Enhanced mixing across the gyre boundary at the Gulf Stream front.

The Gulf Stream front separates the North Atlantic subtropical and subpolar ocean gyres, water masses with distinct physical and biogeochemical properties. Exchange across the front is believed to be necessary to balance the freshwater budget of the subtropical gyre and to support the biological productivity of the region; however, the physical mechanisms responsible have been the subject of long-standing debate. Here, the evolution of a passive dye released within the north wall of the Gulf Stream provides direct observational evidence of enhanced mixing across the Gulf Stream front. Numerical simulations indicate that the observed rapid cross-frontal mixing occurs via shear dispersion, generated by frontal instabilities and episodic vertical mixing. This provides unique direct evidence for the role of submesoscale fronts in generating lateral mixing, a mechanism which has been hypothesized to be of general importance for setting the horizontal structure of the ocean mixed layer. Along the Gulf Stream front in the North Atlantic, these observations further suggest that shear dispersion at sharp fronts may provide a source of freshwater flux large enough to explain much of the freshwater deficit in the subtropical-mode water budget and a flux of nutrients comparable to other mechanisms believed to control primary productivity in the subtropical gyre.

Advances in the Direct Study of Carbon Burning in Massive Stars.

The ^{12}C+^{12}C fusion reaction plays a critical role in the evolution of massive stars and also strongly impacts various explosive astrophysical scenarios. The presence of resonances in this reaction at energies around and below the Coulomb barrier makes it impossible to carry out a simple extrapolation down to the Gamow window-the energy regime relevant to carbon burning in massive stars. The ^{12}C+^{12}C system forms a unique laboratory for challenging the contemporary picture of deep sub-barrier fusion (possible sub-barrier hindrance) and its interplay with nuclear structure (sub-barrier resonances). Here, we show that direct measurements of the ^{12}C+^{12}C fusion cross section may be made into the Gamow window using an advanced particle-gamma coincidence technique. The sensitivity of this technique effectively removes ambiguities in existing measurements made with gamma ray or charged-particle detection alone. The present cross-section data span over 8 orders of magnitude and support the fusion-hindrance model at deep sub-barrier energies.

Anomalies in the Charge Yields of Fission Fragments from the

Fast-neutron-induced fission of ^{238}U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ-γ coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fast-neutron-induced fission than for thermal neutron-induced fission. This has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.

Rapid vertical exchange at fronts in the Northern Gulf of Mexico.

Over the Texas-Louisiana Shelf in the Northern Gulf of Mexico, the eutrophic, fresh Mississippi/Atchafalaya river plume isolates saltier waters below, supporting the formation of bottom hypoxia in summer. The plume also generates strong density fronts, features of the circulation that are known pathways for the exchange of water between the ocean surface and the deep. Using high-resolution ocean observations and numerical simulations, we demonstrate how the summer land-sea breeze generates rapid vertical exchange at the plume fronts. We show that the interaction between the land-sea breeze and the fronts leads to convergence/divergence in the surface mixed layer, which further facilitates a slantwise circulation that subducts surface water along isopycnals into the interior and upwells bottom waters to the surface. This process causes significant vertical displacements of water parcels and creates a ventilation pathway for the bottom water in the northern Gulf. The ventilation of bottom water can bypass the stratification barrier associated with the Mississippi/Atchafalaya river plume and might impact the dynamics of the region's dead zone.

Development of a reference material for analysing naturally occurring radioactive material from the steel industry.

Accurate measurement of naturally occurring radionuclides in blast furnace slag, a by-product of the steel industry, is required for compliance with building regulations where it is often used as an ingredient in cement. A matrix reference blast furnace slag material has been developed to support traceability in these measurements. Raw material provided by a commercial producer underwent stability and homogeneity testing, as well as characterisation of matrix constituents, to provide a final candidate reference material. The radionuclide content was then determined during a comparison exercise that included 23 laboratories from 14 countries. Participants determined the activity per unit mass for 226Ra, 232Th and 40K using a range of techniques. The consensus values obtained from the power-moderated mean of the reported participant results were used as indicative activity per unit mass values for the three radionuclides: A0(226Ra) = 106.3 (34) Bq·kg-1, A0(232Th) = 130.0 (48) Bq·kg-1 and A0(40K) = 161 (11) Bq·kg-1 (where the number in parentheses is the numerical value of the combined standard uncertainty referred to the corresponding last digits of the quoted result). This exercise helps to address the current shortage of NORM industry reference materials, putting in place infrastructure for production of further reference materials.

