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Exposure to adverse events is prevalent among youths and robustly associated with risk for depression, particularly during adolescence. The Dimensional Model of Adversity and Psychopathology (DMAP) distinguishes between adverse events that expose youths to deprivation versus threat, positing unique mechanisms of risk (cognitive functioning deficits for deprivation, and altered fear and emotion learning for threat) that may require different approaches to intervention. We examined whether deprivation and threat were distinctly associated with behavioral measures of cognitive processes and autonomic nervous system function in relation to depression symptom severity in a community sample of early adolescents (n = 117; mean age 12.73 years; 54.7% male). Consistent with DMAP, associations between threat and depression symptoms, and between economic deprivation and depression symptoms, were distinctly moderated by physiological and cognitive functions, respectively, at baseline but not follow-up. Under conditions of greater cognitive inhibition, less exposure to deprivation was associated with lower symptom severity. Under conditions of blunted resting-state autonomic response (electrodermal activity and respiratory sinus arrhythmia), greater exposure to threat was associated with higher symptom severity. Our findings support the view that understanding risk for youth depression requires parsing adversity: examining distinct roles played by deprivation and threat, and the associated cognitive and biological processes.
A two-year (2015 and 2016) grazing study was established to compare ewe and lamb performance when grazed on a perennial ryegrass only sward compared to more diverse sward types. In that study four sward types were investigated: a perennial ryegrass (Lolium perenne) only sward receiving 163 kg nitrogen per hectare per year (N/ha/yr) (PRG); a perennial ryegrass and white clover (Trifolium repens) sward receiving 90 kg N/ha/yr (PRGWC); a six species sward (two grasses (perennial ryegrass and timothy (Phleum pratense)), two legumes (white and red clover (Trifolium pratense)) and two herbs (ribwort plantain (Plantago lanceolata) and chicory (Cichorium intybus)) receiving 90 kg N/ha/yr (6S); and a nine species sward containing cocksfoot (Dactylis glomerata), greater birdsfoot trefoil (Lotus pedunculatus) and yarrow (Achillea millefolium) in addition to the six species listed above, receiving 90 kg N/ha/yr (9S). Each sward type was managed as a separate farmlet and stocked with 30 twin-rearing ewes at a stocking rate of 12.5 ewes/ha under rotational grazing management from turnout post-lambing until housing. Lamb live weight was recorded fortnightly and lambs were drafted for slaughter at 45 kg. Ewe live weight and body condition score (BCS) were recorded on five occasions annually. Lamb faecal egg count (FEC) was recorded fortnightly and lambs were treated with anthelmintics when mean lamb FEC per sward type was above 400 eggs per gram. Ewes grazing the 6S and 9S swards had heavier (P < 0.01) live weights and BCS throughout the study than the ewes grazing the PRG sward. Lambs grazing the 6S sward were heavier than lambs grazing all other sward types of 14 weeks old (P < 0.05). Lambs grazing the PRG sward required more days to reach slaughter weight than lambs grazing all other sward types (P < 0.001). Lambs grazing the 6S and 9S swards required fewer anthelmintic treatments than lambs grazing the PRG or PRGWC swards. In conclusion, grazing multispecies swards improved ewe and lamb performance and reduced the requirement for chemical anthelmintics.
We consider two isolated, interacting dust particles confined in plasma. Measurements of normal mode frequencies are used to determine the dust charge, the Debye shielding length and the anisotropy of the confining potential well. For dust particles confined near the sheath edge, the vertical electric field and an effective electron temperature are also determined. This method is used to characterize the sheath above a short rectangular trench in the powered electrode of a radio-frequency discharge.
In this paper we discuss 80 MHz heliograph observations of the multiple source structure and polarization of a type IV solar radio outburst on 1970 November 16. At times during the event six sources were present. Three of these were highly circularly polarized in a L.H. sense and two in a R.H. sense. The sixth source was extended and had oppositely polarized edges. From the source behaviour we conclude that the radio emission came from two expanding and one stationary magnetic arch.
We present a catalogue of 668 major metre-wavelength radio events. The data was collected from dynamic spectra (taken at Dapto, N.S.W. until 1966 and at Culgoora, N.S.W. thereafter) by means of a radio spectrograph, which records the intensity of radio emission as a function of both frequency and time. A description of the major types of metre-wavelength phenomena can be found in Wild et al. (1963), Kundu (1965), Wild and Smerd (1972) and Kruger (1979), and details of the radio spectrograph in Sheridan (1963, 1967) and Labrum (1972).
