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The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.
The anti-inflammatory mechanisms of low-fat dairy product consumption are largely unknown. The objective of this study was to determine whether low-fat yogurt reduces biomarkers of chronic inflammation and endotoxin exposure in women. Premenopausal women (BMI 18·5–27 and 30–40 kg/m2) were randomised to consume 339 g of low-fat yogurt (yogurt non-obese (YN); yogurt obese (YO)) or 324 g of soya pudding (control non-obese; control obese (CO)) daily for 9 weeks (n 30/group). Fasting blood samples were analysed for IL-6, TNF-α/soluble TNF II (sTNF-RII), high-sensitivity C-reactive protein, 2-arachidonoyl glycerol, anandamide, monocyte gene expression, soluble CD14 (sCD14), lipopolysaccharide (LPS), LPS binding protein (LBP), IgM endotoxin-core antibody (IgM EndoCAb), and zonulin. BMI, waist circumference and blood pressure were also determined. After 9-week yogurt consumption, YO and YN had decreased TNF-α/sTNFR-RII. Yogurt consumption increased plasma IgM EndoCAb regardless of obesity status. sCD14 was not affected by diet, but LBP/sCD14 was lowered by yogurt consumption in both YN and YO. Yogurt intervention increased plasma 2-arachidonoylglycerol in YO but not YN. YO peripheral blood mononuclear cells expression of NF-κB inhibitor α and transforming growth factor β1 increased relative to CO at 9 weeks. Other biomarkers were unchanged by diet. CO and YO gained approximately 0·9 kg in body weight. YO had 3·6 % lower diastolic blood pressure at week 3. Low-fat yogurt for 9 weeks reduced biomarkers of chronic inflammation and endotoxin exposure in premenopausal women compared with a non-dairy control food. This trial was registered as NCT01686204.
The phenotype of the human embryo conceived through in vitro fertilization (IVF), that is its morphology, developmental kinetics, physiology and metabolism, can be affected by numerous components of the laboratory and embryo culture system (which comprise the laboratory environment). The culture media formulation is important in determining embryo phenotype, but this exists within a culture system that includes oxygen, temperature, pH and whether an embryo is cultured individually or in a group, all of which can influence embryo development. Significantly, exposure of an embryo to one suboptimal component of the culture system of laboratory typically predisposes the embryo to become more vulnerable to a second stressor, as has been well documented for atmospheric oxygen and individual culture, as well as for oxygen and ammonium. Furthermore, the inherent viability of the human embryo is derived from the quality of the gametes from which it is created. Patient age, aetiology, genetics, lifestyle (as well as ovarian stimulation in women) are all known to affect the developmental potential of gametes and hence the embryo. Thus, as well as considering the impact of the IVF laboratory environment, one needs to be aware of the status of the infertile couple, as this impacts how their gametes and embryos will respond to an in vitro environment. Although far from straight forward, analysing the interactions that exist between the human embryo and its environment will facilitate the creation of more effective and safer treatments for the infertile couple.
It is increasingly essential for medical researchers to be literate in statistics, but the requisite degree of literacy is not the same for every statistical competency in translational research. Statistical competency can range from ‘fundamental’ (necessary for all) to ‘specialized’ (necessary for only some). In this study, we determine the degree to which each competency is fundamental or specialized.
We surveyed members of 4 professional organizations, targeting doctorally trained biostatisticians and epidemiologists who taught statistics to medical research learners in the past 5 years. Respondents rated 24 educational competencies on a 5-point Likert scale anchored by ‘fundamental’ and ‘specialized.’
There were 112 responses. Nineteen of 24 competencies were fundamental. The competencies considered most fundamental were assessing sources of bias and variation (95%), recognizing one’s own limits with regard to statistics (93%), identifying the strengths, and limitations of study designs (93%). The least endorsed items were meta-analysis (34%) and stopping rules (18%).
We have identified the statistical competencies needed by all medical researchers. These competencies should be considered when designing statistical curricula for medical researchers and should inform which topics are taught in graduate programs and evidence-based medicine courses where learners need to read and understand the medical research literature.
