First observation of 28O.

Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10-21 s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28O and 27O through their decay into 24O and four and three neutrons, respectively. The 28O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers1,2, it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called 'doubly magic' nuclei. Both 27O and 28O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28O from a 29F beam is consistent with it not exhibiting a closed N = 20 shell structure.

Experimental hyperoxia (O2 supersaturation) reveals a gill diffusion limitation of maximum aerobic performance in fish.

Several studies have demonstrated that hyperoxia increases the maximal O2 consumption rate (MO2max) in fish, but exactly how this occurs remains to be explained. Here, we tested the hypothesis that hyperoxia improves arterial oxygenation in rainbow trout during exhaustive exercise. We demonstrate a 35% higher MO2max in hyperoxia (200% air saturation) relative to normoxia, which was achieved through a combined 15% increase in cardiac output due to elevated peak heart rate, and a 19% increase of the arterial-venous (A-V) O2 content difference. While arterial O2 partial pressure (PaO2) and O2 saturation of haemoglobin declined post-exhaustive exercise in normoxia, this did not occur in hyperoxia. This protective effect of hyperoxia on arterial oxygenation led to a 22% higher arterial O2 content post-exhaustive exercise, thereby allowing a higher A-V O2 content difference. These findings indicate that MO2max is gill diffusion limited in exhaustively exercised rainbow trout. Moreover, as previous studies in salmonids have demonstrated collapsing PaO2 in normoxia at maximal swimming speed and at acutely high temperatures, a diffusion limitation may constrain MO2 in other situations eliciting peak metabolic demand. These findings, along with the fact that hyperoxia increases MO2max in several other fishes, suggest that gill diffusion limitations of MO2max may be widespread in fishes.

Prevalence and mechanisms of environmental hyperoxia-induced thermal tolerance in fishes.

Recent evidence has suggested environmental hyperoxia (O2 supersaturation) can boost cardiorespiratory performance in aquatic ectotherms, thereby increasing resilience to extreme heat waves associated with climate change. Here, using rainbow trout (Oncorhynchus mykiss) as a model species, we analysed whether improved cardiorespiratory performance can explain the increased thermal tolerance of fish in hyperoxia (200% air saturation). Moreover, we collated available literature data to assess the prevalence and magnitude of hyperoxia-induced thermal tolerance across fish species. During acute warming, O2 consumption rate was substantially elevated under hyperoxia relative to normoxia beyond 23°C. This was partly driven by higher cardiac output resulting from improved cardiac contractility. Notably, hyperoxia mitigated the rise in plasma lactate at temperatures approaching upper limits and elevated the critical thermal maximum (+0.87°C). Together, these findings show, at least in rainbow trout, that hyperoxia-induced thermal tolerance results from expanded tissue O2 supply capacity driven by enhanced cardiac performance. We show 50% of the fishes so far examined have increased critical thermal limits in hyperoxia (range: 0.4-1.8°C). This finding indicates environmental hyperoxia could improve the ability of a large number of fishes to cope with extreme acute warming, thereby increasing resilience to extreme heat wave events resulting from climate change.

Field assessments of heart rate dynamics during spawning migration of wild and hatchery-reared Chinook salmon.

During spawning, adult Pacific salmonids (Oncorhynchus spp.) complete challenging upriver migrations during which energy and oxygen delivery must be partitioned into activities such as locomotion, maturation and spawning behaviours under the constraints of an individual's cardiac capacity. To advance our understanding of cardiac function in free-swimming fishes, we implanted migrating adult Chinook salmon (Oncorhynchus tshawytscha) collected near the mouth of the Sydenham River, Ontario, with heart rate (fH) biologgers that recorded fH every 3 min until these semelparous fish expired on spawning grounds several days later. Fundamental aspects of cardiac function were quantified, including resting, routine and maximum fH, as well as scope for fH (maximum-resting fH). Predictors of fH were explored using generalized least-squares regression, including water temperature, discharge, fish size and fish origin (wild versus hatchery). Heart rate was positively correlated with water temperature, which aligned closely with daily and seasonal shifts. Wild fish had slower resting heart rates than hatchery fish, which led to significantly higher scope for fH. Our findings suggest that wild salmon may have better cardiac capacity during migration than hatchery fish, potentially promoting migration success in wild fish. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.