Travelling disturbances in the solar corona with velocities ~103 km/s manifest themselves at radio frequencies by two distinctive phenomena—the type II burst, the spectrum of which shows a slow frequency drift that corresponds to quasi-radial outward motion, and the moving type IV burst, for which positional observations show transverse motion directly. A close relation between the two phenomena has long been suspected, and each type has separately been ascribed to a shock wave disturbance. In this paper we summarize three events recorded by the Culgoora radioheliograph and spectograph (two in the course of publication and one unpublished) in each of which a type II and a moving type IV burst can be consistently attributed to the effects of a common shock wave.
Observations on 1970 August 11 and 12 at Mauna Loa (Hawaii) of the white-light corona revealed a rare solar event in the form of a short-lived coronal brightening off the eastern limb of the Sun. The intensity of this region, as measured at a distance ρ = 1.5 (where ρ = R/R⊙), more than doubled over a period of five hours and then fell very abruptly (~10 min) to below its initial brightness. A complex radio event in the same region was observed simultaneously with the 80 MHz radioheliograph at Culgoora (Australia). Associations between the optical and radio events will be described and the physical implications briefly discussed.
The effects of advance ratio and the wing’s aspect ratio on the structure of the leading-edge vortex (LEV) that forms on flapping and rotating wings under insect-like flight conditions are not well understood. However, recent studies have indicated that they could play a role in determining the stable attachment of the LEV. In this study, a numerical model of a flapping wing at insect Reynolds numbers is used to explore the effects of these parameters on the characteristics and stability of the LEV. The word ‘stability’ is used here to describe whether the LEV was attached throughout the stroke or if it was shed. It is demonstrated that increasing the advance ratio enhances vorticity production at the leading edge during the downstroke, and this results in more rapid growth of the LEV for non-zero advance ratios. Increasing the wing aspect ratio was found to have the effect of shortening the wing’s chord length relative to the LEV’s size. These two effects combined determine the stability of the LEV. For high advance ratios and large aspect ratios, the LEV was observed to quickly grow to envelop the entire wing during the early stages of the downstroke. Continued rotation of the wing resulted in the LEV being eventually shed as part of a vortex loop that peels away from the wing’s tip. The shedding of the LEV for high-aspect-ratio wings at non-zero advance ratios leads to reduced aerodynamic performance of these wings, which helps to explain why a number of insect species have evolved to have low-aspect-ratio wings.
Wing deformation is observed during the flight of some insect species; however, the effect of these distorted wing shapes on the leading edge vortex (LEV) is not well understood. In this study, we investigate the effect of one of these deformation parameters, (rigid) wing camber, on the flow structures and aerodynamic forces for insect-like wings, using a numerical model of an altered fruit fly wing revolving at a constant angular velocity. Both positive and negative camber was investigated at Reynolds numbers of 120 and 1500, along with the chordwise location of maximum camber. It was found that negatively cambered wings produce very similar LEV structures to non-cambered wings at both Reynolds numbers, but high positive camber resulted in the formation of multiple streamwise vortices at the higher Reynolds number, which disrupt the development of the main LEV. Despite this, positively cambered wings were found to produce higher lift to drag ratios than flat or negatively cambered wings. It was determined that a region of low pressure near the wing’s leading edge, combined with the curvature of the wing’s upper surface in this region, resulted in a vertical tilting of the net force vector for positively cambered wings, which explains how insects can benefit from wing camber.
A foodborne outbreak with 49 cases (22 culture positive for Campylobacter sp.) following a wedding party in the East of England was investigated. A retrospective cohort study identified an association between consumption of chicken liver pâté and infection with Campylobacter jejuni/coli. There was a statistically significant association between dose (amount of chicken liver pâté eaten) and the risk of disease [‘tasted’: odds ratio (OR) 1·5, 95% confidence interval (CI) 0·04–∞; ‘partly eaten’: OR 8·4, 95% CI 1·4–87·5; ‘most or all eaten’: OR 36·1, 95% CI 3·3–2119). The local authority found evidence that the preparation of chicken livers breached Food Standards Agency's guidelines. This epidemiological investigation established a clear dose–response relationship between consumption of chicken liver pâté and the risk of infection with Campylobacter. The continuing need to raise public awareness of the risk to human health posed by undercooked chicken liver is evident.
