Design of passive vehicle suspensions for maximal least damping ratio

This paper studies the use of the least damping ratio among system poles as a performance metric in passive vehicle suspensions. Methods are developed which allow optimal solutions to be computed in terms of non-dimensional quantities in a quarter-car vehicle model. Solutions are provided in graphical form for convenient use across vehicle types. Three suspension arrangements are studied: the standard suspension involving a parallel spring and damper and two further suspension arrangements involving an inerter. The key parameters for the optimal solutions are the ratios of unsprung mass to sprung mass and suspension static stiffness to tyre vertical stiffness. A discussion is provided of performance trends in terms of the key parameters. A comparison is made with the optimisation of ride comfort and tyre grip metrics for various vehicle types.This work was supported by the Engineering and Physical Sciences Research Council grant numbers EP/F062656/1 and EP/G066477/1.This is the final version of the article. It first appeared from Taylor & Francis via https://doi.org/10.1080/00423114.2016.114524

Lattice Boltzmann Equation: Failure or Success?

The lattice Boltzmann equation (LBE) is a microscopically-inspired method designed to solve macroscopic fluid dynamics problems. As a such, it lives at the interface between the microscopic (molecular) and macroscopic (continuum) worlds, hopefully capturing the best of the two. In this paper we shall discuss whether or not, after almost a decade since its inception, LBE has lived up to the initial expectations. Open problems and future research developments are also briefly outlined

Distance determination to 12 Type II-P Supernovae using the Expanding Photosphere Method

We use early-time photometry and spectroscopy of 12 Type II plateau supernovae (SNe IIP) to derive their distances using the expanding photosphere method (EPM). We perform this study using two sets of Type II supernova (SN II) atmosphere models, three filter subsets ($\{BV\}$, $\{BVI\}$, $\{VI\}$), and two methods for the host-galaxy extinction, which leads to 12 Hubble diagrams. We find that systematic differences in the atmosphere models lead to $\sim$50% differences in the EPM distances and to a value of ${\rm H_0}$ between 52 and 101 ${\rm km s^{-1} Mpc^{-1}}$. Using the $\{VI\}$ filter subset we obtain the lowest dispersion in the Hubble diagram, {${\rm \sigma_{\mu} = 0.32}$ mag}. We also apply the EPM analysis to the well-observed SN IIP 1999em. With the $\{VI\}$ filter subset we derive a distance ranging from 9.3 $\pm$ 0.5 Mpc to 13.9 $\pm$ 1.4 Mpc depending on the atmosphere model employed.Comment: Accepted for publication in the Astrophysical Journa

A second transmissible cancer in Tasmanian devils.

Clonally transmissible cancers are somatic cell lineages that are spread between individuals via the transfer of living cancer cells. There are only three known naturally occurring transmissible cancers, and these affect dogs, soft-shell clams, and Tasmanian devils, respectively. The Tasmanian devil transmissible facial cancer was first observed in 1996, and is threatening its host species with extinction. Until now, this disease has been consistently associated with a single aneuploid cancer cell lineage that we refer to as DFT1. Here we describe a second transmissible cancer, DFT2, in five devils located in southern Tasmania in 2014 and 2015. DFT2 causes facial tumors that are grossly indistinguishable but histologically distinct from those caused by DFT1. DFT2 bears no detectable cytogenetic similarity to DFT1 and carries a Y chromosome, which contrasts with the female origin of DFT1. DFT2 shows different alleles to both its hosts and DFT1 at microsatellite, structural variant, and major histocompatibility complex (MHC) loci, confirming that it is a second cancer that can be transmitted between devils as an allogeneic, MHC-discordant graft. These findings indicate that Tasmanian devils have spawned at least two distinct transmissible cancer lineages and suggest that transmissible cancers may arise more frequently in nature than previously considered. The discovery of DFT2 presents important challenges for the conservation of Tasmanian devils and raises the possibility that this species is particularly prone to the emergence of transmissible cancers. More generally, our findings highlight the potential for cancer cells to depart from their hosts and become dangerous transmissible pathogens.We thank Bill Brown, Phil Iles, Billie Lazenby, Jacinta Marr, Jane McGee, Sarah Peck, Holly Wiersma and Phil Wise for assistance with sample collection and curation. Adrian Baez-Ortega, Andrew Davis, Jo Hanuszewicz, Gina Kalodimos, Amanda Patchett, Narelle Phillips, Elizabeth Reid Swainscoat, Jim Richley, Rachel Stivicic and Jim Taylor assisted with surveying, laboratory analysis, data processing and display. We are grateful for support received from Mike Stratton, the Wellcome Trust Sanger Institute (WTSI) sequencing and informatics teams and the WTSI Cancer Genome Project. This work was supported by a Wellcome Trust Investigator Award (102942/Z/13/Z) and by grants from the Australian Research Council (ARC-DP130100715; ARC-LP130100218). Support was provided by Dr Eric Guiler Tasmanian Devil Research Grants and by the Save the Tasmanian Devil Program. JMCT was partly supported by a Marie Curie Fellowship (FP7-PEOPLE- 2012-IEF, 328364). Sequences associated with this paper have been deposited in Genbank with accession numbers KT188437 and KT188438