First-Time Fathers' Experience of Support from Midwives in Maternity Clinics: An Interview Study.

BACKGROUND: Research shows that first-time fathers want to take part in preparation for birth and parenthood but they describe being excluded by health professionals. AIM: The aim of this study was to illustrate first-time fathers' experiences of support from midwives in maternity clinics as a step in the validation of "The Father Perceived-Professional-Support" (The FaPPS) scale. METHODS: A qualitative content analysis with an inductive and deductive approach was used; seven first-time fathers were strategically selected and interviewed. In the inductive part the following open question was asked: "How did you perceive the support from the antenatal midwife/midwives?" In the deductive part, the fathers were asked to respond to the FaPPS scale, in order to receive their thoughts and understanding of the scale, inspired by the "Think-aloud" method. FINDINGS: The inductive results showed two main categories: Experience of not knowing what support they needed and Experience of being excluded. The fathers found support from other fathers in parental education classes, but they lack time to discuss. Overall it seems as if the fathers answered both from their own perspective and from the mothers' perspective. This was not evident in the deductive results. The FaPPs scale should therefore include professionals' ability to strengthen social support from other first-time fathers and professionals' ability to offer support to the mother. Conclusion and Clinical Implications. The fathers experienced exclusion both by themselves and also by midwives. Midwives should offer both parents the opportunity to pose questions. It is important for expectant fathers that time for discussion is planned in parental education classes. The FaPPS scale is useful but needs further development. Parts of our result are in line with earlier research, for decades; therefore it is necessary to focus more on support for fathers.

Erratum: Spectroscopic Quadrupole Moments in

This corrects the article DOI: 10.1103/PhysRevLett.116.022701.

Spectroscopic Quadrupole Moments in {96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.

Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.

Warming alters the body shape of European perch Perca fluviatilis.

The consequences of elevated temperature on body shape were investigated by comparing European perch Perca fluviatilis from the Forsmark area of the Baltic Sea to P. fluviatilis from a nearby Biotest enclosure. The Biotest is a man-made enclosure within the Baltic Sea that has received warm water from a nuclear power plant since 1980, resulting in temperatures that are elevated 5-10 °C relative to the surrounding Baltic Sea. Sampled fish ranged from young-of-the-year to 14 years. Geometric morphometrics and multivariate statistical analysis revealed significant morphological differences between individuals of P. fluviatilis from these two habitats. Most importantly, relative shape changed with size, with small individuals of P. fluviatilis from Biotest being characterized by a deeper body shape and a larger caudal peduncle than the smaller Baltic individuals. In large specimens, smaller differences were found with Biotest individuals being more slender than Baltic individuals. These results show that, in order to have a full understanding of the biological effects of elevated temperatures, studies that cover the entire size range of organisms will be important. Apart from the direct influence of temperature on growth rate and body shape, other ecological factors affected by temperature are discussed as possible contributors to the observed differences between the two populations.

Assessing the tongue colour of newly born infants may help to predict the need for supplemental oxygen in the delivery room.

AIM: It takes several minutes for infants to become pink after birth. Preductal oxygen saturation (SpO2) measurements are used to guide the delivery of supplemental oxygen to newly born infants, but pulse oximetry is not available in many parts of the world. We explored whether the pinkness of an infant's tongue provided a useful indication that supplemental oxygen was required. METHODS: This was a prospective observational study of infants delivered by Caesarean section. Simultaneous recording of SpO2 and visual assessment of whether the tongue was pink or not was made at 1-7 and 10 min after birth. RESULTS: The 38 midwives and seven paediatric trainees carried out 271 paired assessments on 68 infants with a mean (SD) birthweight of 3214 (545) grams and gestational age of 38 (2) weeks. When the infant did not have a pink tongue, this predicted SpO2 of <70% with a sensitivity of 26% and a specificity of 96%. CONCLUSION: Tongue colour was a specific but insensitive sign that indicated when SpO2 was <70%. When the tongue is pink, it is likely that an infant has an SpO2 of more than 70% and does not require supplemental oxygen.