Previous studies investigating the effect of aspect ratio (
) for insect-like regimes have reported seemingly different trends in aerodynamic forces, however no detailed flow observations have been made. In this study, the effect of
and Reynolds number on the flow structures over insect-like wings is explored using a numerical model of an altered fruit fly wing revolving at a constant angular velocity. Increasing the Reynolds number for an
of 2.91 resulted in the development of a dual leading-edge vortex (LEV) structure, however increasing
at a fixed Reynolds number generated the same flow structures. This result shows that the effects of Reynolds number and
are linked. We present an alternative scaling using wing span as the characteristic length to decouple the effects of Reynolds number from those of
. This results in a span-based Reynolds number, which can be used to independently describe the development of the LEV. Indeed, universal behaviour was found for various parameters using this scaling. The effect of
on the vortex structures and aerodynamic forces was then assessed at different span-based Reynolds numbers. Scaling the flow using the wing span was found to apply when a strong spanwise velocity is present on the leeward side of the wing and therefore may prove to be useful for similar studies involving flapping or rotating wings at high angles of attack.
Aspects of the turbulent wind environment Micro Air Vehicles (MAVs) experience when flying outdoors were replicated in a large wind tunnel. An overview of the facility, instrumentation and initial flight tests is given. Piloting inputs and aircraft accelerations were recorded on fixed and rotary wing MAVs and for some tests, measurements of the approach flow (u,v,w sampled at 1,250Hz at four laterally disposed upstream locations) were made. The piloting aim was to hold straight and level flight in the 12m wide × 4m high × ~50m long test section, while flying in a range of turbulent conditions. The Cooper-Harper rating system showed that a rotary craft was less sensitive to the effects of turbulence compared to the fixed wing craft and that while the fixed wing aircraft was relatively easy to fly in smooth air, it became extremely difficult to fly under high turbulence conditions. The rotary craft, while more difficult to fly per. se., did not become significantly harder to fly in relatively high turbulence levels. However the rotary craft had a higher mass and MOI than the fixed wing craft and further work is planned to understand the effects of these differences.
To better determine the optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection, we evaluated the utility of a novel combination antibiogram. Although the combination antibiogram allowed modest fine-tuning of choices for dual antibiotic therapy, selections based on the 2 antibiograms did not differ substantively. Drug combinations with the broadest coverage were consistently composed of an aminoglycoside and a β-lactam.
Two- and three-dimensional instabilities of the two-dimensional symmetric flow generated by a circular cylinder oscillating with simple harmonic motion in quiescent fluid, or, alternatively, by oscillatory flow past a stationary cylinder at low Keulegan-Carpenter and Stokes numbers are investigated via Floquet analysis and direct numerical simulation. Previous experimental visualization has found that the flows produced at low amplitudes and frequencies of motion can be grouped by their visual characteristics into a number of distinct regimes. At low values of Keulegan-Carpenter and Stokes numbers, the flow is two-dimensional and has a reflection symmetry about the axis of oscillation, in addition to a pair of spatio-temporal symmetries. This study isolates and classifies the symmetry-breaking instabilities from these two-dimensional basic states as functions of these control parameters. It is found that while the initial bifurcations produced by increasing the parameters can be to three-dimensional flows, much of the behaviour can be explained in terms of two-dimensional symmetry-breaking instabilities. These have two primary manifestations: at low Stokes numbers, the instability is synchronous with the imposed oscillation, and gives rise to a boomerang-shaped mode, while at higher Stokes numbers, the instability is quasi-periodic, with a well-defined second period, which becomes infinite as Stokes numbers are reduced along the marginal stability boundary, ‘freezing’ the quasi-periodic mode into a synchronous one. These two-dimensional modes are, with further small increase in control parameter, unstable to three-dimensional secondary instabilities, and these are the flows which have been reported in previous experimental studies. In contrast, the mode first reported by Honji (J. Fluid Mech. vol. 107, 1981, p. 509), which arises at high Stokes numbers, and lower Keulegan-Carpenter numbers than the two-dimensional quasi-periodic mode, has a three-dimensional primary instability arising directly from the symmetrical two-dimensional basic state.
