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Streamwise velocity and wall-shear stress are acquired simultaneously with a hot-wire and an array of azimuthal/spanwise-spaced skin friction sensors in large-scale pipe and boundary layer flow facilities at high Reynolds numbers. These allow for a correlation analysis on a per-scale basis between the velocity and reference skin friction signals to reveal which velocity-based turbulent motions are stochastically coherent with turbulent skin friction. In the logarithmic region, the wall-attached structures in both the pipe and boundary layers show evidence of self-similarity, and the range of scales over which the self-similarity is observed decreases with an increasing azimuthal/spanwise offset between the velocity and the reference skin friction signals. The present empirical observations support the existence of a self-similar range of wall-attached turbulence, which in turn are used to extend the model of Baars et al. (J. Fluid Mech., vol. 823, p. R2) to include the azimuthal/spanwise trends. Furthermore, the region where the self-similarity is observed correspond with the wall height where the mean momentum equation formally admits a self-similar invariant form, and simultaneously where the mean and variance profiles of the streamwise velocity exhibit logarithmic dependence. The experimental observations suggest that the self-similar wall-attached structures follow an aspect ratio of
in the streamwise, spanwise and wall-normal directions, respectively.
This study presents findings from a first-of-its-kind measurement campaign that includes simultaneous measurements of the full velocity and vorticity vectors in both pipe and boundary layer flows under matched spatial resolution and Reynolds number conditions. Comparison of canonical turbulent flows offers insight into the role(s) played by features that are unique to one or the other. Pipe and zero pressure gradient boundary layer flows are often compared with the goal of elucidating the roles of geometry and a free boundary condition on turbulent wall flows. Prior experimental efforts towards this end have focused primarily on the streamwise component of velocity, while direct numerical simulations are at relatively low Reynolds numbers. In contrast, this study presents experimental measurements of all three components of both velocity and vorticity for friction Reynolds numbers
ranging from 5000 to 10 000. Differences in the two transverse Reynolds normal stresses are shown to exist throughout the log layer and wake layer at Reynolds numbers that exceed those of existing numerical data sets. The turbulence enstrophy profiles are also shown to exhibit differences spanning from the outer edge of the log layer to the outer flow boundary. Skewness and kurtosis profiles of the velocity and vorticity components imply the existence of a ‘quiescent core’ in pipe flow, as described by Kwon et al. (J. Fluid Mech., vol. 751, 2014, pp. 228–254) for channel flow at lower
, and characterize the extent of its influence in the pipe. Observed differences between statistical profiles of velocity and vorticity are then discussed in the context of a structural difference between free-stream intermittency in the boundary layer and ‘quiescent core’ intermittency in the pipe that is detectable to wall distances as small as 5 % of the layer thickness.
Fully resolved measurements of turbulent boundary layers are reported for the Reynolds number range
. Despite several decades of research in wall-bounded turbulence there is still controversy over the behaviour of streamwise turbulence intensities near the wall, especially at high Reynolds numbers. Much of it stems from the uncertainty in measurement due to finite spatial resolution. Conventional hot-wire anemometry is limited for high Reynolds number measurements due to limited spatial resolution issues that cause attenuation in the streamwise turbulence intensity profile near the wall. To address this issue we use the nano-scale thermal anemometry probe (NSTAP), developed at Princeton University to conduct velocity measurements in the high Reynolds number boundary layer facility at the University of Melbourne. The NSTAP has a sensing length almost one order of magnitude smaller than conventional hot-wires. This enables us to acquire fully resolved velocity measurements of turbulent boundary layers up to
. Results show that in the near-wall region, the viscous-scaled streamwise turbulence intensity grows with
in the Reynolds number range of the experiments. A second outer peak in the streamwise turbulence intensity is also shown to emerge at the highest Reynolds numbers. Moreover, the energy spectra in the near-wall region show excellent inner scaling over the small to moderate wavelength range, followed by a large-scale influence that increases with Reynolds number. Outer scaling in the outer region is found to collapse the energy spectra over high wavelengths across various Reynolds numbers.
The importance of parasites as a selective force in host evolution is a topic of current interest. However, short-term ecological studies of host–parasite systems, on which such studies are usually based, provide only snap-shots of what may be dynamic systems. We report here on four surveys, carried out over a period of 12 years, of helminths of spiny mice (Acomys dimidiatus), the numerically dominant rodents inhabiting dry montane wadis in the Sinai Peninsula. With host age (age-dependent effects on prevalence and abundance were prominent) and sex (female bias in abundance in helminth diversity and in several taxa including Cestoda) taken into consideration, we focus on the relative importance of temporal and spatial effects on helminth infracommunities. We show that site of capture is the major determinant of prevalence and abundance of species (and higher taxa) contributing to helminth community structure, the only exceptions being Streptopharaus spp. and Dentostomella kuntzi. We provide evidence that most (notably the Spiruroidea, Protospirura muricola, Mastophorus muris and Gongylonema aegypti, but with exceptions among the Oxyuroidae, e.g. Syphacia minuta), show elements of temporal-site stability, with a rank order of measures among sites remaining similar over successive surveys. Hence, there are some elements of predictability in these systems.
