planned for the northern end of Nelly Bay. Although it was realized that a complete baseline, allowing for natural seasonal and meteorological variability, could not be produced in two months, as much data as was logistically possible to obtain ·was collected including data from periods of contrasting weather conditions. An associated benthic biota and sedimentation study provided a benthos baseline and measured sediment deposition in sediment traps in the same areas

Biologically mediated weathering in modern cryptogamic ground covers and the early Paleozoic fossil record

Specific micro-weathering features and biochemically derived residues formed by living organisms can be used as biomarkers to infer the presence of biological communities within sedimentary units of ancient ecosystems. We examined basaltic soil minerals from modern cryptogamic ground covers (CGCs) in Iceland and compared these with two early Paleozoic fossil systems. Nine biologically mediated weathering features (BWFs) were identified in modern soils including micron-scale surface trenching and penetrative tunnels, which are attributed to the actions of bacteria, fungi and exudates. Specific BWFs are associated with Fe residues, and with Fe-rich bio-precipitated nodules. Further, putative comparable features and Fe enrichment are identified in palaeosols from the late Silurian (Llansteffan, south Wales) and the Early Devonian (Rhynie chert, Scotland). Although we are cautious about attributing biological affinity to individual isolated features, our results demonstrate the potential of using multiple BWF types as a collective together with their chemical signatures as new proxies to understand community structure and interactions in early terrestrial ecosystems. This new information is the first evidence of interactions between ancient CGC-like organisms and substrate or soil inorganic components in the fossil record, and demonstrates the ability of CGC-like biospheres to contribute to mineral weathering, soil development and biogeochemical cycling during the early Paleozoic. Supplementary material: Fieldwork geomorphological information and triplot SEM-EDS data are available at https://doi.org/10.6084/m9.figshare.c.437371

Gaining, losing, and dry stream reaches at Bear Creek Valley, Oak Ridge, Tennessee, March and September 1994

A study was conducted, to delineate stream reaches that were gaining flow, losing flow, or that were dry in the upper reaches of Bear Creek Valley near the Y-12 Plant in Oak Ridge, Tennessee. The study included a review of maps and discharge data from a seepage investigation conducted at Bear Creek Valley; preparation of tables showing site identification and discharge and stream reaches that were gaining flow, losing flow, or that were dry; and preparation of maps showing measurement site locations and discharge measurements, and gaining, losing, and dry stream reaches. This report will aid in developing a better understanding of ground-water and surface-water interactions in the upper reaches of Bear Creek

MIMO free-space optical communication employing subcarrier intensity modulation in atmospheric turbulence channels

In this paper, we analyse the error performance of transmitter/receiver array free-space optical (FSO) communication system employing binary phase shift keying (BPSK) subcarrier intensity modulation (SIM) in clear but turbulent atmospheric channel. Subcarrier modulation is employed to eliminate the need for adaptive threshold detector. Direct detection is employed at the receiver and each subcarrier is subsequently demodulated coherently. The effect of irradiance fading is mitigated with an array of lasers and photodetectors. The received signals are linearly combined using the optimal maximum ratio combining (MRC), the equal gain combining (EGC) and the selection combining (SelC). The bit error rate (BER) equations are derived considering additive white Gaussian noise and log normal intensity fluctuations. This work is part of the EU COST actions and EU projects

Historical contingency in parasite community assembly: Community divergence results from early host exposure to symbionts and ecological drift

Host individuals are commonly coinfected with multiple parasite species that may interact to shape within-host parasite community structure. In addition to within-host species interactions, parasite communities may also be structured by other processes like dispersal and ecological drift. The timing of dispersal (in particular, the temporal sequence in which parasite species infect a host individual) can alter within-host species interactions, setting the stage for historical contingency by priority effects, but how persistently such effects drive the trajectory of parasite community assembly is unclear, particularly under continued dispersal and ecological drift. We tested the role of species interactions under continued dispersal and ecological drift by simultaneously inoculating individual plants of tall fescue with a factorial combination of three symbionts (two foliar fungal parasites and a mutualistic endophyte), then deploying the plants in the field and tracking parasite communities as they assembled within host individuals. In the field, hosts were exposed to continued dispersal from a common pool of parasites, which should promote convergence in the structure of within-host parasite communities. Yet, analysis of parasite community trajectories found no signal of convergence. Instead, parasite community trajectories generally diverged from each other, and the magnitude of divergence depended on the initial composition of symbionts within each host, indicating historical contingency. Early in assembly, parasite communities also showed evidence of drift, revealing another source of among-host divergence in parasite community structure. Overall, these results show that both historical contingency and ecological drift contributed to divergence in parasite community assembly within hosts. © 2023 Grunberg et al

Continuing professional development:introducing the ERS International Certificate in Respiratory Sleep Medicine

Certification of specialists in respiratory sleep medicine for the purposes of continuing professional developmen

Characterization of a novel Mycoplasma cynos real-time PCR assay

Mycoplasma cynos is recognized as an emerging causative pathogen of canine infectious respiratory disease (CIRD) worldwide. We developed a new open-source real-time PCR (rtPCR) assay for M. cynos that performs well under standard rtPCR conditions. Primers and probes were designed to target the M. cynos tuf gene. Reaction efficiencies for the M. cynos tuf gene assay on 2 platforms were based on amplification of standard curves spanning 8 orders of magnitude: ABI 7500 platform, 94.3-97.9% (r2\u2009 65\u20090.9935); QuantStudio OpenArray platform, 119.1-122.5% (r2 = 0.9784). The assay performed very well over a range of template input, from 109 copies to the lower limit of quantification at 4 copies of the M. cynos genome on the ABI 7500 platform. Diagnostic performance was estimated by comparison with an in-house legacy assay on clinical specimens as well as testing isolates that were characterized previously by intergenic spacer region (ISR) sequencing. Exclusivity was established by testing 12 other Mycoplasma species. To substantiate the high specificity of the M. cynos tuf gene assay, sequence confirmation was performed on ISR PCR amplicons obtained from clinical specimens. One ISR amplicon sequence revealed M. mucosicanis rather than M. cynos. The complete protocol of the newly developed M. cynos tuf assay is provided to facilitate assay harmonization

Exchange coupling in CaMnO3_3 and LaMnO3_3: configuration interaction and the coupling mechanism

The equilibrium structure and exchange constants of CaMnO$_3$ and LaMnO$_3$ have been investigated using total energy unrestricted Hartree-Fock (UHF) and localised orbital configuration interaction (CI) calculations on the bulk compounds and Mn$_2$O$_{11}^{14-}$ and Mn$_2$O$_{11}^{16-}$ clusters. The predicted structure and exchange constants for CaMnO$_3$ are in reasonable agreement with estimates based on its N\'eel temperature. A series of calculations on LaMnO$_3$ in the cubic perovskite structure shows that a Hamiltonian with independent orbital ordering and exchange terms accounts for the total energies of cubic LaMnO$_3$ with various spin and orbital orderings. Computed exchange constants depend on orbital ordering. UHF calculations tend to underestimate exchange constants in LaMnO$_3$, but have the correct sign when compared with values obtained by neutron scattering; exchange constants obtained from CI calculations are in good agreement with neutron scattering data provided the Madelung potential of the cluster is appropriate. Cluster CI calculations reveal a strong dependence of exchange constants on Mn d e$_g$ orbital populations in both compounds. CI wave functions are analysed in order to determine which exchange processes are important in exchange coupling in CaMnO$_3$ and LaMnO$_3$.Comment: 25 pages and 9 postscript figure