To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This paper describes the technical details and practical implementation of the phase synchronisation system selected for use by the Mid-Frequency Square Kilometre Array. Over a four-year period, the system has been tested on metropolitan fibre-optic networks, on long-haul overhead fibre at the South African Square Kilometre Array site, and on existing telescopes in Australia to verify its functional performance. The tests have shown that the system exceeds the 1-s Square Kilometre Array coherence loss requirement by a factor of 2 560, the 60-s coherence loss requirement by a factor of 239, and the 10-min phase drift requirement by almost five orders-of-magnitude. The paper also reports on tests showing that the system can operate within specification over all the required operating conditions, including maximum fibre link distance, temperature range, temperature gradient, relative humidity, wind speed, seismic resilience, electromagnetic compliance, frequency offset, and other operational requirements.
Non-completion of equestrian competition by competitors may occur for a variety of reasons. However, limited work has been conducted to establish the likely factors causing non-completion. Non-completion by a competitor needs to be carefully considered within any overall analysis of competition data. Non-completing competitors within sporting competitions are potential complicating and confounding factors in the analysis of performance data (Whitaker and Hill, in press). Within a population it is important to establish if there are systematic or nonrandom reasons for non completion; or whether non-completion is entirely a random event (Little and Rubin 1987). If systematic or nonrandom effects are occurring in competition they need to be considered carefully in the wider analysis of the whole population. This will include the application of appropriate statistical methods to the data sets. These may include such techniques as Regression Analysis, Approximate Bayesian Bootstrap, Hot Deck Method or Summary of Single Input Method (ibid).
Eventing is a three phased equestrian sport involving the completion of dressage, speed and endurance phases (cross country course) and show jumping phase. Penalty points are accrued during each phase of competition;. Competitors are ranked within competition on the basis of overall penalty points accrued (lowest points – winning the competition). The relative influence of each phase of the competition is currently being debated by the Federation Equestre Internationale (FEI) and its membership. The reasons for this, amongst other factors, include concerns over equine welfare, financial commitment to infrastructure and accessibility of nations developing within the sport. The essence of eventing, a speed and endurance contest, has been based around the cross country phase; the FEI refers to the phase as ‘the major test’ (FEI 2003) and British Eventing (BE) state ‘‘the relative influence on the whole competition exerted by dressage should be slightly more than that exerted by the show jumping, but considerably less than that exerted by the cross country’’ (BE 2004).
The assessment of dressage tests within equine competition is undertaken via a judge (or panel of up to three judges at the higher levels of the sport). Judges assess and award marks for a series of pre-determined movements; such marks are given in line with criteria laid down by relevant governing equestrian organisations. Additionally, judges undergo training and assessment designed to enable them to adhere to the required guidelines as closely as possible. The equestrian sport of eventing is a three phased sport consisting of the completion of a dressage test, speed and endurance test (cross country) and round of show jumps. The speed and endurance phase is considered the most important and influential phase of competition; the sport's governing body, the International Equestrian Federation (FEI), describe it as the ‘major test’ (FEI). Various authors (Duell and Russek-Cohen, 1995; Whitaker et al, 2004; Whitaker and Hill, 2005) have demonstrated that the dressage phase contributes to the largest percentage of penalty points within the overall final penalty score from all the phases of competition.
A greater understanding of the population characteristics of sport horse populations is required to enable potential breed improvement programmes to be formulated correctly and be effective in their outcomes. To date limited research has been conducted into the UK sport horse population.
A selected group of progeny (n=339) sired by elite eventing stallions was examined. In the context of this study elite sires were defined as those that were ranked 1-10 by total lifetime points won by competing progeny up to the end of 2000 (British Horse Database, 2000). Comparative analysis was undertaken between the selected group and all competing eventing horses in 2000 (n=9387) (British Horse Database, 2000). Data collected for both groups included, total lifetime points won at eventing and dressage and total lifetime money won at show jumping. Basic descriptive statistics were produced for each data set (Table 1). Product moment correlations were performed for all discipline areas (Table 2). Data transformation was applied using LOG+1(Hassenstein, Roehe, and Kalm, 1996).
