24,641 research outputs found
Cranial sutures work collectively to distribute strain throughout the reptile skull
The skull is composed of many bones that come together at sutures. These sutures are important sites of growth, and as growth ceases some become fused while others remain patent. Their mechanical behaviour and how they interact with changing form and loadings to ensure balanced craniofacial development is still poorly understood. Early suture fusion often leads to disfiguring syndromes, thus is it imperative that we understand the function of sutures more clearly. By applying advanced engineering modelling techniques, we reveal for the first time that patent sutures generate a more widely distributed, high level of strain throughout the reptile skull. Without patent sutures, large regions of the skull are only subjected to infrequent low-level strains that could weaken the bone and result in abnormal development. Sutures are therefore not only sites of bone growth, but could also be essential for the modulation of strains necessary for normal growth and development in reptiles
A study and experiment plan for digital mobile communication via satellite
The viability of mobile communications is examined within the context of a frequency division multiple access, single channel per carrier satellite system emphasizing digital techniques to serve a large population of users. The intent is to provide the mobile users with a grade of service consistant with the requirements for remote, rural (perhaps emergency) voice communications, but which approaches toll quality speech. A traffic model is derived on which to base the determination of the required maximum number of satellite channels to provide the anticipated level of service. Various voice digitalization and digital modulation schemes are reviewed along with a general link analysis of the mobile system. Demand assignment multiple access considerations and analysis tradeoffs are presented. Finally, a completed configuration is described
The biomechanical role of the chondrocranium and sutures in a lizard cranium
The role of soft tissues in skull biomechanics remains poorly understood. Not least, the chondrocranium, the portion of the braincase which persists as cartilage with varying degrees of mineralization. It also remains commonplace to overlook the biomechanical role of sutures despite evidence that they alter strain distribution. Here, we examine the role of both the sutures and the chondrocranium in the South American tegu lizard Salvator merianae. We use multi-body dynamics analysis (MDA) to provide realistic loading conditions for anterior and posterior unilateral biting and a detailed finite element model to examine strain magnitude and distribution. We find that strains within the chondrocraniumare greatest during anterior biting and are primarily tensile; also that strain within the cranium is not greatly reduced by the presence of the chondrocraniumunless it is given the same material properties as bone. This result contradicts previous suggestions that the anterior portion (the nasal septum) acts as a supporting structure. Inclusion of sutures to the cranium model not only increases overall strain magnitudes but also leads to a more complex distribution of tension and compression rather than that of a beam under sagittal bending
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Replication enhancer elements within the open reading frame of tick-borne encephalitis virus and their evolution within the Flavivirus genus
We provide experimental evidence of a replication enhancer element (REE) within the capsid gene of tick-borne encephalitis virus (TBEV, genus Flavivirus). Thermodynamic and phylogenetic analyses predicted that the REE folds as a long stable stem–loop (designated SL6), conserved among all tick-borne flaviviruses (TBFV). Homologous sequences and potential base pairing were found in the corresponding regions of mosquito-borne flaviviruses, but not in more genetically distant flaviviruses. To investigate the role
of SL6, nucleotide substitutions were introduced which changed a conserved hexanucleotide motif, the conformation of the terminal loop and the base-paired dsRNA stacking. Substitutions were made within a TBEV reverse genetic system and recovered mutants were compared for plaque
morphology, single-step replication kinetics and cytopathic effect. The greatest phenotypic changes were observed in mutants with a destabilized stem. Point mutations in the conserved hexanucleotide motif of the terminal loop caused
moderate virus attenuation. However, all mutants
eventually reached the titre of wild-type virus late post-infection. Thus, although not essential for growth in tissue culture, the SL6 REE acts to up-regulate virus replication. We hypothesize that this modulatory role may be important for TBEV survival in nature, where the virus circulates by non-viraemic transmission between infected and
non-infected ticks, during co-feeding on local rodents
Young adults' experiences of dialysis or kidney transplant decision-making
Young adults with kidney failure experience disruptions in their education, growth development, building relationships and face employment problems during the journey of the disease (Murray et al., 2014). Once their kidneys fail, they need to make a choice about which dialysis treatment to have or whether they prefer the option of kidney transplant.
So, they have to work with their health care professionals to make decisions to select their preferred dialysis or kidney transplant choice. This is known as shared decision-making.
The three-talk model of shared decision making shown on the screen is used as a guide by health care professionals to encourage discussions of treatment options with patients during the shared decision-making process (Elwyn et al., 2018).
A recent report by the renal registry highlighted that over 50% of young adults with kidney failure started haemodialysis as their first treatment option and less of them (14.1%) received a kidney transplant, although kidney transplantation is recommended as the best treatment (NICE, 2014).
Evidence suggests that among adults with kidney failure, not all patients receive timely information on kidney failure treatment options to enable them share in the decision-making or make an informed choice, which falls short of the recommended guidelines.
It matters because little is known about young adults with kidney failure experiences of dialysis or kidney transplant decision-making and how the decision to select a dialysis or kidney transplant choice may have impacted on their psychosocial and mental well-being.
This is where my study plays an important role. Our involvement group who have dialysis and kidney transplant experiences as children and young adults, suggested that the study should focus on the impact of decision-making on the psychosocial and mental well-being of young adults as it was a neglected area and their views incorporated.
My study will explore young adults’ experiences of decision-making to select a dialysis or kidney transplant choice. It will examine the impact of dialysis or kidney transplant decision-making on young adults psychosocial and mental well-being. Lastly it will seek to understand how young adults can be better supported during the decision-making process to enhance their coping abilities and participation in the decision-making process
Matter Wave Scattering and Guiding by Atomic Arrays
We investigate the possibility that linear arrays of atoms can guide matter
waves, much as fiber optics guide light. We model the atomic line as a quasi-1D
array of s wave point scatterers embedded in 2D. Our theoretical study reveals
how matter wave guiding arises from the interplay of scattering phenomena with
bands and conduction along the array. We discuss the conditions under which a
straight or curved array of atoms can guide a beam focused at one end of the
array.Comment: Submitted to Phys. Rev.
Populations of OB-type stars in galaxies
One of the challenges for stellar astrophysics is to reach the point at which
we can undertake reliable spectral synthesis of unresolved populations in
young, star-forming galaxies at high redshift. Here I summarise recent studies
of massive stars in the Galaxy and Magellanic Clouds, which span a range of
metallicities commensurate with those in high-redshift systems, thus providing
an excellent laboratory in which to study the role of environment on stellar
evolution. I also give an overview of observations of luminous supergiants in
external galaxies out to a remarkable 6.7 Mpc, in which we can exploit our
understanding of stellar evolution to study the chemistry and dynamics of the
host systems.Comment: 9 pages, 3 figures, invited review at IAU Symposium 272 (eds Neiner,
Wade, Meynet & Peters
Rescue Geography: research exhibition and photographic installation:24-31 October, MADE, Fazeley Street, Digbeth
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