The meat palatability, water-holding capacity, colour and shear force values of 32 Boer goat (BG) kids and 32 South African Mutton Merino (MM) lambs were investigated. Two pelleted diets (offered to 16 animals per species) with either a low (LE, 9·9 MJ/kg dry matter (DM)) or a high (HE, 12·1 MJ/kg DM) metabolizable energy level were given to the animals for either 28 or 56 days. Thereafter the animals were slaughtered, the meat cooked and presented to a trained sensory panel. Organoleptically, a difference between goat and lamb was noted. Each one had a specific species flavour, which was not influenced by energy level of the diet. BG meat was perceived to be stringier than that of the MM, but there was no significant difference in Warner-Bratzler shear force values. Tenderness declined with age in both species and there was also a tendency for goat meat to be less juicy than lamb. Chevon had a more pronounced after-taste than lamb. No objective difference could be distinguished between the colour of the cooked goat and lamb, but there was a tendency for fresh lamb to have a higher a*-value (redness) than goat. Although diet did not influence drip loss, drip loss increased with an increase in slaughter age. Only after 56 days did the m. semimembranosus of MM have a significantly higher drip loss than that of BG (LE: 4·84 v. 3·43%; HE: 4·72 v. 3·23%). In the m. semimembranosus of both species cooking loss increased with an increase in slaughter age. It can be concluded that goat meat compares favourably with lamb in terms of water-holding capacity, colour and shear force values. If goats are finished in the feedlot, it can be done on a LE diet, since diet does not influences any of the mentioned characteristics. This may render a direct economic advantage for BG feedlot finishing.
Carcass measurements, commercial cuts and chemical composition of the meat of 32 Boer goat (BG) kids and 32 South African Mutton Merino (MM) lambs were investigated. Two pelleted diets (offered to 16 animals per species) with either a low (LE, 9·9 MJ/kg dry matter (DM)) or a high (HE, 121 MJ/kg DM) metabolizable energy level were offered, ad libitum, for either 28 or 56 days. Thereafter the animals were slaughtered and the carcasses dissected into South African commercial cuts. The 8-9-10-rib cut of each carcass was dissected and used for chemical analysis. MM had heavier carcasses (LE: 19·87w. 15·28 kg; HE: 2401 v 17·05 kg), and proportionally heavier ribs and buttocks than BG and therefore one can expect higher prices for sheep carcasses than for those of goats. BG had significantly more moisture and protein and lower fat and energy values than MM. DM, fat and energy values increased with an increase in slaughter age in both species. BG had significantly higher concentrations of 11 of the 18 measured essential amino acids in their 8-9-10-rib cuts than the MM. Goat carcasses had higher Ca, K, Mg, Na and P levels than sheep carcasses, regardless of the diet offered. BG had a lower carcass cholesterol content than lamb (66·77 v. 99·28 mg/100 g, respectively). Palmitic (C16: 0), stearic (C18: 0) and oleic (C18: 1n9) acids comprised the greatest proportions of the fatty acids in the 8-9-10-rib cut. On both diets there was a significantly higher saturated to unsaturated (SFA: UFA) fatty acid ratio in lamb than in goat meat (LE: 0·30 v 0·845; HE 1·407 v. 0·892). It can be concluded that chemically the meat from young feedlot goats is not inferior to that of lamb, and since it has a higher protein percentage and lower fat, cholesterol and SFA it can be considered as a healthy food commodity. Since diet had little or no significant influence on the carcass weight distribution or chemical composition of the goats, BGs can be finished on a LE-diet in the feedlot. This may decrease the food cost significantly.
The passive and active electrical properties of left ventricular myocardium were measured, using conducted action potentials and current clamp of isolated myocytes. The objective was to quantify changes of intracellular resistivity, Ri, during hypertrophic growth and the simultaneous imposition of cellular hypoxia. Ri was estimated from the time course of the rising phase of a conducted action potential using a solution of the two-dimensional cable equation. The thoracic aorta of guinea-pigs was constricted to induce left ventricular hypertrophy (LVH) and myocardium used 50 and 150 days post-operation. Conduction velocity increased in the earlier stage of LVH and declined in the later stage, compared with age-matched controls. Hypoxia reduced conduction velocity in all experimental groups. Ri increased only in the later stage of hypertrophy (253 ± 39 [Omega] cm to 544 ± 130 [Omega] cm) and was additionally increased by hypoxia in all groups (e.g. control myocardium 252 ± 39 [Omega] cm to 506 ± 170 [Omega] cm). The magnitude of the increase of Ri in hypertrophied, hypoxic myocardium can create conditions required to generate re-entrant arrhythmias.
Chemical analysis on a microscopic scale was performed on a TiN particle sample on silicon and on two patterned samples using a synchrotron source scanning photoemission microscope. For all the experiments, we exploit the ability, developed in our experimental system, to reach specific locations on the wafer and analyze the local chemical state.