The impact of high-energy tailing in high-purity germanium gamma-ray spectrometry on the activity determination of 224Ra using the 241.0 keV emission.

High-energy tailing is an often-overlooked component in high-purity germanium gamma-ray spectrometry when performing the non-linear least squares fit of a full-energy peak. This component comes from the incomplete restoration of the baseline prior to the next pulse being processed and therefore is an issue of increased count rates. In the current work, the impact of this oversight is shown through the dynamics and decay characteristics of 224Ra and its radioactive decay progeny. Multiple measurements of two samples, separated from the decay progeny and at differing activities, have been made. The results of full-energy peak fitting of the convoluted 238.6 keV and 241.0 keV full-energy peaks with and without the high energy tailing component are presented. Trends in the observed activity that approximate the ingrowth of 212Pb have been observed where no high-energy tailing component is used, with maximum relative differences of 2% and 5% determined.

Evolutionary exploitation of design options by the first animals with hard skeletons.

The set of viable design elements available for animals to use in building skeletons has been fully exploited. Analysis of animal skeletons in relation to the multivariate, theoretical "Skeleton Space" has shown that a large proportion of these options are used in each phylum. Here, we show that structural elements deployed in the skeletons of Burgess Shale animals (Middle Cambrian) incorporate 146 of 182 character pairs defined in this morphospace. Within 15 million years of the appearance of crown groups of phyla with substantial hard parts, at least 80 percent of skeletal design elements recognized among living and extinct marine metazoans were exploited.

Investigation of γ-γ coincidence counting using the National Nuclear Array (NANA) as a primary standard.

The National Physical Laboratory has recently been in the process of commissioning a multi-detector γ ray array - the National Nuclear Array (NANA). In this study we have sought to exploit the NANA and the excellent timing characteristics of its intrinsic LaBr3(Ce) scintillation detectors for use as a primary standardisation system. For this initial investigation, the absolute standardisation of 60Co has been performed by the γ-γ coincidence technique using NANA and the result compared to the established 4π(LS)-γ Digital Coincidence Counting (DCC) system. The effect of the angular correlation of the stretched E2 transitions emitted from the 4+→2+→0 states of 60Ni on the activity determined by NANA was observed between the pairs of detectors. Corrections for these angular correlations were derived through Monte Carlo simulations. An activity per unit mass by NANA of 330.8 (10) kBqg-1 for the 60Co solution was determined. There was no significant statistical difference between the results of NANA and the 4π(LS)-γ DCC, with a relative difference of 0.04% observed. This study shows that NANA can be used as a primary standard.

Development of the NPL gamma-ray spectrometer NANA for traceable nuclear decay and structure studies.

We present a brief report on the progress towards the construction of the National Nuclear Array (NANA), a gamma-ray coincidence spectrometer for discrete-line nuclear structure and decay measurements. The proposed spectrometer will combine a gamma-ray energy resolution of approximately 3% at 1MeV with sub-nanosecond timing discrimination between successive gamma rays in mutually coincident decay cascades. We also review a number of recent measurements using coincidence fast-timing gamma-ray spectroscopy for nuclear structure studies, which have helped to inform the design criteria for the NANA spectrometer.

Anomalous Near-Surface Low-Salinity Pulses off the Central Oregon Coast.

From mid-May to August 2011, extreme runoff in the Columbia River ranged from 14,000 to over 17,000 m(3)/s, more than two standard deviations above the mean for this period. The extreme runoff was the direct result of both melting of anomalously high snowpack and rainfall associated with the 2010-2011 La Niña. The effects of this increased freshwater discharge were observed off Newport, Oregon, 180 km south of the Columbia River mouth. Salinity values as low as 22, nine standard deviations below the climatological value for this period, were registered at the mid-shelf. Using a network of ocean observing sensors and platforms, it was possible to capture the onshore advection of the Columbia River plume from the mid-shelf, 20 km offshore, to the coast and eventually into Yaquina Bay (Newport) during a sustained wind reversal event. Increased freshwater delivery can influence coastal ocean ecosystems and delivery of offshore, river-influenced water may influence estuarine biogeochemistry.