We report the observation of two isolated clouds of positrons inside an active thunderstorm. These observations were made by the Airborne Detector for Energetic Lightning Emissions (ADELE), an array of six gamma-ray detectors, which flew on a Gulfstream V jet aircraft through the top of an active thunderstorm in August 2009. ADELE recorded two 511 keV gamma-ray count rate enhancements, 35 s apart, each lasting approximately 0.2 s. The enhancements, which were approximately a factor of 12 above background, were both accompanied by electrical activity as measured by a flat-plate antenna on the underside of the aircraft. The energy spectra were consistent with a source mostly composed of positron annihilation gamma rays, with a prominent 511 keV line clearly visible in the data. Model fits to the data suggest that the aircraft was briefly immersed in clouds of positrons, more than a kilometre across. It is not clear how the positron clouds were created within the thunderstorm, but it is possible they were caused by the presence of the aircraft in the electrified environment.
Course viability requires dealing with issues of adequate class size, diversity of academic background and goals, English fluency, heavy content and more. To this end, for thirteen years a consortium of five Virginia universities, including an HBCU, has shared a first-year graduate course on materials characterization. The journey began with just classroom co-presence. The present state includes common-server availability of materials (presentation slides, background articles, e-books), of content-delivery lectures (“full flip”) and of recorded class sessions (all). The most significant current issue is making effective use of the extensive in-class discussion time now made available by flipping.
Successful management of downy brome (also known as cheatgrass) requires understanding land managers' perceptions and decisions about whether to invest in its control. We investigated ranchers' and natural resource professionals' (NRPs) perceptions and knowledge about downy brome ecology and its impacts, their current downy brome management practices and satisfaction with those practices, and their information and technical needs using focus groups and a mail survey of ranchers and NRPs in Colorado and Wyoming. Both groups thought downy brome was a problem, and perception of the severity of downy brome corresponded to the level of infestation in the respondent's region. NRPs identified downy brome as a bigger problem than did ranchers from the same area in all but one region. Ranchers were most likely to use early spring grazing to control downy brome, and NRPs were most likely to use seeding, imazapic herbicide, or a combination of methods. Both groups reported that the primary constraint to controlling downy brome was that other weeds were a higher priority. Ranchers and NRPs wanted more information about the control methods they were already likely to use as well as other downy brome control methods. Our findings suggest that (1) listing a species as a noxious weed may provide an important incentive to control it, but trade-offs among control efforts for different species must be carefully considered; (2) managers need to know more about low-cost, low-labor strategies for managing downy brome; and (3) some managers need to be informed about how to identify downy brome, its potential negative effects, and how to prevent its spread. Better quantification of the economic and ecological impacts of downy brome in the Central Rocky Mountains, continued development of effective and economically viable management methods, and improvement in the dissemination of that information to land managers are necessary for successful control of downy brome.
The propagation of a premixed flame inside of a confining vessel filled with combustible fluid is determined using large-activation-energy asymptotics. The flame structure is analysed assuming that spatial and temporal variations in the transverse direction are weak compared to those in the direction normal to the flame surface. The analysis considers weak pressure rise from confinement and also allows for mixtures that are both near and removed from stoichiometry, non-unity reaction orders, temperature-dependent transport coefficients, and general Lewis numbers. The resulting equations for flame propagation speed are expressed in a coordinate-free form and describe the evolution of an arbitrary shaped flame in a general confining flow. These expressions are specifically applied to the case of a spherical flame propagating inside a spherical chamber. The radius at which the confining vessel influences the flame propagation is determined and the various mechanisms influencing flame behaviour are discussed. The results give rise to a simplified asymptotic relationship that provides an improved equation that may be used to more accurately extrapolate unstretched laminar flame speeds from experimental measurements.
To examine the reliability and convergent validity of physical activity (PA) and inactivity estimates obtained with the past-week Modifiable Activity Questionnaire (PWMAQ).