The UK currently has limited success at producing show jumping horses of international standard (WBFSH, 2002). For improvement to occur a greater understanding of the population dynamics of the show jumping population is required
A selected group of progeny (n=304) sired by elite show jumping stallions was examined. Elite sires were defined as those that were ranked 1-10 in the 2001 Sport Horse Annual (British Horse Database, 2000) by total lifetime earnings of progeny competing in 2000. Comparative analysis was conducted with all competing show jumping horses (n=22421) in 2000 (British Horse Database, 2000). Data collected comprised of total lifetime money won at show jumping, total lifetime points won at eventing and dressage. Descriptive statistics were produced for each data set (Table 1). Product Moment Correlations were performed for all discipline areas (Table 2). Data transformation was applied using LOG+1(Hassenstein, Roehe and Kalm, 1996) to account for the skewness in all data sets.
Equine welfare is a major concern within the racing industry. A large proportion of fatalities (50-60%) are the result of falls at fences (Pinchbeck, et al., 2004). Various authors have reported factors affecting fall rates both within steeplechase and hurdle races these include; race length, race speed, ground conditions (the going), the horses Timeform rating, previous history, race progression and whip use (Pinchbeck, et al., 2003; Pinchbeck, et al., 2004). At present there have been few studies carried out investigating the effects of gender on the risk of falling in hurdle racing. This study undertook an investigation of fall rates for hurdlers running during the 2004/05 National Hunt season, discriminating via gender.
A week before the Reagan-Gorbachev summit in Washington, a group of American and Soviet scholars met in Moscow to explore how a new spirit of cooperation could be applied in Africa. The challenge was to find ways of transforming the well-established pattern of hostile competition between the two countries in that area of the world into one of collaboration for the mutual benefit of both countries and Africa. The results of the Moscow workshop are highly promising.
Oxidative stress and neurotrophic factors have been implicated in the pathophysiology of bipolar disorder. Our objective was to determine whether plasma glutathione or brain-derived neurotrophic factor (BDNF) levels were abnormal in bipolar disorder and therefore useful as possible biomarkers.
Blood samples were collected from subsyndromal, medicated bipolar I patients (n = 50), recruited from OXTEXT, University of Oxford, and from 50 matched healthy controls. Total and oxidized glutathione levels were measured using an enzymatic recycling method and used to calculate reduced, percentage oxidized, ratio of reduced:oxidized and redox state. BDNF was measured using an enzyme-linked immunoassay. Self-monitored mood scores for the bipolar group were available (Quick Inventory of Depressive Symptomatology and the Altman Self-Rating Mania Scale) over an 8-week period.
Compared with controls, bipolar patients had significantly lower levels of total glutathione and it was more oxidized. BDNF levels were not different. Age of illness onset but not current mood state correlated with total glutathione levels and its oxidation status, so that lower levels of total and reduced glutathione were associated with later onset of disease, not length of illness.
Plasma glutathione levels and redox state detect oxidative stress even in subsyndromal patients with normal BDNF. It may relate to the onset and development of bipolar disorder. Plasma glutathione appears to be a suitable biomarker for detecting underlying oxidative stress and for evaluating the efficacy of antioxidant intervention studies.
The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope1, MALT90 has obtained 3′ × 3′ maps towards ~2 000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to
regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38 arcsec) and spectral (0.11 km s−1) resolution, the data reveal a wealth of information about the clumps’ morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high-resolution studies with ALMA.
We characterise the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90) and the Mopra telescope at 90 GHz. We combine repeated position-switched observations of the source G300.968+01.145 with a map of the same source in order to estimate the pointing reliability of the position-switched observations and, by extension, the MALT90 survey; we estimate our pointing uncertainty to be 8 arcsec. We model the two strongest sources of systematic gain variability as functions of elevation and time-of-day and quantify the remaining absolute flux uncertainty. Corrections based on these two variables reduce the scatter in repeated observations from 12%–25% down to 10%–17%. We find no evidence for intrinsic source variability in G300.968+01.145. For certain applications, the corrections described herein will be integral for improving the absolute flux calibration of MALT90 maps and other observations using the Mopra telescope at 90 GHz.
The current study examined the use of biographical data to predict errors, tardiness, policy violations, overall job performance, and turnover among nurses. The results of the study indicate that biodata measures are valid selection devices for nurses and effective at predicting nurse errors, tardiness, policy violations, and overall job performance, but the instrument was not an effective predictor of turnover, voluntary or involuntary. Additionally, examination of group differences revealed that White subjects scored significantly higher on the biodata instrument compared to Black subjects but produced group differences considerably smaller than typically found with measures of cognitive ability. Future research directions and implications for practice are discussed.
