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A model devised by Thorpe & Li (J. Fluid Mech., vol. 758, 2014, pp. 94–120) that predicts the conditions in which stationary turbulent hydraulic jumps can occur in the flow of a continuously stratified layer over a horizontal rigid bottom is applied to, and its results compared with, observations made at several locations in the ocean. The model identifies two positions in the Samoan Passage at which hydraulic jumps should occur and where changes in the structure of the flow are indeed observed. The model predicts the amplitude of changes and the observed mode 2 form of the transitions. The predicted dissipation of turbulent kinetic energy is also consistent with observations. One location provides a particularly well-defined example of a persistent hydraulic jump. It takes the form of a 390 m thick and 3.7 km long mixing layer with frequent density inversions separated from the seabed by some 200 m of relatively rapidly moving dense water, thus revealing the previously unknown structure of an internal hydraulic jump in the deep ocean. Predictions in the Red Sea Outflow in the Gulf of Aden are relatively uncertain. Available data, and the model predictions, do not provide strong support for the existence of hydraulic jumps. In the Mediterranean Outflow, however, both model and data indicate the presence of a hydraulic jump.
Some data suggest that older adults with anxiety disorders do not respond as well to treatment as do younger adults.
We examined age differences in outcomes from the Coordinated Anxiety Learning and Management (CALM) study, an effectiveness trial comparing usual care to a computer-assisted collaborative care intervention for primary care patients with panic disorder, generalised anxiety disorder, post-traumatic stress disorder (PTSD), and/or social anxiety disorder. This is the first study to examine the efficacy of a collaborative care intervention in a sample that included both younger and older adults with anxiety disorders. We hypothesised that older adults would show a poorer response to the intervention than younger adults.
We examined findings for the overall sample, as well as within each diagnostic category (clinicaltrials.gov identifier: NCT00347269).
The CALM intervention was more effective than usual care among younger adults overall and for those with generalised anxiety disorder, panic disorder and social anxiety disorder. Among older adults, the intervention was effective overall and for those with social anxiety disorder and PTSD but not for those with panic disorder or generalised anxiety disorder. The effects of the intervention also appeared to erode by the 18-month follow-up, and there were no significant effects on remission among the older adults.
These results are consistent with the findings of other investigators suggesting that medications and psychotherapy for anxiety disorders may not be as effective for older individuals as they are for younger people.
To determine if children aged 1–6 years from non-Western immigrant families have lower serum 25-hydroxyvitamin D (25(OH)D) levels than children from Western-born families and examine which factors influence this relationship.
Healthy children (n 1540) recruited through the TARGet Kids! practice-based research network. Serum 25(OH)D concentrations of non-Western immigrants were compared with those of children from Western-born families. Children from non-Western immigrant families were defined as those born, or their parents were born, outside a Western country. Univariate and multiple linear regression analyses were used to identify factors which might influence this relationship.
Median age was 36 months, 51 % were male, 86 % had ‘light’ skin pigmentation, 55 % took vitamin D supplements, mean cow's milk intake was 1·8 cups/d and 27 % were non-Western immigrants. Median serum 25(OH)D concentration was 83 nmol/l, with 5 % having 25(OH)D < 50 nmol/l. Univariable analysis revealed that non-Western immigrant children had serum 25(OH)D lower by 4 (95 % CI 1·3, 8·0) nmol/l (P = 0·006) and increased odds of 25(OH)D < 50 nmol/l (OR = 1·9; 95 % CI 1·3, 2·9). After adjustment for known vitamin D determinants the observed difference attenuated to 0·04 (95 % CI −4·8, 4·8) nmol/l (P = 0·99), with higher cow's milk intake (P < 0·0001), vitamin D supplementation (P < 0·0001), summer season (P = 0·008) and increased age (P = 0·04) being statistically significant covariates. Vitamin D supplementation was the strongest explanatory factor of the observed difference.
There is an association between non-Western immigration and lower 25(OH)D in early childhood. This difference appears related to known vitamin D determinants, primarily vitamin D supplementation, representing opportunities for intervention.