The PWMAQ, an interviewer-administered questionnaire, was administered twice, one week apart, during visits 3 and 4 of six total visits. Intra-class correlation coefficients (ICC) between administrations of the PWMAQ were used to assess the reliability of summary estimates. Spearman rank-order correlation coefficients (ρ) were used to examine the associations of PWMAQ summary estimates with temporally matched and averaged accelerometer data in all participants and then stratified by whether the data were reflective of usual PA.
Data were obtained from the Evaluation of Physical Activity Measures in Middle-Aged Women (PAW) study.
Sixty-six women, mean age 52·6 (sd 5·4) years.
The reliability of the PWMAQ physical inactivity estimate suggested substantial agreement over one week (ICC = 0·77, 95 % CI 0·57, 0·82; P < 0·0001). With the exception of light-intensity PA, the PWMAQ leisure PA estimate was significantly associated with averaged accelerometer data (ρ = 0·33–0·76; P < 0·05). For both temporally matched and averaged accelerometer data, correlation coefficients were higher between the PWMAQ estimate and moderate-walk- to vigorous-intensity PA in those who indicated that reported activity was reflective of usual PA; however, the association with moderate-lifestyle-intensity PA was higher in those reporting that data were not reflective.
The PWMAQ is a reliable and valid measure of leisure PA levels in middle-aged women and supports subsequent studies evaluating this questionnaire in other population subgroups.
The health benefits of pomegranate consumption have recently received considerable scientific focus, with most studies examining fruit and/or juice consumption. Pomegranate seed oil (POMo) is a rich source of 9-cis, 11-trans conjugate linolenic acid (CLA), which may offset the side-effects associated with weight gain. Male, wild-type CD-1 mice were divided into one of three groups (twenty per group): high-fat (HF), HF+seed oil (HF+POMo) or lean control (LN). In HF and HF+POMo, mice were provided access ad libitum to a high-fat chow (60 % of energy from fat). HF+POMo was supplemented with 61·79 mg POMo/d. LN consumed a restricted low-fat (10 % of energy from fat) chow to maintain body weight within 5 % of initial weight. Plasma was analysed for biomarkers associated with cholesterol profile (total cholesterol, HDL and TAG), glucose sensitivity (glucose and insulin), adipose tissue accumulation (leptin and adiponectin) and systemic low-grade inflammation (C-reactive protein and haptoglobin). The key findings of this study were that weight gain was associated with an increase in biomarkers of cholesterol profile, glucose sensitivity, adipose tissue accumulation and systemic low-grade inflammation (P < 0·05). POMo only altered body weight accumulation, final body weight, leptin, adiponectin and insulin (P < 0·05). We found that despite a similar level of energy intake, HF mice had a greater concentration of leptin and a lower concentration of adiponectin compared to HF+POMo mice. POMo intake was associated with an improvement in insulin sensitivity, suggesting that risk of developing type 2 diabetes may have been reduced; however, CVD risk did not change.
The induction of general anaesthesia is associated with the greatest cardiovascular changes in elderly patients. Induction can be performed either intravenously or with gaseous induction. Sevoflurane has advantages over propofol for induction of anaesthesia in the elderly, since the lower reduction in mean arterial pressure with sevoflurane is both statistically and clinically significant. This prospective randomized controlled trial investigated the cardiovascular benefits of co-induction of anaesthesia with 0.75 mg kg−1 propofol and 8% sevoflurane, when compared with 8% sevoflurane alone in patients requiring surgery for fractured neck of femur.
In total, 38 patients aged 75 or over were allocated into the two groups, receiving either 0.75 mg kg−1 of propofol followed by 8% sevoflurane or 8% sevoflurane alone. Vital signs were recorded until successful insertion of a laryngeal mask. Induction times, induction events and patient satisfaction scores were also recorded.
Results showed that there were no differences in the cardiovascular parameters between the two groups. Induction times were faster in the propofol and sevoflurane group (62 vs. 81 s; P = 0.028). The postoperative questionnaire showed that the majority of patients in both groups were satisfied with the induction process.
We concluded that 0.75 mg kg−1 of propofol followed by sevoflurane induction is an acceptable alternative to sevoflurane induction. It is associated with similar haemodynamic variables, faster induction times and is very well tolerated.