Shape coexistence in the neutron-deficient even-even (182-188)Hg isotopes studied via coulomb excitation.

Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85 MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0+ states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0+ state was noted in Hg182,184. The results are compared to beyond mean field and interacting-boson based models and interpreted within a two-state mixing model. Partial agreement with the model calculations was obtained. The presence of two different structures in the light even-mass mercury isotopes that coexist at low excitation energy is firmly established.

Effects of three-nucleon forces and two-body currents on Gamow-Teller strengths.

We optimize chiral interactions at next-to-next-to leading order to observables in two- and three-nucleon systems and compute Gamow-Teller transitions in 14C and (22,24)O using consistent two-body currents. We compute spectra of the daughter nuclei 14N and (22,24)F via an isospin-breaking coupled-cluster technique, with several predictions. The two-body currents reduce the Ikeda sum rule, corresponding to a quenching factor q2≈0.84-0.92 of the axial-vector coupling. The half-life of 14C depends on the energy of the first excited 1+ state, the three-nucleon force, and the two-body current.

Optimized chiral nucleon-nucleon interaction at next-to-next-to-leading order.

We optimize the nucleon-nucleon interaction from chiral effective field theory at next-to-next-to-leading order (NNLO). The resulting new chiral force NNLO(opt) yields χ(2)≈1 per degree of freedom for laboratory energies below approximately 125 MeV. In the A=3, 4 nucleon systems, the contributions of three-nucleon forces are smaller than for previous parametrizations of chiral interactions. We use NNLO(opt) to study properties of key nuclei and neutron matter, and we demonstrate that many aspects of nuclear structure can be understood in terms of this nucleon-nucleon interaction, without explicitly invoking three-nucleon forces.

Dietary quercetin intake and risk of gastric cancer: results from a population-based study in Sweden.

BACKGROUND: To study the impact of the dietary antioxidant quercetin on risk of gastric adenocarcinoma. PATIENTS AND METHODS: Using data from a large Swedish population-based case-control study of gastric cancer (505 cases and 1116 controls), we studied the association between quercetin and risk of anatomic (cardia/noncardia) and histological (intestinal and diffuse) subtypes of gastric cancer. RESULTS: We found strong inverse associations between quercetin and the risk of noncardia gastric adenocarcinoma, with an adjusted odds ratio (OR) of 0.57 (95% confidence interval 0.40-0.83) for the highest quintile (≥11.9 mg) of daily quercetin intake relative to the lowest quintile of intake (<4 mg quercetin/day), supported by a significant decreasing linear trend (P value < 0.001). Similar findings were observed for the intestinal and diffuse subtype. For cardia cancer, we found a less evident and nonsignificant inverse relationship. The protection of quercetin appeared to be stronger among female smokers, with the OR leveled of at values <0.2 in quintiles 3-5 (>6 mg quercetin/day). CONCLUSIONS: High dietary quercetin intake is inversely related to the risk of noncardia gastric adenocarcinoma, and the protection appears to be particularly strong for women exposed to oxidative stress, such as tobacco smoking.

`Keeping Healthy in the Backseat': How Motherhood Interrupted HIV Treatment in Recently Delivered Women in Kenya

