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Coordinated laboratory experiments and computational simulations are conducted that explore the collective vertical migration of a swarm of inertial swimmers through a stably stratified density interface. Values of the governing parameters such as the swimmer- and swarm-scale Reynolds numbers, the Richardson number, as well as the animal number density in the swarm closely match each other in the simulations and experiments. In addition to intense mixing at the swimmer scale, the experiments and simulations demonstrate that the hydrodynamic interaction of the individual swimmers produces a spatially coherent source of thrust that results in the formation of a swarm-scale jet in the direction opposite to the migration. The jet velocity is seen to increase monotonically with the animal number density, at a sublinear rate. For steadily moving dilute swarms, the jet velocity is well predicted by a simple analytical model that assumes spatially uniform jet and swimmer velocities. Experimental measurements demonstrate effective diffusivity values up to three orders of magnitude larger than the molecular value. Numerical results are consistent with these observations, although they employ a larger molecular diffusivity and, hence, yield a lower ratio. The effective diffusivity is seen to increase linearly with the volume fraction of the swimmers. A continuum model is proposed for the generation of the swarm-scale jet, based on an idealization of the swarm as a self-propelled porous sphere. This model suggests that large swarms generate most of their mixing through the coherent swarm-scale jet, rather than by processes at the scale of individual swimmers.
This paper examines the velocity distribution function and cyclotron resonance conditions for a beam of electrons moving in a magnetic field which gradually changes with time. A spatial gradient of magnetic field is known to result in an unstable horseshoe distribution of electrons. The field gradient in time adds additional effects due to an induced electric field. The resultant anisotropic velocity distribution function, which we call a Luvdisk distribution, has some distinctive properties when compared to the horseshoe. Fitting the cyclotron resonance condition circle shows that the frequency of the resultant emission is under the local cyclotron frequency. While the spatial gradient results in the emission coming almost perpendicularly to the field, the direction of the radiation under a time-changing field has more variability. The Luvdisk distribution also arises when the magnetic field has a gradient both in space and time. The beam can be unstable if those gradients are added or subtracted from each other (if the gradients are of equal or different sign), which occurs even when the total change of magnetic field is negative. While the frequency of the emission is related to the final magnetic field value, its direction is indicative of the field’s history which produced the instability.
Folic acid (FA) supplementation is recommended in the periconceptional period, for the prevention of neural tube defects. Limited data are available on the folate status of New Zealand (NZ) pregnant women and its association with FA supplementation intake. Objectives were to examine the relationship between plasma folate (PF) and reported FA supplement use at 15 weeks’ gestation and to explore socio-demographic and lifestyle factors associated with PF. We used data and blood samples from NZ participants of the Screening for Pregnancy Endpoints cohort study. Healthy nulliparous women with singleton pregnancy (n 1921) were interviewed and blood samples collected. PF was analysed via microbiological assay. Of the participants, 73 % reported taking an FA supplement at 15 weeks’ gestation – of these, 79 % were taking FA as part of/alongside a multivitamin supplement. Of FA supplement users, 56 % reported consuming a daily dose of ≥800 μg; 39 % reported taking less than 400 µg/d. Mean PF was significantly higher in women reporting FA supplementation (54·6 (se 1·5) nmol/l) v. no FA supplementation (35·1 (se 1·6) nmol/l) (P<0·0001). Reported daily FA supplement dose and PF were significantly positively correlated (r 0·41; P<0·05). Younger maternal age, Pacific and Maori ethnicity and obesity were negatively associated with PF levels; vegetarianism was positively associated with PF. Reported FA supplement dose was significantly associated with PF after adjustment for socio-demographic, lifestyle confounders and multivitamin intake. The relationship observed between FA supplementation and PF demonstrates that self-reported intake is a reliable proxy for FA supplement use in this study population.
To examine the relationship between protein intake and the risk of incident premenstrual syndrome (PMS).
Nested case–control study. FFQ were completed every 4 years during follow-up. Our main analysis assessed protein intake 2–4 years before PMS diagnosis (for cases) or reference year (for controls). Baseline (1991) protein intake was also assessed.
Nurses’ Health Study II (NHS2), a large prospective cohort study of registered female nurses in the USA.
Participants were premenopausal women between the ages of 27 and 44 years (mean: 34 years), without diagnosis of PMS at baseline, without a history of cancer, endometriosis, infertility, irregular menstrual cycles or hysterectomy. Incident cases of PMS (n 1234) were identified by self-reported diagnosis during 14 years of follow-up and validated by questionnaire. Controls (n 2426) were women who did not report a diagnosis of PMS during follow-up and confirmed experiencing minimal premenstrual symptoms.