Acute Renal Failure in Association with Community-Acquired Clostridium difficile Infection and McKittrick-Wheelock Syndrome

We report the case of a 65-year-old Caucasian woman who experienced two separate episodes of acute renal failure within an 18-month period, both requiring emergency admission and complicated treatment. Each episode was precipitated by hypovolaemia from intestinal fluid losses, but from two rare and independent pathologies. Her first admission was attributed to community-acquired Clostridium difficile-associated diarrhoea (CDAD) and was treated in the intensive therapy unit. She returned 18 months later with volume depletion and electrolyte disturbances, but on this occasion a giant hypersecretory villous adenoma of the rectum (McKittrick-Wheelock syndrome) was diagnosed following initial abnormal findings on digital rectal examination by a junior physician. Unlike hospital-acquired C. difficile, community-acquired infection is not common, although increasing numbers are being reported. Whilst community-acquired CDAD can be severe, it rarely causes acute renal failure. This case report highlights the pathological mechanisms whereby C. difficile toxin and hypersecretory villous adenoma of the rectum can predispose to acute renal failure, as well as the values of thorough clinical examination in the emergency room, and early communication with intensivist colleagues in dire situations

Coordinated optimization of visual cortical maps (I) Symmetry-based analysis

In the primary visual cortex of primates and carnivores, functional architecture can be characterized by maps of various stimulus features such as orientation preference (OP), ocular dominance (OD), and spatial frequency. It is a long-standing question in theoretical neuroscience whether the observed maps should be interpreted as optima of a specific energy functional that summarizes the design principles of cortical functional architecture. A rigorous evaluation of this optimization hypothesis is particularly demanded by recent evidence that the functional architecture of OP columns precisely follows species invariant quantitative laws. Because it would be desirable to infer the form of such an optimization principle from the biological data, the optimization approach to explain cortical functional architecture raises the following questions: i) What are the genuine ground states of candidate energy functionals and how can they be calculated with precision and rigor? ii) How do differences in candidate optimization principles impact on the predicted map structure and conversely what can be learned about an hypothetical underlying optimization principle from observations on map structure? iii) Is there a way to analyze the coordinated organization of cortical maps predicted by optimization principles in general? To answer these questions we developed a general dynamical systems approach to the combined optimization of visual cortical maps of OP and another scalar feature such as OD or spatial frequency preference.Comment: 90 pages, 16 figure

Managing soil fertility in organic farming systems

Complex relationships exist between different components of the organic farm and the quantity and quality of the end products depend on the functioning of the whole system. As such, it is very difficult to isolate soil fertility from production and environmental aspects of the system. Crop rotation is the central tool that integrates the maintenance and development of soil fertility with different aspects of crop and livestock production in organic systems. Nutrient supply to crops depends on the use of legumes to add nitrogen to the system and limited inputs of supplementary nutrients, added in acceptable forms. Manures and crop residues are carefully managed to recycle nutrients around the farm. Management of soil organic matter, primarily through the use of short-term leys, helps ensure good soil structure and biological activity, important for nutrient supply, health and productivity of both crops and livestock. Carefully planned diverse rotations help reduce the incidence of pests and diseases and allow for cultural methods of weed control. As a result of the complex interactions between different system components, fertility management in organic farming relies on a long-term integrated approach rather than the more short-term very targeted solutions common in conventional agriculture