Our previous work suggests that stressors that impact placental vascular growth result in a deformed chorionic surface shape, which reflects an abnormal placental three-dimensional shape. We propose to use variability of placental disk thickness as a reflector of deviations in placental vascular growth at the finer level of the fetal stems. We hypothesize that increased variability of thickness is associated with abnormal chorionic surface shape, but will be a predictor of reduced placental functional efficiency (smaller baby for a given placental weight) independent of shape. These measures may shed light on the mechanisms linking placental growth to risk of adult disease. The sample was drawn from the Pregnancy, Infection and Nutrition Study. In all, 94.6% of the cohort consented to placental examination. Of the 1023 delivered at term, those previously sectioned by the Pathology Department were excluded, leaving 587 (57%) cases with intact placentas that were sliced and photographed. The chorionic surface shape and the shape of a central randomly oriented placental slice were analyzed and measures were compared using correlation. Lower mean placental disk thickness and more variable disk thickness were each strongly and significantly correlated with deformed chorionic plate shapes. More variable disk thickness was strongly correlated with reduced placental efficiency independent of abnormal chorionic surface shape. Variability of placental disk thickness, simple to measure in a single randomly oriented central slice, may be an easily acquired measure that is an independent indicator of lowered placental efficiency, which may in turn program the infant and result in increased risk for development of adult diseases.
Posttraumatic stress disorder (PTSD) has been associated with neuropsychological impairments across multiple domains, but consensus regarding the cognitive profile of PTSD has not been reached. In this study of women with PTSD related to intimate partner violence (n = 55) and healthy, demographically similar comparison participants (NCs; n = 20), we attempted to control for many potential confounds in PTSD samples. All participants were assessed with a comprehensive neuropsychological battery emphasizing executive functioning, including inhibition, switching, and abstraction. NCs outperformed PTSD participants on most neuropsychological measures, but the differences were significant only on speeded tasks (with and without executive functioning components). The PTSD group’s mean performance was within the average range on all neuropsychological tests. Within the PTSD group, more severe PTSD symptoms were associated with slower processing speed, and more severe dissociative symptoms were associated with poorer reasoning performance. These results suggest that women with PTSD related to intimate partner violence demonstrate slower than normal processing speed, which is associated with the severity of psychiatric symptoms. We speculate that the cognitive slowing seen in PTSD may be attributable to reduced attention due to a need to allocate resources to cope with psychological distress or unpleasant internal experiences. (JINS, 2009, 15, 879–887.)
In tests of 40 samples of milk from the supply of the city of Edinburgh:
(1) The bacterial content was, on the average, high but not abnormally so when compared with that of the milk supply of other cities. It ranged from 20,000 to 29,000,000 per c.c.
(2) The results of the reductase test corresponded well with the bacterial counts and the test is recommended for obtaining a good rough idea of the bacterial numbers present, where results are required in a short time.
(3) About half of the samples contained lactose-fermenting organisms in unduly high numbers; this is attributed chiefly to the lack of attention to cleanliness in production.
(4) The value of the fermentation test for speedily indicating the nature of bacterial contamination is pointed out. In a general way the test corroborated the results of counts of the lactose fermenters and indicated that a number of the samples, which did not produce blown curds, contained large numbers of undesirable organisms.
(5) Taken as a whole, the results seem to indicate not so much particularly high contamination as contamination of a very undesirable nature. They point to the necessity of educating the producer and distributor in the principles underlying the production of clean milk and emphasise the importance of proper control of the industry from this point of view.
The stability of flows cascading down slopes as dense inclined plumes is examined, with particular reference to flows observed in Lake Geneva during winter periods of severe cooling. A previous conjecture by Turner that the flow may be in a state of marginal stability is confirmed: the observed mean velocity and density profiles are unstable to Kelvin–Helmholtz instability, but only marginally so; the growth rates of the most unstable small disturbances to the cascading flow in Lake Geneva are small, with e-folding periods of about 2 h. A reduction in the maximum velocity by about 20% is required to stabilize the flow.
