Cold-water coral reef frameworks, megafaunal communities and evidence for coral carbonate mounds on the Hatton Bank, north east Atlantic

Offshore banks and seamounts sustain diverse megafaunal communities, including framework reefs formed by cold-water corals. Few studies have quantified environmental effects on the alpha or beta diversity of these communities. We adopted an interdisciplinary approach that used historical geophysical data to identify topographic highs on Hatton Bank, which were surveyed visually. The resulting photographic data were used to examine relationships between megafaunal communities and macrohabitat, the latter defined into six categories (mud, sand, cobbles, coral rubble, coral framework, rock). The survey stations revealed considerable small-scale variability in macrohabitat from exposed Late Palaeocene lava flows to quiescent muddy habitats and coral-built carbonate mounds. The first reported evidence for coral carbonate mound development in UK waters is presented, which was most pronounced near present-day or former sites of topographic change, suggesting that local current acceleration favoured coral framework growth and mound initiation. Alpha diversity varied significantly across macrohabitats, but not between rock and coral rubble, or between smaller grain sized categories of cobbles, sand and mud. Community composition differed between most macrohabitats, and variation in beta diversity across Hatton Bank was largely explained by fine-scale substratum. Certain megafauna were clearly associated with particular macrohabitats, with stylasterid corals notably associated with cobble and rock habitats and coral habitats characterized by a diverse community of suspension-feeders. The visual surveys also produced novel images of deep-water megafauna including a new photographic record of the gorgonian coral Paragorgia arborea, a species not previously reported from Rockall Plateau. Further interdisciplinary studies are needed to interpret beta diversity across these and other environmental gradients on Hatton Bank. It is clear that efforts are also needed to improve our understanding of the genetic connectivity and biogeography of vulnerable deep-water ecosystems and to develop predictive models of their occurrence that can help inform future conservation measures

Identification of the C2-1H histidine NMR resonances in chloramphenicol acetyltransferase by a 13C-1H heteronuclear multiple quantum coherence method

AbstractChloramphenicol acetyltransferase (CAT) was used to assess the feasibility of study of specific proton resonances in an enzyme of overall molecular mass 75000. [ring2-13C]Histidine was selectively incorporated into the type III chloramphenicol acetyltransferase (CATIII) using a histidine auxotroph of E. coli. Heteronuclear multiple and single quantum experiments were used to select the C2 protons in the histidyl imidazole ring. One- and two-dimensional spectra revealed six signals out of a total of seven histidine residues in CATIII. pH titration, chemical modification and ligand binding were used to demonstrate that the signal from H195, the histidine at the active site, is not among those observed. Nevertheless, this work demonstrates that selective isotopic enrichment and multiple quantum coherence techniques can be used to distinguish proton resonances in a protein of high molecular mass

Biophysical Analysis of Nucleic Acids

This overview unit provides a thorough overview of biophysical methods used for structure analysis, including X‐ray diffraction, nuclear magnetic resonance, optical spectroscopy, theoretical and computational methods, and single‐molecule methods. Advantages and disadvantages of the methods are compared.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143731/1/cpnc0701.pd

Occurrence of partial and total coseismic ruptures of segmented normal fault systems: insights from the Central Apennines, Italy

Normal faulting earthquakes rarely rupture the entire extent of active normal faults, and can also jump between neighbouring faults. This confounds attempts to use segmentation models to define the likelihood of future rupture scenarios. We attempt to study this problem comparing the offsets produced in single earthquakes with those produced by multiple earthquakes over longer timescales, together with detailed studies of the structural geology. We study the active normal fault system causative of the Mw 6.3 2009 L’Aquila earthquake in central Italy, comparing the spatial distribution of coseismic offsets, cumulative offsets that have developed since 15 ±3 ka, and the total offsets that have accumulated since the faults initiated at 2-3 Ma. Our findings suggest that: 1) faults within a segmented fault system behave as a single interacting fault segment over time periods including multiple earthquake cycles (e.g. 2-3 Ma or 15±3ka), with single earthquakes causing either partial or total ruptures of the entire system; 2) an along-strike bend causes throw and throw-rates enhancements within the bend throughout the seismic history of the fault system. We discuss the synchronised and geometrically controlled activity rates on these faults in terms of the propensity for floating earthquakes, multi-fault earthquakes, and seismic hazard

Zero Temperature Limit of Holographic Superconductors

We consider holographic superconductors whose bulk description consists of gravity minimally coupled to a Maxwell field and charged scalar field with general potential. We give an analytic argument that there is no "hard gap": the real part of the conductivity at low frequency remains nonzero (although typically exponentially small) even at zero temperature. We also numerically construct the gravitational dual of the ground state of some holographic superconductors. Depending on the charge and dimension of the condensate, the infrared theory can have emergent conformal or just Poincare symmetry. In all cases studied, the area of the horizon of the dual black hole goes to zero in the extremal limit, consistent with a nondegenerate ground state.Comment: 27 pages, 8 figure

Active normal faulting during the 1997 seismic sequence in Colfiorito, Umbria: Did slip propagate to the surface?

