Exhaust Nozzles for Supersonic Flight with Turbojet Engines

Good internal performance over a wide range of flight conditions can be obtained with either a plug nozzle or a variable ejector nozzle that can provide a divergent shroud at high pressure ratios. For both the ejector and the plug nozzle, external flow can sometimes cause serious drag losses and, for some plug-nozzle installations, external flow can cause serious internal performance losses. Plug-nozzle cooling and design of the secondary-air-flow systems for ejectors were also considered

A Graphic Method For Depicting Horizontal Direction Data On Vertical Outcrop Photographs

Outcrop photographs which show two-dimensional representations of three-dimensionally dipping surfaces (e.g., bedding planes, cross-bed foresets) are commonly utilized in the description of sedimentary strata. In many instances, accurate depiction of the dip direction of such features is paramount for understanding their interpretation, and for visualizing the true form of three-dimensional bodies (e.g., conceptualizing the form of an architectural element in a cliff-face, preserved as a vertical slice that has been cut oblique to paleocurrent direction). However, as an outcrop photograph often presents information on a vertical plane and directional data refers to a horizontal plane, the accurate co-depiction of both sets of information may be challenging. There is presently no universal method for illustrating such measurements on outcrop photographs: techniques in common usage are often imprecise, and the lack of uniformity hinders comparison between different images. Here we present a method for accurately depicting horizontal direction data on vertical outcrop photographs which permits instant visualization of dip relative to the illustrated outcrop geometry. The method is simple to apply, does not compromise primary data, and is unobtrusive to other visual information within images; thus having utility across a broad spectrum of geological investigations

Short-term evolution of primary sedimentary surface textures (microbial, abiotic, ichnological) on a dry stream bed: modern observations and ancient implications

A wide variety of sub-ripple-scale sedimentary surface textures are known from bedding planes in the sedimentary rock record. Many of these textures were traditionally ascribed an abiotic origin (e.g., due to rain drop impact, adhesion, etc.), but in recent decades the role of microbial mats and biofilms in sculpting and mediating some forms has become increasingly recognized. Microbial sedimentary textures are now well-described and understood from modern tidal environments and biological soil crusts, but descriptions from fluvial settings are less common, despite their known occurrence in ancient alluvium. This paper reports a suite of primary sedimentary surface textures which were observed forming in discrete bodies of standing water in the lower reaches of the ephemeral Murchison River, Western Australia. Microbial sedimentary signatures included bubble impressions (burst and intact) and roll-ups, in addition to reduced horizons. Many of these features exhibited rapid temporal evolution of their morphology in the dry days following an interval of heavy rain. Significantly, these microbial features were witnessed in close spatial proximity to other abiotic and biotic sedimentary surface textures including raindrop impressions, adhesion marks, desiccation cracks, and vertebrate and invertebrate traces. Such proximity of abiotic and microbial sedimentary surface textures is rarely reported from bedding planes in the rock record, but these modern observations emphasize the fact that, particularly in non-marine environments, such structures should not be expected to be mutually exclusive. An appreciation of the fact that primary sedimentary surface textures such as these develop during intervals of stasis in a sedimentation system is crucial to our understanding of their significance and diversity in the rock record

Dinosaur-landscape interactions at a diverse Early Cretaceous tracksite (Lee Ness Sandstone, Ashdown Formation, southern England)

An assemblage of dinosaur footprints is reported from the Lower Cretaceous (Berriasian-Valanginian) Ashdown Formation of East Sussex, southern England. The ichnofauna is concentrated around a 2 m thick stratigraphic marker, the Lee Ness Sandstone, where recent cliff retreat has revealed 85 recognisable footprints attributable to 13 morphotypes, many of which bear high-fidelity skin impressions. The newly identified morphotypes mean that this tracksite hosts one of the most diverse dinosaur ichnoassemblages in the well-documented Mesozoic record of Britain; recording the activity of theropod, ornithopod, thyreophoran and possibly sauropod tracemakers. Most of the footprints were emplaced on a single floodplain mudstone horizon beneath a fluvial crevasse splay sandstone, where preservation was favoured by cohesive sediment and a prolonged interval of sedimentary stasis, during which trackways could be imparted. The sedimentological context of the trackways reveals evidence of interactions between dinosaurs and the riverine landscape that they inhabited; including the development of microtopographies around footprints, which impacted invertebrate burrowing activity, and evidence for dinosaur wading below the bankfull level of small meandering channels and oxbow lakes. Modern analogue suggests that the large dinosaurs may have played a significant role as zoogeomorphic engineers within the ancient floodplain setting, but the imperfect translation of sedimentary environment to sedimentary rock means that geological evidence for such is ambiguous