Improving understanding of the pathogen-specific seasonality of enteric infections is critical to informing policy on the timing of preventive measures and to forecast trends in the burden of diarrhoeal disease. Data obtained from active surveillance of cohorts can capture the underlying infection status as transmission occurs in the community. The purpose of this study was to characterise rotavirus seasonality in eight different locations while adjusting for age, calendar time and within-subject clustering of episodes by applying an adapted Serfling model approach to data from a multi-site cohort study. In the Bangladesh and Peru sites, within-subject clustering was high, with more than half of infants who experienced one rotavirus infection going on to experience a second and more than 20% experiencing a third. In the five sites that are in countries that had not introduced the rotavirus vaccine, the model predicted a primary peak in prevalence during the dry season and, in three of these, a secondary peak during the rainy season. The patterns predicted by this approach are broadly congruent with several emerging hypotheses about rotavirus transmission and are consistent for both symptomatic and asymptomatic rotavirus episodes. These findings have practical implications for programme design, but caution should be exercised in deriving inferences about the underlying pathways driving these trends, particularly when extending the approach to other pathogens.
Selenium (Se) is a dietary trace mineral for poultry. Organic Se such as selenomethionin (SM) increases plasma Se more affectively than inorganic forms such as sodium selenite (SS) (Payne and Southern 2005). Thyroxine 5’-deiodinase-1 (D1) is a selenoenzyme in liver which converts T4 to T3 (main thyroid hormone in poultry) and produces 95% of plasma T3 (Bianco et. al. 2002). This study describes the effects of SM (Biokey® Selen) versus SS on growth performance and plasma level of thyroid hormones by using different levels of dietary energy.
The focus of Commission 12 is on the solar interior, on global phenomena of the quiet Sun, and on the Sun’s radiative outputs, both spectral and total. These are the topics treated below in our discussion of Scientific Highlights. The many topics having to do with solar activity at photospheric to coronal levels, are dealt with in the report by Commission 10, while the report of Commission 49 describes research on the solar wind and interplanetary medium.
In order to potentially realize the advantages of planar parallel manipulators to be used for hybrid machine tools, the inherently abundant singularities which diminish the usable workspace must be eliminated. Proper structure synthesis and dimensional synthesis can provide a good solution. So, a non-conventional architecture of a three-PPR planar parallel manipulator is proposed in this paper for a hybrid machine tool. The proposed architecture permits a large dexterous workspace with unlimited orientation capability and no singularities. It also provides partially decoupled motion which permits independent actuators control. The kinematic, singularity, orientation capability and workspace analyses of the proposed manipulator are studied to verify those advantages. Based on a non-dimensional design parameter space, the highly important indices for this application namely the workspace index (WI), the motion/force transmission index, the kinematic and dynamic dexterity indices and the stiffness index are selected to be maximized yielding proper dimensions of the design parameters. Those performance indices are proven to be uniform over all the workspace achieving highly important characteristics of uniform accuracy, acceleration characteristics, rigidity and force transmissibility. Performance evaluation is finally presented to verify the high performance of the proposed non-singular planar parallel manipulator with high orientation capability.
To study (i) the current prevalence of iodine-deficiency disorders among schoolchildren in south-western Saudi Arabia after universal salt iodization and (ii) the iodine content of table salts and water.
Cross-sectional study on a stratified proportional allocation sample of children. Thyroid gland enlargement was assessed clinically and by ultrasound scanning. Urine, table salt and water samples were taken to measure iodine content.
The Aseer region, south-western Saudi Arabia.
Schoolchildren aged 8–10 years.
The study included 3046 schoolchildren. The total goitre rate amounted to 24·0 %. Prevalence of enlarged thyroid by ultrasound was 22·7 %. The median urinary iodine concentration of the study sample amounted to 17·0 µg/l. The iodine content of table salt ranged from 0 to 112 mg/kg; 22·5 % of the table salt samples were below the recommended iodine content (15 mg/kg) set by WHO. The total goitre rate increased significantly from 19·8 % among children using table salt with iodine content ≥15 mg/kg to reach 48·5 % among children using table salt with 0 mg iodine/kg. Analysis of water samples taken from schools showed that the majority of water samples (78·8 %) had an iodine content of 0 µg/l.