There has long been a drive to produce sensors with ever-increasing sensitivity and selectivity, while also achieving robustness and ease of use. Nanoparticle-based sensing approaches have generated a great deal of attention and excitement, because they possess such qualities. For these assays to function properly, it requires the integration of molecular recognition motifs and materials with outstanding optical properties. Aptamers are DNA or RNA sequences that bind analytes with high specificity, which makes them a suitable choice as recognition elements. Changes in the surface plasmon resonance (SPR) of gold nanoparticles (AuNPS) as a function of interparticle distance, has been used as an optical signal to detect the presence of different species in solution by the naked eye. In this work, we coated gold nanoparticles with short oligonucleotides and aptamers for the design of sensors that can be used under different conditions, including salt concentration, pH and temperatures. Three aptamer sensors were developed using this approach 1) riboflavin, as a general indicator of biological activity, 2) ricin, a toxin that is of broad interest, and 3) theophylline, an adenosine antagonist. Our designs are based on two approaches, the first method consisted of the use of two sets of AuNPs, each coated with a short oligonucleotide complementary to a different part of the sequence of the aptamer of interest. Hybridization of the DNA-coated particles (DNA-AuNPs) with the free aptamer produced aggregates, i.e. 3-part design. The second approach consisted of the use of only two sets of DNA-AuNPs, one coated with an aptamer that contains a thiol group in its 5′ end, and the second set of AuNPs coated with a sequence complementary to part of the aptamer. Hybridization of these two sets of particles produced aggregates, i.e. 2-part design. In both cases, the presence of the analyte promoted a change in the conformation of the aptamer, which caused the dehybridization of the complementary sequences. This conformational change of the aptamer upon binding of the analyte produced the dissociation of the nanoparticle aggregates, which is translated into a change in the color of the suspensions from blue to red. In this presentation, we will compare the advantages and disadvantages associated with a 3-part versus a 2-part nanoparticle-oligonucleotide reporting assay.
A multi-faceted, multi-institutional laboratory astrophysics program is carried out at the Livermore electron beam ion trap facility, which is a mature spectroscopic source with unsurpassed controls and capabilities, and an unparalleled assortment of spectroscopic equipment, including a full complement of grating and crystal spectrometers and a 6x6 micro-calorimeter array. Recent results range from the calibration of x-ray diagnostics, including the Fe XVII and Fe XXV emission lines, extensive lists of L-shell ions, the first laboratory simulation and fit of a cometary x-ray emission spectrum, and the discovery of new spectral diagnostics for measuring magnetic field strengths.
We describe a > 100 Watt broadband THz source that takes advantage of the relativistic enhancement of the radiation from accelerating electrons according to the formula assigned the name of Sir Joseph Larmor[1, 2]. This is in contrast to the typical 1 milliwatt sources available in a laboratory. Specifically, for relativistic electrons the emission is enhanced by the fourth power of the increase in mass. Thus for 100 MeV electrons, for which the mass increases by a factor of ∼ 200, the enhancement is > 109. The experiments use a new generation of light source called an energy recovery linac (ERL) , in which bunches of electrons circulate once, but in which their energy is recovered. In such a machine the electron bunches can be very much shorter than those, say, in storage rings or synchrotrons.
The Jefferson Lab facility operates in new limits of emission from relativistic particles involving both multiparticle coherence and near-field emission in which the velocity (Coulomb) term in the classical electrodynamical theory becomes as important as the acceleration term (synchrotron radiation).
The sub-picosecond pulses of light offer unique capabilities in 2 specific areas, namely time-resolved dynamics, and imaging. High resolution THz spectroscopy has recently revealed sharp vibrational modes for many materials including malignant tissue, proteins, DNA, pharmaceuticals and explosive materials. Energetically the THz range embraces superconducting bandgaps, and regions of intense interest in the understanding of systems in which correlated motions of electrons are important, such as colossal magneto-resistive and high-Tc materials. The very high power levels of the new source will allow non-linear effects to be observed as well as the creation of novel states of materials, including electric-field driven localization. We will give examples of existing work in these areas and present opportunities afforded by the new source.