The possibility that stationary hydraulic jumps may occur in the observed flow is also considered. Several plausible flow states downstream of transitions are examined, allowing for mixing and density changes to occur, ranging from one that preserves the shape of the density and velocity profiles to one in which, as a consequence of mixing, the velocity and density become uniform in depth within the cascading flow. Neither of these extreme states is found to conserve the fluxes of volume, mass and momentum through a transition in which the energy flux does not increase, and to be unique or ‘stable’ in the sense that no further transition is possible to a similar flow state without more entrainment. Stable transitions to intermediate downstream flows that conserve flow properties and reduce energy flux are, however, found, although the smallest value of the flow parameter, Fr≡ Umax2/gΔ h (where Umax is the maximum flow speed, g is the acceleration due to gravity, Δ is a fractional density difference within the flow and h is the flow thickness) at which transitions may occur is only slightly less than that of the cascading flow in Lake Geneva. In this sense, the observed flow is marginally unstable to a finite-amplitude transition or hydraulic jump. Velocity and density profiles of possible flows downstream of a transition are found. The amplitudes of possible transitions and the flux of water entrained from the ambient overlying water mass are limited to narrow ranges.
Red Maasai and Dorper sheep were evaluated for their resistance to gastro-intestinal (GI) nematode parasites (predominantly Haemonchus contortus), productivity and productive efficiency (assessed on a metabolizable energy basis) in experiments undertaken at the Kenyan coast (sub-humid environment) and the Kenya highlands (semi-arid environment). In both ewes and lambs there were few significant genotype by environment (G X E) interactions for either resistance (assessed by faecal egg counts-FEC) or resilience (assessed by blood packed red cell volume-PCV) to GI nematodes. Red Maasai sheep were consistently more resistant (low FEC) and more resilient (high PCV) than Dorper sheep. However, there were significant G X £ interactions for ewe reproductive performance and for ewe and lamb mortality rates and live weights. These interactions were due to very poor performance of the Dorper compared to the Red Maasai in the sub-humid coastal environment and to the much improved performance of the Dorper in the semi-arid environment. When these component traits were combined into estimates of flock productivity and productive efficiency there were highly significant GXE interactions with the Red Maasai sheep being considerably more efficient than Dorper sheep in the sub-humid environment, while in the semi-arid environment there was a negligible breed difference in productive efficiency. The results are discussed in terms of breeding strategies for smallholder farmers and pastoralists managing sheep in low-input systems in sub-humid and semi-arid environments.
The diversification of the lizard genus Anolis on Caribbean islands surely represents one of the best-studied cases of adaptive radiation in evolutionary biology. Over the course of the past four decades, researchers have studied almost every aspect of anole evolutionary ecology. These include systematics; community, physiological, and behavioral ecology; functional morphology; ethology; and demography. Studies have been conducted in the laboratory and in the field, and have included basic natural history, geographic and temporal comparisons of populations, and a wide variety of experimental approaches to the study of phenotypic plasticity, ethology, ecology, and evolution [recent reviews include Losos (1994) and Roughgarden (1995)]. The result is an unusually broad and detailed understanding of the factors that promote and sustain evolutionary diversification and species coexistence.
Speciation and adaptation in anoles
Two conclusions from the current body of work are obvious. First, the genus Anolis has experienced extensive speciation. With more than 400 described species, and more being described every year, Anolis is the largest amniote genus, exceeded among tetrapods only by the potentially para- or polyphyletic frog genus Eleutherodactylus. The nearly 150 Caribbean species are descendants from as few as two initial colonizing species from the mainland (Jackman et al. 1997). Hence, the diversity of Caribbean species results almost entirely from speciation, rather than from repeated colonization.
Second, adaptive diversification has been rampant. Within assemblages of anoles, species are clearly specialized to occupy different niches. Physiological and functional studies have revealed evidence for adaptation to particular microclimatic and structural habitats. Moreover, intraspecific comparisons indicate that populations adapt to their particular environmental conditions (reviewed in Malhotra and Thorpe 2000).