The self-controlled case-series method was originally developed to investigate potential associations between vaccines and adverse events, and is now commonly used for this purpose. This study reviews applications of the method to vaccine safety investigations in the period 1995–2010. In total, 40 studies were reviewed. The application of the self-controlled case-series method in these studies is critically examined, with particular reference to the definition of observation and risk periods, control of confounders, assumptions and potential biases, methodological and presentation issues, power and sample size, and software. Comparisons with other study designs undertaken in the papers reviewed are also highlighted. Some recommendations are presented, with the emphasis on promoting good practice.
A study has been carried out on the evolution of light induced defects in protocrystalline (diluted) a-Si:H films under 1 sun illumination. A room temperature reversal is observed in the photocurrents at 25°C, which is consistent with the relaxation in the recombination currents on corresponding p-i-n solar cells. It is also consistent with the pressure of “fast” states such as have been observed after high intensity illumination. Even with the limitations imposed by the relaxation in the light induced changes on the subgap absorption measurements, the evolution of distinctly different gap states centered around 0.9 and 1.15eV from the conduction band was identified. The kinetics of the electron occupied states, kN(E), at these two energies is compared with that of the neutral dangling bond (D0) densities as measured with electron spin resonance. Because of the similarity between the preliminary results of these kinetics it has not been possible to identify which states correspond to the D0 nor to draw any reliable conclusions about the nature of the different states.
We report an essentially complete characterization of energies and relaxation processes of the lowest seven electronic states of the N-V (nitrogen-vacancy) center in diamond using several different nonlinear laser spectroscopie techniques. We have also applied ultrafast optical techniques to measure dielectric properties of CVD and bulk diamond in the 0.3–1.6 THz range for the first time.
One approach for structural health monitoring of aging aircraft is to take discrete airframe strain measurements and record the flight loads history. A complementary method consists of measuring changes in dynamic response due to fatigue crack growth. The challenge in implementing such methods is the need for inexpensive networks of distributed strain sensors which possess high resolution with no drift over time. The Uni-Axial Strain Transducer (UAST) has been developed as a digital, absolute encoding device to address these very issues. The UAST is a micro-electromechanical system (MEMS) which exploits the capacitive coupling between an array of electrostatic field emitters and an array of 64 field detectors on a CMOS IC chip. The slightly different array element spacings form a vernier scale and digital signal processing of the detector outputs is used to calculate the absolute translational displacement of the emitter array relative to the CMOS detector chip. The UAST provides a dynamic range of 11,500 μ-strain and displacements of 2.5 nm are easily resolved. The sensor sampling rate is dynamically configurable for 150, 290, 540, 1000, 1600 or 2500 Hz, providing 15, 14, 13, 12, 11, or 10 bits of resolution (equal to 0.35, 0.7, 1.4, 2.8, 5.6, or 11.4 μ-strain), respectively. The sensor network can communicate with up to 128 UASTs on a common 5-wire digital bus, eliminating the need for shielding and considerably reducing the number of wires which will have to be routed through the airframe. A network technology demonstration is being conducted on a 1/2 scale F-I 8 vertical tail where dynamic loads are applied to evaluate network performance related to monitoring of fatigue crack growth or rivet-line failures. Application of the UAST in a helicopter rotor health usage and monitoring system, and the design of a bi-axial transducer under development, are also mentioned.
We report the temperature dependence of the growth and decay of the optically induced electron spin resonance (LESR) on short and long time scales (10-3 s < t < 2500 s). This range of times spans the region between previously published photoluminescence and the LESR data. In addition, we examine the steady-state density of optically excited charge carriers as a function of temperature. These measurements lead to a better understanding of the band tail structure of amorphous silicon as well as the kinetics of the excitation and recombination processes.
Optically induced electron spin resonance (LESR) studies on time scales in between the previously published PL and LESR results (approximately 10 ms to 10 s) allow one to examine the cross over between energy-loss (downward) hopping of carriers and carrier recombination via tunneling. In addition, data in this time regime are directly compared in the same sample with NMR data on the dipolar spin-lattice relaxation of the bonded hydrogen where light induced electrons and holes are responsible for dipolar relaxation of bonded hydrogen. The LESR results confirm the interpretation of the NMR measurements.