Characteristics of an antiluteinizing hormone isoantibody produced during gonadotropin induction of ovulation.

Production of an antihuman LH antibody was suspected in a woman with isolated LH deficiency who received human pituitary gonadotropin (hPG) to induce ovulation and who developed secondary drug failure associated with very high "serum LH' values. Binding of [125I]LH to various dilutions of the patient's serum was demonstrated by precipitation with polyethylene glycol or sheep antihuman immunoglobulin G (anti-IgG) but not by precipitation with sheep antihuman immunoglobulin M (anti-IgM). Unlabeled LH competitively displaced [125I]LH from a 1:200 final dilution of the patient's serum, and indicated a single class of binding sites with a binding affinity of 1.5 X 1011 M-1 and a binding capacity of 84 ng LH/ml serum. The isoantibody was reactive against antigenic determinants in hPG, LH, and hCG but not against human FSH. Further examination showed binding to the beta, but not the alpha, subunit of two LH preparations and to beta hCG. It is concluded that repeated administration of hPG to this patient with isolated LH deficiency evoked IgG isoantibody formation against the beta subunit of LH.

Familial hyperinsulinemia complicated by extreme insulin resistance during pregnancy: a probable postreceptor defect.

Detailed studies of a family with hyperinsulinemia are reported. The index patient, a 30-yr-old woman with polycystic ovary syndrome, presented with gestational diabetes which was completely resistant to insulin in the presence of severe endogenous hyperinsulinemia. Sensitivity to insulin was regained after delivery. Therapy with cyproterone acetate and ethinyl estradiol for hirsutism exacerbated the hyperinsulinemia toward the levels occurring in pregnancy, with a concomitant deterioration of glucose tolerance. Five other members of her family also were found to have hyperinsulinemia together with high concentrations of circulating C-peptide. Antibodies to insulin and to insulin receptors were not detected, insulin antagonists were not increased, and insulin degradation in the circulation was normal. Insulin extracted from the patient's serum was identical to normal insulin by the criteria of Sephadex chromatography, placental membrane insulin receptor binding, and stimulation of 2-deoxyglucose uptake in isolated rat adipocytes. Although [125I]insulin binding to erythrocytes of all family members and to the patient's placental membranes was markedly reduced, binding to fibroblast cultures from the patient was normal. Insulin-stimulated glucose transport in these fibroblasts also was normal, but there was a mild (20%) reduction in the concentration of cytochalasin B-binding sites in erythrocyte ghosts. Insulin resistance in this family may be due to a partial defect distal to the insulin receptor. This is asymptomatic unless metabolic stresses (pregnancy or steroid administration) are superimposed.

Oestrone, oestradiol-17beta and oestriol levels in human foetal plasma during gestation and at term.

PIP: Marked rises in both unconjugated and sulphoconjugated estrone, estradiol-17-beta and estriol were observed in human fetal plasma between midgestation and term. Significant arterio-venous differences were found in the umbilical cord plasma. No consistent arterio-venous differences were found in the umbilical cord plasma. This indicates that all 3 estrogens are secreted from the placenta into the fetal circulation in the unconjugated form. Mean unconjugated estrogen (estrone + estradiol-17-beta + estriol) levels rose from 22.7 ng/ml at 17-20 weeks of gestation to 108.9 ng/ml at term in umbilical venous plasma and from 4.3 ng/ml to 23.3 ng/ml in umbilical arterial plasma. This represents a secretion rate of approximately 30 mg estrogen/day into the umbilical vein at term. Mean estrogen sulphate levels rose from 128 ng/ml to 313 ng/ml in the cord plasma during the same period. Of the 3 estrogens measured, estriol was quantitatively the major estrogen in fetal plasma. It consistently represented about 78% of the unconjugated fraction and 95% of the sulphate fraction at all stages of gestation. The method of delivery did not have a significant effect on the estrogen levels in uncomplicated pregnancies. Similar estrogen levels were found in fetal heart blood after either hysterotomy at spontaneous abortion at 16-20 weeks of gestation, and no significant differences were found for estrogen levels in cord plasma after elective Caesarean section at 38-39 weeks when compared with estrogen levels after normal delivery at term. A significant rise in fetal unconjugated estrogens at a time when fetal corticosteroids are increasing may be of physiological importance for fetal maturation in women.^ieng

Studies of human chorionic gonadotrophin, placental lactogen, and progesterone secretion in vitro.