The study documented that 18 years after the national study, and after more than a decade of universal salt iodization in Saudi Arabia, the problem of iodine-deficiency disorders is still endemic in the Aseer region. Efforts should focus on fostering advocacy and communication and ensuring the availability of adequately iodized salt.
The Solar Orbiter is the next solar physics mission of the European Space Agency, ESA, in collaboration with NASA, with a launch planned in 2018. The spacecraft is designed to approach the Sun to within 0.28 AU at perihelion of a highly eccentric orbit. The proximity with the Sun will also allow its observation at uniformly high resolution at EUV and visible wavelengths. Such observations are central for learning more about the magnetic coupling of the solar atmosphere. At a later phase in the mission the spacecraft will leave the ecliptic and study the enigmatic poles of the Sun from a heliographic latitude of up to 33○.
A central instrument of Solar Orbiter} is the Polarimetric and Helioseismic Imager, SO/PHI. It will do full Stokes imaging in the Landé g = 2.5 Fe I 617.3 nm line. It is composed of two telescopes, a full-disk telescope and a high-resolution telescope, that will allow observations at a resolution as high as 200 km on the solar surface. SO/PHI will also be the first solar polarimeter to leave the Sun-Earth line, opening up new possibilities, such as stereoscopic polarimetry (besides stereoscopic imaging of the photosphere and stereoscopic helioseismology). Finally, SO/PHI will have a unique view of the solar poles, allowing not just more precise and exact measurements of the polar field than possible so far, but also enabling us to follow the dynamics of individual magnetic features at high latitudes and to determine solar surface and sub-surface flows right up to the poles.
In this paper an introduction to the science goals and the capabilities of SO/PHI will be given, as well as a brief overview of the instrument and of the current status of its development.
Eating breakfast may reduce appetite, body weight and CVD risk factors, but the breakfast type that produces the greatest health benefits remains unclear. We compared the effects of consuming a high-fibre breakfast, a non-fibre breakfast, or no-breakfast control on body weight, CVD risk factors and appetite. A total of thirty-six overweight participants (eighteen men and eighteen women) (mean age 33·9 (sd 7·5) years, mean BMI 32·8 (sd 4·7) kg/m2) were randomly assigned to consume oat porridge (n = 12), frosted cornflakes (n = 12) or a water control (n = 12) breakfast daily for 4 weeks. Appetite ratings were collected on the first day and weekly thereafter. Before and after the intervention, body weight, composition, blood pressure and resting energy expenditure (REE) were measured and a fasting blood sample was collected. Across the 4 weeks, fullness was higher and hunger was lower in the oat porridge group compared with the control group (P < 0·05). Mean weight change over the intervention was significantly different in the control group (−1·18 (sd 1·16) kg) compared with both the cornflakes (−0·12 (sd 1·34) kg) and oat porridge (+0·26 (sd 0·91) kg) groups (P < 0·05). However, the control group also showed elevated total cholesterol concentrations relative to the cornflakes and oat porridge groups (P < 0·05). There were no differences between groups in changes in body composition, blood pressure, REE or other CVD risk factors. In conclusion, although skipping breakfast led to weight loss, it also resulted in increased total cholesterol concentrations compared with eating either oat porridge or frosted cornflakes for breakfast.
A 15-year-old girl presenting with tachycardia, heat intolerance, and goiter is found to have elevated free thyroxin (FT4) and low thyroid-stimulating hormone (TSH) (FT4 = 6 ng/mL [normal: 2–4 ng/mL], serum TSH = 0.01 μIU/mL [normal: 1–5 μIU/mL]). The iodine-123 (123I) uptake and scan showed homogeneously increased radiotracer uptake. The isthmus and the pyramidal lobe were prominent. The 24 hours 123I neck uptake was 70% (normal: 10–30%) (Fig. 67.1). These features are typical of Graves’ disease.
Graves’ disease is an autoimmune disorder of multifactorial etiology and is the commonest cause of hyperthyroidism in children. The classic clinical triad of Graves’ disease includes hyperthyroidism, orbitopathy, and dermatopathy and is four to five times more frequent in girls. Peak incidence of Graves’ disease occurs in early adolescence. There is a familial predisposition; however, the hereditary component has not been clearly defined. Untreated Graves’ disease can lead to arrhythmia, heart failure, and cardiovascular collapse.
To compare the outcome among patients with invasive bladder cancer treated with cystectomy alone with outcome among those treated with combined-modality treatment in a randomised phase III trial.