Death near the Shoreline, not Life on Land: Ordovician Arthropod Trackways in the Borrowdale Volcanic Group, UK

The Borrowdale Volcanic Group of northern England hosts Late Ordovician arthropod trackways that are frequently cited as the earliest unequivocal evidence for animal life on land, and provides a key geological locality for our understanding of myriapod evolution and terrestrialization. Original fieldwork at the site has identified four additional bedding surfaces that yield 121 new trackways (of a total 158 known individuals), permitting better sedimentological and paleoecological contextualization of the trackways. Contrary to published claims, none of the trackways occur in sandstones but are invariably preserved on dacitic tuff bedding planes. Trackway morphology comprises either short straight segments with discernable footprint impressions (Diplichnites), long looping traces suggesting dragging and footprint amalgamation (Diplopodichnus), or transitional forms. Morphometric comparison of the Diplopodichnus with fossil and recent mortichnia (death traces) suggests they record immediate pre-mortem locomotion of dying myriapods, and modern analogue reveals mechanisms by which abundant volcanic ash would have elevated arthropod mortality rates. Sedimentary structures including wave ripples, bedding sags and detached large- scale ball-and-pillow structures, show that the tuffs were deposited subaqueously. One instance where trackways intermittently traverse 3-5 cm tracts of subaerially-exposed wave-ripple crestlines attests that the tracemakers were capable of surviving out of water over limited distances. The low diversity ichnofauna has greater similarity with other Cambrian and Ordovician sites, recording semi-subaqueous pioneer tracemakers, than it does with the earliest fully-terrestrial ichnofaunas from the Silurian and Devonian

Cold Feet: trackways and burrows in ice-marginal strata of the end-Ordovician glaciation (Table Mountain Group, South Africa)

New observations from an outcrop of Upper Ordovician Table Mountain Group strata (Matjiesgoedkloof, Western Cape Province, South Africa) have revealed an unexpected ichnofauna, hosted within diamictites and sandstones that were deposited by a retreating low-latitude (c. 30{degree sign}S) ice sheet during the Hirnantian glaciation. The locality provides a rare window onto animal-sediment interactions in an early Paleozoic ice-marginal shallow marine environment and contains a trace fossil community with a surprising ichnodiversity and ichnodisparity of burrows, trackways and trails (Archaeonassa, Diplichnites, Heimdallia, Metaichna, ?Multina, Planolites, Protovirgularia, Skolithos). Exceptional phenomena preserved in the strata include evidence for direct colonization of glacial diamictites by deep-burrowing Heimdallia infauna, and interactions between trackways and dropstones on substrates. Observations from the newly-recognized outcrop dramatically expand our understanding of deep time glacial habitats, demonstrating that deglaciating ice-margins had already been colonized by the latest Ordovician. The freshwater influx that would have been associated with such settings implies that faunal associations which were tolerant of brackish water were also established by that time. The locality has further significance because it records the activity of a nearshore animal community contemporaneous with the fauna of the nearby Soom Shale lägerstatte. Combined, these reveal a paleoecological transect of the diverse marine life that inhabited cold-climate, low-latitude shallow seas around the time of the end-Ordovician deglaciation

Life in a warm deep sea: routine activity and burst swimming performance of the shrimp Acanthephyra eximia in the abyssal Mediterranean