The relative ability of explants of villous tissue from 8- to 10-week placenta to synthesize and release human chorionic gonadotrophin (HCG), human placental lactogen (HPL) and progesterone in culture was investigated. It was found that the synthesis and release of all three hormones was two to four times greater than the initial tissue content in the first 24 hours in culture. Between 24 and 48 hours of the secretion of HCG, HPL and progesterone was reduced to about 40 per cent, 20 per cent and 60 per cent respectively of that produced in the previous 24 hours. These results support previous findings that the production of HPL is more labile than HCG in culture, and suggest that progesterone secretion under the present conditions is least affected. When azastene (4, 4, 17 alpha-trimethylandrost-5-eno (2,3-d) isoxazol-17-ol), an inhibitor of gonadal and placental 3 beta-hydroxy steroid dehydrogenase conversion of pregnenolone to progesterone in rhesus monkeys, was added to the culture medium at a concentration of 0.3-150 mumol/l, no marked effect on the secretion of progesterone was observed. This indicates that the dehydrogenase in human placental tissue is either less accessible to azastene or that the inhibitory activity in the rhesus monkey was due to a metabolite of azastene.

Plasma prolactin levels and ovarian responsiveness to exogenous gonadotropins.

Standard gonadotropin stimulation tests of ovarian function and basal plasma prolactin measurements have been carried out in 151 patients with amenorrhea or severe oligomenorrhea. In 90 of these a standardized multiple pituitary stimulation test, including the prolactin response to thyrotropin releasing hormone, was also performed. There was a tendency for the basal estrogen excretion and the ovarian response to gonadotropin to be lower in patients with hyperprolactinemia. These correlations were weak and did not reach the levels of statistical significance except when compareing the ovariance response in patients with mild hyperprolactinemia to those with moderate or severe hyperprolactinemia. It is concluded that, in women, elevated plasma prolactin levels have little, if any, direct inhibitory influence on the ovariance response to gonadotropins in vivo.

Antecedent factors and outcome in amenorrhea-galactorrhea.

One hundred seventeen patients with amenorrhea and galactorrhea or hyperprolactinemia were evaluated with regard to antecedent factors, results of investigations, and management. Full details of the outcome of prolonged follow-up were available for 104 patients. Patients who developed amenorrhea-galactorrhea after withdrawal of oral contraceptives or postpartum had a lower incidence of pituitary adenomas than did those who developed amenorrhea-galactorrhea spontaneously. Six of a total of 40 tumors were detected only during the follow-up period. This study suggests that patients with spontaneous amenorrhea-galactorrhea have a greater risk of developing a detectable pituitary adenoma than do those with postpill or postpartum symptoms. However, patients with a microadenoma are more likely to have had postpill onset of hyperprolactinemia. Plasma prolactin (PRL) in patients with postpill amenorrhea-galactorrhea increased in proportion to the duration of oral contraceptive use.

Efficacy of mefenamic acid in patients with a complaint of menorrhagia.

Sixty-nine patients with a convincing history of menorrhagia completed a 4-cycle double-blind randomized placebo-controlled crossover trial of mefenamic acid taken during menstruation. Only 30 of these patients demonstrated objective menorrhagia with a measured menstrual loss greater than 80 ml during the placebo cycles, but the remainder reported passing clots and/or using 2 pads at a time. Fourteen of these women (20%) had a loss of less than 35 ml while taking placebos. This raises serious questions about the establishment of menorrhagia based on history alone. Overall, there was a mean reduction of 28.1% in menstrual blood loss between placebo and mefenamic acid cycles (P less than .001). The greatest reduction recorded was 80%, and most of the large percentage reductions were seen in patients with high loss during placebo cycles. Significant reductions in blood loss (P less than .001) were seen in patients with ovulatory dysfunctional uterine bleeding and menorrhagia that developed after tubal interruption. There was also an indication based on small sample sizes that mefenamic acid reduced blood loss in women with anovulatory dysfunctional uterine bleeding, fibroids, intrauterine devices, and von Willebrand disease. No reduction was seen during the mefenamic acid cycle in the group with a loss of less than 35 ml during the placebo cycle. There was a significant shortening of duration of bleeding (P less than .003). Fifteen patients (21.7%) experienced no objective reduction in blood loss.