Patients and methods
Patients with histologically confirmed invasive non-metastatic bladder cancer T2-3, N0 and M0 were randomly assigned to two arms: Arm 1: of which all patients underwent radical cystectomy (RC) alone; and Arm 2, of which all patients were subjected to maximal transurethral resection of bladder tumour, followed 2 weeks later by combined chemoradiotherapy. The whole pelvis received 46 Gy in 23 fractions over 4·5 weeks. Chemotherapy was administered concomitantly with radiotherapy with: cisplatin 70 mg/m2 q. 3 weeks and Gemcitabine 300 mg/m2 D 1, 8 and 15 q. 3 weeks for two cycles. Patients who had complete response were shifted to phase II treatment: 20 Gy/10 fractions/2 weeks to the bladder. Patients with residual tumour underwent RC.
Of the 80 patients assigned Arm 2, a visibly completed transurethral resection of the bladder tumour was possible in 48 patients (60%). Phase I of combined chemoradiotherapy (CCRT) was accomplished in 74 patients. Post-induction urologic evaluation revealed no evidence of disease in 62 patients (83·8%) and residual disease in 12 patients (16·2%). Phase II of CCRT was completed in 58 of the 62 patients. The median follow-up for all patients is 27 months (range: 4–49). The 3-year overall survival (OS) for the combined-modality group and for the surgery group were 61 and 63%, respectively (p = 0·425), whereas the disease-specific survival (DSS) for each group was 69 and 73%, respectively (p = 0·714). The 3-year OS with bladder preservation for Arm 2 patients was 50%.
Multivariate analysis for the whole series showed that tumour stage and performance status (PS) were the only factors independently associated with DSS, although PS was the only factor independently associated with OS. In addition, residual disease after transurethral resection of the bladder tumour in Arm 2 patients was independently associated with both DSS and OS.
Acute toxicity was moderate and most of the late toxicities were grade 2 with no grade 4 toxicity and no treatment-related deaths, none required cystectomy for bladder contraction.
This study demonstrates that trimodality bladder-preserving approach represents a valid alternative for suitable patients. The OS and DSS rates of patients treated with trimodality bladder-preserving protocol are comparable to the results reported on patients treated with immediate radical cystectomy.
Populations of many frogs have declined alarmingly in recent years, placing nearly one third of the > 6,000 species under threat of extinction. Declines have been attributed largely to habitat loss, environmental degradation and/or infectious diseases such as chytridiomycosis. Many frogs undergo dramatic natural population fluctuations such that long-term data are required to determine population trends without undue influence of stochastic factors. We present long-term quantitative data (individuals encountered per person hour of searching) for four monotypic frog genera endemic to an Afromontane region of exceptional importance but growing conservation concern: one endemic to the Ethiopian highlands (Spinophrynoides osgoodi) and three endemic to the Bale Mountains (Altiphrynoides malcolmi, Balebreviceps hillmani, Ericabatrachus baleensis), collected during 15 field trips to the Bale Mountains between 1971 and 2009. Only a single confirmed sighting of S. osgoodi has been made since 1995. The other three species have also declined, at least locally. E. baleensis appears to have been extirpated at its type locality and at the same site B. hillmani has declined. These declines are in association with substantial habitat degradation caused by a growing human population. Chytrid fungus has been found on several frog species in Bale, although no dead or moribund frogs have been encountered. These results expose an urgent need for more amphibian surveys in the Bale Mountains. Additionally, we argue that detrimental human exploitation must be halted immediately in at least some parts of the Harenna Forest if a conservation crisis is to be averted.
We present results on optical degradation of gallium nitride based materials under low energy electron beam irradiation (LEEBI). GaN thin film and GaN/InGaN quantum well samples, grown by metal-organic vapor phase epitaxy (MOVPE), were exposed to a tightly focused (ø = 2 nm, J = 0-130 kA/cm2), rapidly scanning electron beam (e-beam) with energy of 5-20 keV and dose of 0-500 μC/cm2. The irradiation severely reduced the band-to-band photoluminescence of the exposed sample areas. Performing positron annihilation spectroscopy measurements on the irradiated films revealed an important increase of Ga-vacancy concentration as a function of the irradiation dose. Based on the measurements we propose that in-grown passive VGa-Hn complexes are present in MOVPE grown GaN (and its alloys), and are activated by LEEBI.
We report on the development of W-band (75–110 GHz) heterodyne receiver technology for large-format astronomical arrays. The receiver system is designed to be both mass producible, so that the designs could be scaled to thousands of receiver elements, and modular. Most of the receiver functionality is integrated into compact monolithic microwave integrated circuit (MMIC) amplifier-based multichip modules. The MMIC modules include a chain of InP MMIC low-noise amplifiers, coupled-line bandpass filters, and sub-harmonic Schottky diode mixers. The receiver signals will be routed to and from the MMIC modules on a multilayer high-frequency laminate, which includes splitters, amplifiers, and frequency triplers. A prototype MMIC module has exhibited a band-averaged noise temperature of 41 K from 82 to 100 GHz and a gain of 29 dB at 15 K, which is the state-of-the-art for heterodyne multichip modules.