Measurements of routine swimming speed, "tail-flip'' escape responses, and oxygen consumptions were made of the deep-sea shrimp Acanthephyra eximia using autonomous landers in the Rhodos Basin at depths of up to 4,400 m and temperatures of 13 - 14.5 degrees C. Routine swimming speeds at 4,200 m averaged 0.18 m s(-1) or 3.09 body lengths s(-1), approximately double those of functionally similar oceanic scavengers. During escape responses peak accelerations of 23 m s(-2) or 630.6 body lengths s(-2) were recorded, with animals reaching speeds of 1.61 m s(-1) or 34.8 body lengths s(-2). When compared to shallow-water decapods at similar temperatures these values are low for a lightly calcified shrimp such as A. eximia despite a maximum muscle mass specific power output of 90.0 W kg(-1). A preliminary oxygen consumption measurement indicated similar rates to those of oceanic crustacean scavengers and shallower-living Mediterranean crustaceans once size and temperature had been taken into account. These animals appear to have high routine swimming speeds but low burst muscle performances. This suite of traits can be accounted for by high competition for limited resources in the eastern Mediterranean, but low selective pressure for burst swimming due to reductions in predator pressure

Barriers and facilitators experienced by osteopaths in implementing a biopsychosocial (BPS) framework of care when managing people with musculoskeletal pain – A mixed methods systematic review protocol

Background: Musculoskeletal (MSK) pain conditions have a substantial influence on the quality of life. Psychosocial factors such as depression, anxiety and social isolation have been shown to play an important role in the development and management of MSK pain. Therefore, clinical practice guidelines commonly recommend adopting a biopsychosocial (BPS) framework by practitioners managing MSK pain. However, it remains unclear how osteopaths implement a BPS framework in the management of MSK pain. This protocol describes the objective and methods of a systematic review of barriers and facilitators experienced by osteopaths in implementing a BPS framework of care when managing people with MSK pain. Methods: The following electronic databases from January 2005 to March 2019 will be searched: PubMed, AMED, EMBASE, CINAHL, Cochrane Library, Physiotherapy Evidence Database (PEDro), and SCOPUS. Two independent reviewers will review the title, abstract and full-text article retrieved from the databases to assess potentially eligible studies. Any studies (quantitative, qualitative and mixed methods) that investigated the use or application of the biopsychosocial approach in osteopathic practice will be included in the review. Data synthesis for qualitative studies will be done using the GRADE‐CERQual tool. Data synthesis methods for mixed method studies will be decided after data extraction and assessment. Discussion: This systematic review will provide critical insights into the barriers and facilitators experienced by osteopaths to implement the BPS framework in their practice. This may be important and timely as a BPS framework has been recommended by various clinical practice guidelines. © 2020 Elsevier Lt

Tomato protoplast DNA transformation: physical linkage and recombination of exogenous DNA sequences

Tomato protoplasts have been transformed with plasmid DNA's, containing a chimeric kanamycin resistance gene and putative tomato origins of replication. A calcium phosphate-DNA mediated transformation procedure was employed in combination with either polyethylene glycol or polyvinyl alcohol. There were no indications that the tomato DNA inserts conferred autonomous replication on the plasmids. Instead, Southern blot hybridization analysis of seven kanamycin resistant calli revealed the presence of at least one kanamycin resistance locus per transformant integrated in the tomato nuclear DNA. Generally one to three truncated plasmid copies were found integrated into the tomato nuclear DNA, often physically linked to each other. For one transformant we have been able to use the bacterial ampicillin resistance marker of the vector plasmid pUC9 to 'rescue' a recombinant plasmid from the tomato genome. Analysis of the foreign sequences included in the rescued plasmid showed that integration had occurred in a non-repetitive DNA region. Calf-thymus DNA, used as a carrier in transformation procedure, was found to be covalently linked to plasmid DNA sequences in the genomic DNA of one transformant. A model is presented describing the fate of exogenously added DNA during the transformation of a plant cell. The results are discussed in reference to the possibility of isolating DNA sequences responsible for autonomous replication in tomato.