In order to determine whether slip during an earthquake on the 26th September 1997 propagated to the surface, structural data have been collected along a bedrock fault scarp in Umbria, Italy. These collected data are used to investigate the relationship between the throw associated with a debated surface rupture (observed as a pale unweathered stripe at the base of the bedrock fault scarp) and the strike, dip and slip-vector. Previous studies have suggested that the surface rupture was produced either by primary surface slip or secondary compaction of hangingwall sediments. Some authors favour the latter because sparse surface fault dip measurements do not match nodal plane dips at depth. It is demonstrated herein that the strike, dip and height of the surface rupture, represented by a pale unweathered stripe at the base of the bedrock scarp, shows a systematic relationship with respect to the geometry and kinematics of faulting in the bedrock. The strike and dip co-vary and the throw is greatest where the strike is oblique to the slip-vector azimuth where the highest dip values are recorded. This implies that the throw values vary to accommodate spatial variation in the strike and dip of the fault across fault plane corrugations, a feature that is predicted by theory describing conservation of strain along faults, but not by compaction. Furthermore, published earthquake locations and reported fault dips are consistent with the analysed surface scarps when natural variation for surface dips and uncertainty for nodal plane dips at depth are taken into account. This implies that the fresh stripe is indeed a primary coseismic surface rupture whose slip is connected to the seismogenic fault at depth. We discuss how this knowledge of the locations and geometry of the active faults can be used as an input for seismic hazard assessment

Investigating linkage rates among probabilistically linked birth and hospitalization records

BACKGROUND: With the increasing use of probabilistically linked administrative data in health research, it is important to understand whether systematic differences occur between the populations with linked and unlinked records. While probabilistic linkage involves combining records for individuals, population perinatal health research requires a combination of information from both the mother and her infant(s). The aims of this study were to (i) describe probabilistic linkage for perinatal records in New South Wales (NSW) Australia, (ii) determine linkage proportions for these perinatal records, and (iii) assess records with linked mother and infant hospital-birth record, and unlinked records for systematic differences. METHODS: This is a population-based study of probabilistically linked statutory birth and hospital records from New South Wales, Australia, 2001-2008. Linkage groups were created where the birth record had complete linkage with hospital admission records for both the mother and infant(s), partial linkage (the mother only or the infant(s) only) or neither. Unlinked hospital records for mothers and infants were also examined. Rates of linkage as a percentage of birth records and descriptive statistics for maternal and infant characteristics by linkage groups were determined. RESULTS: Complete linkage (mother hospital record – birth record – infant hospital record) was available for 95.9% of birth records, partial linkage for 3.6%, and 0.5% with no linked hospital records (unlinked). Among live born singletons (complete linkage = 96.5%) the mothers without linked infant records (1.6%) had slightly higher proportions of young, non-Australian born, socially disadvantaged women with adverse pregnancy outcomes. The unlinked birth records (0.4%) had slightly higher proportions of nulliparous, older, Australian born women giving birth in private hospitals by caesarean section. Stillbirths had the highest rate of unlinked records (3-4%). CONCLUSIONS: This study shows that probabilistic linkage of perinatal records can achieve high, representative levels of complete linkage. Records for mother’s that did not link to infant records and unlinked records had slightly different characteristics to fully linked records. However, these groups were small and unlikely to bias results and conclusions in a substantive way. Stillbirths present additional challenges to the linkage process due to lower rates of linkage for lower gestational ages, where most stillbirths occur

A European Pharmaceutical Aerosol Group (EPAG)-led cross-industry assessment of inlet flow rate profiles of compendial DPI test systems: Part 1 – experimental data

We report outcomes from an EPAG-led cross-industry study, characterizing flow rate/elapsed-time profiles of equipment used for testing dry powder inhalers (DPIs). A thermal mass flow sensor was used by nine organizations in a round-robin approach to record inlet flow rate-time profiles of individual participant compendial test systems (TS) including either sample collection tubes (SCT) or a cascade impactor (either the Andersen 8-stage non-viable impactor, ACI, or the Next Generation Impactor, NGI) equipped with USP/PhEur induction port and pre-separator. An inlet orifice generated a 4-kPa pressure drop at each of the target flow rates (30, 60 and 90 L/min), simulating a pressure drop typical for high-, medium- and low-resistance DPIs respectively. Rise times to 90% of these target flow rates (t90) were longest with largest internal dead volume and followed the order NGI>ACI >SCT>TS. When the surrogate DPI (4-kPa orifice) was absent, t90 values generally lengthened with increasing target flow rate. In contrast, the opposite behaviour was observed when the surrogate DPI was present. A flow acceleration parameter was also calculated, expressed as the slope between the 20% and 80% flow rates of each final steady flow value (slopet20/t80). Greater flow acceleration occurred at higher final flow rates, irrespective of apparatus, but the presence of the surrogate DPI was associated with slower flow acceleration. These flow rate-rise time profiles will be useful for those involved in evaluating equipment for characterizing both existing and new DPIs