In logistic regression models adjusting for smoking, BMI, B-vitamins and other factors, total protein intake was not associated with PMS development. For example, the OR for women with the highest intake of total protein 2–4 years before their reference year (median: 103·6 g/d) v. those with the lowest (median: 66·6 g/d) was 0·94 (95 % CI 0·70, 1·27). Additionally, intakes of specific protein sources and amino acids were not associated with PMS. Furthermore, results substituting carbohydrates and fats for protein were also null.
Overall, protein consumption was not associated with risk of developing PMS.
In addition to being associated with a higher risk of complications during pregnancy, twinning may also be a proxy for altered hormonal exposure for mothers and twin offspring, with implications for their health later in life. We compared maternal and fetal steroid hormone and insulin-like growth factor concentrations between singleton (n=62) and twin (n=41) pregnancies. Maternal concentrations of androgens, estrogens, insulin-like growth factor (IGF)-1, IGF-binding protein (BP)-3 and prolactin were quantified during the third trimester and at delivery, as well as in the fetal circulation at birth. Geometric means accounting for gestational age were calculated for hormone concentrations and compared between matched twin and singleton pregnancies. Most maternal hormone concentrations were modestly higher in twin than in singleton pregnancies in the third trimester (ranging from 8.3% for IGF-1 to 17.1% for estradiol) and at delivery (ranging from 11.1% for IGFBP-3 to 15.2% for estriol). Cord serum hormones were generally similar in twin and singleton pregnancies, except for IGFBP-3, which was 200% lower in twins. The modest differences in maternal hormones in late gestation seem unlikely to explain alterations in hormonally related disease risk in mothers of twins compared with singletons. The large deficit of IGFBP-3 in the fetal circulation of twins at birth may allow for sufficient concentrations of IGF-2 for growth and development in an environment of shared nutritional resources.
Approximately 8–20 % of reproductive-aged women experience premenstrual syndrome (PMS), substantially impacting quality of life. Women with PMS are encouraged to reduce fat intake to alleviate symptoms; however, its role in PMS development is unclear. We evaluated the association between dietary fat intake and PMS development among a subset of the prospective Nurses’ Health Study II cohort. We compared 1257 women reporting clinician-diagnosed PMS, confirmed by premenstrual symptom questionnaire and 2463 matched controls with no or minimal premenstrual symptoms. Intakes of total fat, subtypes and fatty acids were assessed via FFQ. After adjustment for age, BMI, smoking, Ca and other factors, intakes of total fat, MUFA, PUFA and trans-fat measured 2–4 years before were not associated with PMS. High SFA intake was associated with lower PMS risk (relative risk (RR) quintile 5 (median=28·1 g/d) v. quintile 1 (median=15·1 g/d)=0·75; 95 % CI 0·58, 0·98; Ptrend=0·07). This association was largely attributable to stearic acid intake, with women in the highest quintile (median=7·4 g/d) having a RR of 0·75 v. those with the lowest intake (median=3·7 g/d) (95 % CI 0·57, 0·97; Ptrend=0·03). Individual PUFA and MUFA, including n-3 fatty acids, were not associated with risk. Overall, fat intake was not associated with higher PMS risk. High intake of stearic acid may be associated with a lower risk of developing PMS. Additional prospective research is needed to confirm this finding.
Recent issues of Antiquity have seen much discussion on the topic of Carthaginian infant sacrifice: was it a Graeco-Roman fiction or did it really happen? There are strongly held opinions on both sides of the argument, with much resting on the age profile of the children interred at the cemetery known as the Carthage Tophet. Here, the authors respond to claims by Smith et al. (2011, 2013) that their ageing of the infants and children was incorrect, and so also by extension was their interpretation that not all interments at the Tophet were the result of sacrifice.