No evidence for association of ataxia-telangiectasia mutated gene T2119C and C3161G amino acid substitution variants with risk of breast cancer

BACKGROUND: There is evidence that certain mutations in the double-strand break repair pathway ataxia-telangiectasia mutated gene act in a dominant-negative manner to increase the risk of breast cancer. There are also some reports to suggest that the amino acid substitution variants T2119C Ser707Pro and C3161G Pro1054Arg may be associated with breast cancer risk. We investigate the breast cancer risk associated with these two nonconservative amino acid substitution variants using a large Australian population-based case–control study. METHODS: The polymorphisms were genotyped in more than 1300 cases and 600 controls using 5' exonuclease assays. Case–control analyses and genotype distributions were compared by logistic regression. RESULTS: The 2119C variant was rare, occurring at frequencies of 1.4 and 1.3% in cases and controls, respectively (P = 0.8). There was no difference in genotype distribution between cases and controls (P = 0.8), and the TC genotype was not associated with increased risk of breast cancer (adjusted odds ratio = 1.08, 95% confidence interval = 0.59–1.97, P = 0.8). Similarly, the 3161G variant was no more common in cases than in controls (2.9% versus 2.2%, P = 0.2), there was no difference in genotype distribution between cases and controls (P = 0.1), and the CG genotype was not associated with an increased risk of breast cancer (adjusted odds ratio = 1.30, 95% confidence interval = 0.85–1.98, P = 0.2). This lack of evidence for an association persisted within groups defined by the family history of breast cancer or by age. CONCLUSION: The 2119C and 3161G amino acid substitution variants are not associated with moderate or high risks of breast cancer in Australian women

What environmental transmission electron microscopy measures and how this links to diffusivity: thermodynamics versus kinetics

Environmental or in situ electron microscopy means the observation of material in its native environment, which can be gaseous or liquid, as compared to more traditional post-mortem electron microscopy carried out under (ultra) high vacuum conditions. Experiments can be performed on bulk samples in scanning electron microscopes or on thinned samples in transmission (scanning) electron microscopes. In the latter, the movement, in real time and in situ, of nanoparticles, clusters or even single atoms on the surfaces of thinned material or within a liquid can be observed. It is argued here that due to the changes that a specimen typically undergoes during in situ observation, electron irradiation effects are difficult to evaluate and so thermodynamic parameters, such as activation energies for diffusion and segregation, which are governed by movements of only a minority of atoms in the specimen, cannot be reliably determined because of the potentially high energy transfer by the irradiating electron beam to some atoms in the sample. In order to measure diffusivities reliably, radiation effects and surface diffusion need to be excluded or kept minimal so as not to disturb the measurements, which can be checked by repeating experiments and comparing results as function of time and dose for the same position, at different positions or for different specimen thicknesses. Kinetic measurements of nucleation and growth phenomena, such as Ostwald ripening, are possibly influenced to a far lesser degree by irradiation effects, as a majority of atoms actively participate in these processes and if a small fraction of them will get extra energy from the irradiation process then their influence on the overall kinetics may be rather minor

Reproductive morbidity among Iranian women; issues often inappropriately addressed in health seeking behaviors

<p>Abstract</p> <p>Background</p> <p>Reproductive morbidity has a huge impact on the health and quality of life of women. We aimed to determine the prevalence of reproductive morbidities and the health seeking behavior of a nationally representative sample of Iranian urban women.</p> <p>Methods</p> <p>A sample of 1252 women, aged 18-45 years, was selected using the multi stage, stratified probability sampling procedure. Data were collected through interviews and physical, gynecological and ultrasonographic examinations.</p> <p>Results</p> <p>Reproductive tract infection (RTIs), pelvic organ prolapse (POP) and menstrual dysfunction were the three main groups of morbidities with a prevalence of 37.6%, 41.4% and 30.1%., respectively. Our study demonstrated that 35.1, 34.5 and 9.6 percent of women experienced one, two or these reproductive organ disorders mentioned, respectively, while 20.6 percent of participants had none of these disorders. Findings also showed that the majority of women who suffered from reproductive morbidities (on average two out of three) had not sought appropriate care for these except for infertility.</p> <p>Conclusions</p> <p>Reproductive health morbidities impose a large burden among Iranian women and have negative impact on their reproductive health and wellbeing.</p