Pregnancy in women with Kallmann's syndrome.

OBJECTIVE: To induce of ovulation and pregnancy in women with Kallmann's syndrome. DESIGN: Retrospective study. PATIENTS: Three women with hypogonadotropic hypogonadism and anosmia with a desire for pregnancy. INTERVENTIONS: Investigation of hypothalamic-pituitary-ovarian function and induction of ovulation by pulsatile GnRH or intramuscular human pituitary gonadotropins (hPG) or hMG with hCG. MAIN OUTCOME MEASURES: Successful induction of ovulation as measured by serum P levels and successful pregnancy. RESULTS: Ovulation was induced successfully in all three patients on more than one occasion and nine pregnancies occurred. Gonadotropin-releasing hormone was given IV by an electronically timed syringe driver. A total of 12 pulsatile GnRH cycles resulted in two pregnancies, 6 of these cycles being in one patient who did not ovulate or conceive with this therapy. Ovulation occurred in 10 of 16 hMG or hPG cycles, with conception in 7 of these. Gonadotropin usage was higher in these women compared with women with hypogonadotropic hypogonadism without anosmia (2,850 compared with 2,100 IU per treatment cycle), and the follicular phase was longer. CONCLUSIONS: All three women conceived and had children after induction of ovulation. The success rate of these therapies in Kallmann's syndrome appears to be high in spite of very few reports in the literature.

An association among blepharophimosis, resistant ovary syndrome, and true premature menopause.

Four cases are described of a very rare association among blepharophimosis, resistant ovary syndrome, and true premature menopause. Plasma levels of follicle-stimulating hormone and luteinizing hormone were significantly elevated and estradiol significantly decreased in all four cases. Ovarian biopsies demonstrated large numbers of unstimulated primordial follicles in three cases and no follicles in one case. Two of the four women were sisters, with the older having true premature menopause and the younger having resistant ovary syndrome. The explanation for the association of blepharophimosis with primary ovarian dysfunction is unknown, but the possibility of a microdeletion of genetic material containing two geographically associated but independent genes could not be confirmed or excluded by high-resolution chromosome banding. All families affected by the autosomal dominant condition of blepharophimosis should be counseled about the high incidence of ovarian dysfunction and female infertility, at least in one form of the syndrome.

Pulsatile intravenous gonadotropin-releasing hormone for ovulation-induction in infertile women. II. Analysis of follicular and luteal phase responses.

Pulsatile intravenous gonadotropin releasing hormone (IV-GnRH) was used in 36 infertile patients with primary amenorrhea (n = 5), secondary amenorrhea due to hypothalamic chronic anovulation (HCA) (n = 22), hyperprolactinemia (n = 1) or polycystic ovary syndrome (PCOS) (n = 5), and oligomenorrhea (n = 3), using several dosage and timing regimens. Early follicular phase responses showed four patterns: type 1 consisted of a delayed follicle-stimulating hormone (FSH) peak and was seen with severe hypothalamic suppression (n = 4); type 2 consisted of a brisk and dominant FSH peak on the first day of treatment, and occurred with mild to moderate hypothalamic suppression (n = 19); type 3, which consisted of an FSH peak accompanied by an immediate and exaggerated luteinizing hormone (LH) rise, occurred with mild PCOS and some cases of HCA (n = 5); and type 4, in which LH levels were high to begin with and neither FSH nor LH levels rose with GnRH, occurred with severe PCOS (n = 2). Exaggerated estradiol responses within 24 hours of therapy were seen in eight cycles: in four cases no ovarian abnormality was apparent; in three cases a dominant follicle was already present; and in one case ovarian hyperstimulation was diagnosed ultrasonographically. With standard human chorionic gonadotropin luteal phase support, luteal phase defects were rare with HCA but common with PCOS.