We present the KMOS (K-band Multi-Object Spectrograph) Cluster and VIRIAL (VLT IRIFU Absorption Line) Guaranteed Time Observation (GTO) programs. KMOS provides 24 arms each feeding an integral field unit (14×14 spaxels of 0.2″ pixels) for IZ, YJ, H and K band near infrared (NIR) medium resolution spectroscopy (R ∼ 3500). Targets are selected from a 7.2′ diameter patrol field. Ultra-deep spectroscopy of ∼ 80 early-type cluster galaxies (∼ 20hr on source) and ∼ 200 (∼ 10hr on source) early-type field galaxies at 1 < z < 2 will dramatically improve the situation at z > 1 for which measurements of stellar velocity dispersions and absorption indices are limited to a few, often relatively young passively evolving galaxies (e.g. Bezanson 2013). In ESO Periods P92 and P93, 15 nights worth of data has been collected for KMOS-Clusters and 6 nights for VIRIAL: this will be supplemented with more data in upcoming semesters. All galaxies have multiband HST imaging including existing or upcoming WFC3 IR imaging, providing stellar mass maps and sizes. Combined with our dispersion measurements, this will allow us to examine the fundamental plane and the dynamical mass of a large sample of z > 1 galaxies for the first time, for both cluster and field galaxies.
KMOS is a cryogenic infrared spectrograph fed by twentyfour deployable integral field units that patrol a 7.2 arcminute diameter field of view at the Nasmyth focus of the ESO VLT. It is well suited to the study of galaxy clusters at 1 < z < 2 where the well understood features in the restframe V-band are shifted into the KMOS spectral bands. Coupled with HST imagining, KMOS offers a window on the critical epoch for galaxy evolution, 7-10 Gyrs ago, when the key properties of cluster galaxies were established. We aim to investigate the size, mass, morphology and star formation history of galaxies in the clusters. Here we describe the instrument, discuss the status of the observations and report some preliminary results.
To evaluate the impact of a mandatory bread fortification programme on estimated iodine intakes of childbearing women and to describe the extent to which uptake of a maternal iodine supplement recommendation is associated with sociodemographic characteristics.
A postpartum survey was conducted using a self-administered questionnaire. Details on pre- and post-conceptional supplement use, bread intake, iodized salt use and maternal sociodemographic and obstetric characteristics were obtained.
Eleven maternity wards and hospitals located across New Zealand.
Seven hundred and twenty-three postpartum New Zealand women.
Mean iodine intake from fortified bread was 37 μg/d prior to conception. Younger women, women with higher parity, single women and those with unplanned pregnancies were less likely to meet the pregnancy Estimated Average Requirement (EAR) for iodine (all P ≤ 0·022). Although not statistically significant for all months of pregnancy, women with less education and income were less likely to meet the EAR (P ≤ 0·11 and P ≤ 0·2 for all months, respectively) and indigenous Māori women and Pacific women were less likely than New Zealand Europeans to meet the EAR (P ≤ 0·17 and P ≤ 0·051 for all months, respectively). During pregnancy, iodine-containing supplement uptake at the recommended level (150 μg/d) was non-uniform across sociodemographic subgroups, with the most disadvantaged women benefiting the least from this public health policy.
The disparities in supplement uptake noted here highlight the need for prioritizing further efforts towards universal salt iodization, such as the mandatory fortification of additional processed foods with iodized salt.
During strombolian eruptions, large bubbles of exsolved magmatic gas, with sizes of meters or more, intermittently burst at the magma surface, spraying magma clots over distances of tens to hundreds of meters. This style of activity results from low magma viscosities allowing gas bubbles to move through the liquid magma phase. Relatively small bubbles rise and coalesce into bubbles with diameters similar to that of the conduit, at which point they are called gas slugs. This coalescence is responsible for converting the continuous degassing processes at depth into the observed intermittent surface activity, and may be controlled by the decompression expansion of the bubbles or by portions of non-vertical conduit geometry. Models of strombolian systems cover the bubble coalescence phase (slug generation), the slug ascent, and finally slug burst and the ejection of pyroclasts. A wide range of geophysical measurements, notably from Stromboli and Erebus volcanoes, are available to test these subsurface models. Nevertheless, key questions, such as the degree to which the activity is controlled by the geometry of the conduit, remain.
At volcanoes with relatively low-viscosity magmas such as basalt and basaltic andesite, large bubbles (with sizes of meters or greater) of exsolved gas can ascend rapidly through the melt and burst energetically at the surface, producing sprays of molten pyroclasts (Fig. 6.1). This type of intermittent explosion, in which a limited amount of magma is erupted with a relatively significant mass of gas, is known as “strombolian” after the characteristic activity at Stromboli volcano, where several such events usually occur every hour.
The global carbon (C) cycle can be characterized in multiple ways. In Chapter 2, C pools, fluxes, and mechanisms controlling the size and rates of pools and fluxes of C are reviewed as a whole. In this chapter, the primary concern is with annual net exchanges of C between the atmosphere and three other major C pools – land, oceans, and fossil fuels – with an emphasis on the role that land use and land-use change have in adding C to or removing it from the atmosphere. The net exchanges are important because they determine the rate at which carbon dioxide (CO2) accumulates in the atmosphere and, hence, the rate and extent of climate change.