We hypothesised that the observed acceleration in the kinetics of exercise on-transient oxygen uptake (V˙O2) of five older humans (77 ± 7 years (mean ± S.D.) following 9 weeks of single-leg endurance exercise training was due to adaptations at the level of the muscle cell. Prior to, and following training, subjects performed constant-load single-limb knee extension exercise. Following training V˙O2 kinetics (phase 2, τ) were accelerated in the trained leg (week 0, 92 ± 44 s; week 9, 48 ± 22 s) and unchanged in the untrained leg (week 0, 104 ± 43 s; week 9, 126 ± 35 s). The kinetics of mean blood velocity in the femoral artery were faster than the kinetics of V˙O2, but were unchanged in both the trained (week 0, 19 ± 10 s; week 9, 26 ± 11 s) and untrained leg (week 0, 20 ± 18 s; week 9, 18 ± 10 s). Maximal citrate synthase activity, measured from biopsies of the vastus lateralis muscle, increased (P < 0.05) in the trained leg (week 0, 6.7 ± 2.0 µmol (g wet wt)-1 min-1; week 9, 11.4 ± 3.6 µmol (g wet wt)-1 min-1) but was unchanged in the untrained leg (week 0, 5.9 ± 0.5 µmol (g wet wt)-1 min-1; week 9, 7.9 ± 1.9 µmol (g wet wt)-1 min-1). These data suggest that the acceleration of V˙O2 kinetics was due to an improved rate of O2 utilisation by the muscle, but was not a result of increased O2 delivery. Experimental Physiology (2001) 86.5, 659-665.
Burow’s solution (13 per cent aluminium acetate) has been found to inhibit in vitro the growth of most commonly occurring bacteria found in the discharging ear. An in vitro study has shown that the minimum inhibitory concentration of Burow’s solution for these organisms lies between a 1:80 and a 1:160 dilution. This paper reports on a clinical trial that incorporated 67 discharging ears to establish the most effective strength of aluminium acetate solution. There was no statistical difference in the effectiveness of full strength Burow’s solution compared to 3.25 per cent aluminium acetate solution (a quarter strength Burow’s solution). Response rates of 80.8 per cent and 75 per cent respectively following a two-week treatment period were achieved using these two solutions. A 1.3 per cent aluminium acetate solution (1/10 strength Burow’s solution) was found to be markedly inferior. Bacteriological and audiological profiles were recorded for each patient.
The object of these experiments was to study the pathogenesis and
kinetics of Theileria annulata infection in the efferent
lymph of the draining lymph nodes of calves. Efferent lymphatics of calves
were cannulated prior to infection with T.
annulata sporozoite or an allogeneic schizont cell line. Potentially
lethal sporozoite challenge induced cell shut-down from
days 4–6 and then a massive increase in output of blasting cells
(both infected and non-infected) in the efferent lymph.
The rate of lymph flow and total cell output increased to 5 to 10-fold
from day 6 onwards. Sporozoites were never isolated
from the efferent lymph. However, large numbers of parasite-infected cells
were seen in efferent lymph from the sixth day
of infection. The animals inoculated with an allogeneic T. annulata-infected
cell line exhibited only a small increase in flow
rate and cell output. Parasite-infected cells of recipient origin were
seen in efferent lymph from day 11 onwards. However,
cells of donor origin were never isolated either from efferent lymph or
peripheral blood. Thus the parasite transferred from
the inoculated donor cell line to the cells of the recipient before schizonts
appeared in efferent lymph.
This double-blind, randomized trial compared the onset of sedation with two patient-controlled sedation regimens, allowing a maximum of 16 or 25 mg min−1 propofol. Forty fit young patients presenting for elective surgery were asked to try to put themselves to sleep using the system. Onset times of sedative effect, slurred speech and amnesia were recorded. All patients achieved satisfactory sedation, and none became oversedated. Patients receiving 16 mg min−1 propofol were not reliably sedated within 5 min and took significantly longer to develop slurred speech and amnesia (P< 0.01 for both). We conclude that this maximum infusion rate does not produce amnesia or sedation rapidly enough to be clinically useful. A maximum infusion rate of 25 mg min−1 allowed rapid sedation in all patients without oversedation and may be an acceptable compromise between efficacy and safety.
In this paper we find the norm of powers of the indefinite integral
operator V, acting on L2(0, 1).
This answers a question raised by Halmos, and supplements some recent
results of Manakov in .
Using results of Stepanov in , we show that the
operator norm of Vn is asymptotically equal
Hilbert–Schmidt norm as n→∞.