The dominant feature of the annual net global emissions of C from land use and land-use change is the gradually increasing trend over the past 155 years (1850 to 2005; Figure 3.1) and probably much longer (Kaplan, Krumhardt, and Zimmermann 2009). This trend, however, is misleading for at least two reasons. First, the trend is not representative of any specific geographic region; because the trend is global, it obscures regional trends. The gradually increasing trend is the result of recently decreasing net emissions and increasing sinks in developed countries (in temperate and boreal zones) offsetting more rapidly increasing net emissions from developing countries in the tropics (Figure 3.2). Second, the net emissions hide the much larger gross sources and sinks of C from land use and land-use change (Figure 3.3). More C is emitted to and removed from the atmosphere each year as a direct result of human activity than is revealed by estimates of the net flux.
Writing about the ‘Tophet’, a children's cemetery in Carthage, Smith et al. argued in these pages that the age distribution of the children peaks at 1–1.49 months, supplying “another link in the chain of evidence—funerary practices, texts, iconography—that supports the interpretation of the Phoenician Tophets as ritual sites set aside for infant sacrifice” (2011: 871). In this they had challenged Jeffrey Schwartz and colleagues, who previously argued (2010) that “skeletal remains from Punic Carthage do not support systematic sacrifice of infants”. Here Schwartz et al. restate their position for Antiquity readers, showing that the verdict on the Phoenician practice of child sacrifice is, at best, not proven.
Public health recommendations do not distinguish between vitamin D2 and vitamin D3, yet disagreement exists on whether these two forms should be considered equivalent. The objective of the present study was to evaluate the effect of a daily physiological dose of vitamin D2 or vitamin D3 on 25-hydroxyvitamin D (25(OH)D) status over the winter months in healthy adults living in Dunedin, New Zealand (latitude 46°S). Participants aged 18–50 years were randomly assigned to 25 μg (1000 IU) vitamin D3 (n 32), 25 μg (1000 IU) vitamin D2 (n 31) or placebo (n 32) daily for 25 weeks beginning at the end of summer. A per-protocol approach, which included ≥ 90 % supplement compliance, was used for all analyses. Serum 25-hydroxyvitamin D3 (25(OH)D3), 25-hydroxyvitamin D2 (25(OH)D2) and parathyroid hormone (PTH) were measured at baseline and at 4, 8, 13 and 25 weeks. Geometric mean total serum 25(OH)D concentrations (sum of 25(OH)D2 and 25(OH)D3) at baseline was 80 nmol/l. After 25 weeks, participants randomised to D2 and placebo had a significant reduction in serum 25(OH)D3 concentrations over the winter months compared with vitamin D3-supplemented participants (both P< 0·001). Supplementation with vitamin D2 increased serum 25(OH)D2 but produced a 9 (95 % CI 1, 17) nmol/l greater decline in the 25(OH)D3 metabolite compared with placebo (P< 0·036). Overall, total serum 25(OH)D concentrations were 21 (95 % CI 14, 30) nmol/l lower in participants receiving vitamin D2 compared with those receiving D3 (P< 0·001), among whom total serum 25(OH)D concentrations remained unchanged. No intervention-related changes in PTH were observed. Daily supplementation of vitamin D3 was more effective than D2; however, the functional consequence of the differing metabolic response warrants further investigation.
Objective: To examine the effects of oral diazepam on blood pressure and anxiety in patients with acute epistaxis.
Study design and setting: A prospective comparative study in an otorhinolaryngology tertiary referral centre.
Participants: Patients with acute epistaxis requiring hospital admission.
Intervention: Oral diazepam.
Main outcome measures: Anxiety and blood pressure levels.
Results: 32 patients received diazepam and 45 did not (control). On average, patients were hypertensive on admission (mean [standard deviation (SD)] systolic blood pressure diazepam group=157 mmHg , control=152 mmHg ; diastolic blood pressure diazepam group=87 mmHg , control=87 mmHg ). Both groups showed significant blood pressure reduction on discharge (p<0.0001) but the difference in mean blood pressure reduction between the two groups was insignificant (systolic blood pressure p=0.16, 95% confidence interval [CI]=–5 to +19 mmHg; diastolic blood pressure p=0.43, 95% CI=–8 to +10 mmHg). Anxiety was significantly lower on discharge (p<0.0001) but the difference in mean fall in anxiety scores between the two groups was insignificant (p=0.08, 95% CI=0 to +2). There was no significant correlation between total diazepam and changes in blood pressure (systolic blood pressure p=0.32; diastolic blood pressure p=0.65) or anxiety (p=0.73), nor between blood pressure and anxiety on admission (systolic blood pressure p=0.45; diastolic blood pressure p=0.72).
Conclusions: Elevated blood pressure and anxiety in acute epistaxis patients reduced on epistaxis resolution irrespective of oral diazepam use. The elevated blood pressure does not appear to be directly related to anxiety.
The effect of different rates of potassium (K) fertilizer on the yield and quality of sugar beet was
studied in a series of 26 trials on soils of different type and K index between 1992 and 1997. There
were few yield responses even though the majority of trials were on soils of low K index, and large
quantities of fertilizer were applied (0–600 kg K/ha). Potassium offtakes (kg/ha) in the harvested beet
increased asymptotically, not linearly, with yield and were much larger for a given yield on high K
index soils than on low index soils. Commercially acceptable concentrations of beet K for processing
are in the range 700 to 1000 mg K/100 g sugar. Concentrations in excess of this decrease the amount
of sugar crystallized from the extracted juice. They were not greatly affected by large applications of
fertilizer K but were strongly influenced by long-established differences in soil exchangeable K (Kex)
due to soil type, previous cropping or manuring history.
The asymptotic nature of the K offtake[ratio ]yield relationship was confirmed by factory tarehouse
measurements relating to the national sugar beet crop delivered during the 1993–97 UK processing
campaigns. Potassium offtakes generally increased linearly with yield up to 60–70 adjusted t of clean
beet/ha, but increased little beyond that. The amount of K removed by a 60–70 t/ha crop of beet
varied from 70 kg K/ha on low K index sandy loams to 120 kg K/ha on clay soils of K index 3 and
above. Further increases in yield decreased the amount of K in fresh beet from 1·7 to 1·4 kg K/t on
low K index soils, and from 3·6 to 2·5 kg K/t on high K index soils.
An analysis of data from individual fields of commercially grown sugar beet showed that much of
the site and season variation in the K content of beet was due to differences in K uptake driven by
Kex, and to differential effects of nitrogen (N) supply on K uptake and sugar yield. Regressions on
Kex and total crop N (kg/ha) accounted for c. 30 and 50% of the variance in beet K content,
respectively, and the two together for over 60%. Total N uptake by the crops ranged from 100 to
550 kg N/ha. The total K content of the crop and the amounts of K in the beet (kg/ha) both
increased linearly with crop N over the whole of this range, whereas sugar yield increased
asymptotically with total uptakes of N up to 250–300 kg N/ha. Consequently, low yielding crops
grown on soils in which N and K were freely available produced beet of poor K quality. However,
the asymptotic relationship between beet K (kg/ha) and yield implies that, in many situations, the
processing quality of the beet could be improved by increasing yield through better agronomy.
This chapter reviews the approach and data used to determine the flux of carbon from changes in land use. Both net and gross fluxes are presented, and uncertainties in the data and in the calculated fluxes are discussed. Analyses of land-use change – based on rates of agricultural expansion, logging, and regrowth and their accompanying changes in C/ha – show that terrestrial ecosystems were a net source of approximately 120 Pg C to the atmosphere between 1850 and 1990. In 1990, the net release from changes in land use was approximately 1.7 Pg C, essentially all of it from the tropics.
These estimates of flux are higher than estimates obtained from analyses of data from forest inventories and from inverse calculations with geochemical data. Data from forest inventories show a net accumulation of approximately 0.8 Pg C/yr in northern midlatitude forests, as opposed to a flux of nearly 0 Pg C from changes in land use. Apparently these northern forests are either recovering from harvests more rapidly than they did in the past or accumulating carbon in areas not directly affected by human management. If the analyses of forest inventories are correct, the imbalance in the global carbon equation is approximately half (0.7–0.8 Pg C/yr) what it was when defined on the basis of land-use change. The smaller estimate of missing carbon is unlikely to be found in the trees of midlatitude forests. The additional sink would require a systematic error of about 100% in the observed rates of growth.
It is demonstrated that the time required for strain transference during the postgrowth anneal of a SOI compliant substrate system is much too long to explain the observed reduction in dislocation density in the resulting microstructure. A mechanism by which misfit dislocation segments are drawn out of the system through viscous dissipation in the bonding layer is proposed and demonstrated to be consistent with observation. The mechanism is mtodeled in the context of elastic dislocation theory and linear viscoelasticity.