Although there is a large body of literature related to the experiences of motherhood and aspects of the change that it brings about; how the experience of motherhood affects the healthcare of women with chronic illness is less documented. This study explores how motherhood in newly delivered HIV-infected mothers in Kenya interrupted their antiretroviral treatment (ART). Qualitative interviews were performed with 26 mothers on ART in a rural or urban area. The data were organised and interpreted using content analysis. The study found that adherence to ART was influenced by contextual differences in socio-cultural expectations and family relationships. Urban life enabled women to make decisions on their own and to negotiate challenges that were often unpredictable. Women in rural areas knew what was expected of them and decisions were normally not for them to make alone. The women in Busia and Kibera had difficulties combining adherence with attaining the socio-cultural definition of good mothering. Lack of support from health providers and weak healthcare systems contributed to inadequate stocks of HIV drugs and inaccessibility of HIV-related care. From the data; we developed the main theme `keeping healthy in the backseat' and the two sub-themes `regaining self-worth through motherhood' and `mother first - patient later.' We suggest that motherhood is context-specific and follows socio-cultural practises; which made it difficult for the women in Kenya to follow ART instructions. There is a need to reassess HIV-related services for mothers on ART in order to give them a better chance to stay on treatment and satisfy their aspiration to be `good mothers.' Contextspecific HIV-treatment policies are necessary for ensuring adherence and successful treatment outcomes

The Dilemma of Safe Sex and Having Children: Challenges Facing HIV Sero-Discordant Couples in Uganda

Background: Sixty percent of new HIV infections in Uganda occur in stable relationships between HIV discordant couples. Given the importance of fertility in Uganda; we hypothesized that unsafe sexual practices may be used to found a family/replace a dead child. Thus; we explored sexual practices to understand to what extent these are influenced by the desire to have children and the implications for HIV transmission among discordant couples. Methods: A cross-sectional survey of 114 HIV discordant couples in Kampala; and in-depth interviews with 15 purposively selected couples. Quantitative data were analysed using STATA. Multivariate logistic regression analysis done to identify factors associated with consistent condom use. Thematic content analysis of qualitative data was done using NVIVO 2. Results: Participants wanting children and those with multiple sexual partners were less likely to use condoms (Adj OR 0.51; and 0.36 respectively). Three of the five types of sexual practices used by couples do not allow pregnancy to occur. Main reasons for wanting a child included: ensuring lineage continuity and posterity; securing relationships and pressure from relatives to reproduce. Challenges included: risk of HIV transmission to partner and child; lack of negotiating power for safer sex; failure of health systems to offer safe methods of reproduction. Conclusions: HIV sero-discordant couples with strong desire for childbearing have a dilemma of risking HIV infection or infecting their spouse. Some risk transmission of HIV infection to reproduce. We need to address gender issues; risky behaviour and reproductive health services for HIV sero-discordant couples

0(gs)+ -->2(1)+ transition strengths in 106Sn and 108Sn.

The reduced transition probabilities, B(E2; 0(gs)+ -->2(1)+), have been measured in the radioactive isotopes (108,106)Sn using subbarrier Coulomb excitation at the REX-ISOLDE facility at CERN. Deexcitation gamma rays were detected by the highly segmented MINIBALL Ge-detector array. The results, B(E2;0(gs)+ -->2(1)+)=0.222(19)e2b2 for 108Sn and B(E2; 0(gs)+-->2(1)+)=0.195(39)e2b2 for 106Sn were determined relative to a stable 58Ni target. The resulting B(E2) values are approximately 30% larger than shell-model predictions and deviate from the generalized seniority model. This experimental result may point towards a weakening of the N=Z=50 shell closure.

Interplay between single-particle and collective effects in the odd-A Cu isotopes beyond N=40.

Collective properties of the low-lying levels in the odd-A 67-73Cu were investigated by Coulomb excitation with radioactive beams. The beams were produced at ISOLDE and postaccelerated by REX-ISOLDE up to 2.99 MeV/u. In 67,69Cu, low-lying 1/2(-), 5/2(-), and 7/2(-) states were populated. In 71,73Cu, besides the known transitions deexciting the single-particle-like 5/2(-) and core-coupled 7/2(-) levels, gamma rays of 454 and 135 keV, respectively, were observed for the first time. Based on a reanalysis of beta-decay work and comparison with the systematics, a spin 1/2(-) is suggested for these excited states. Three B(E2) values were determined in each of the four isotopes. The results indicate a significant change in the structure of the odd-A Cu isotopes beyond N=40 where single-particle-like and collective levels are suggested to coexist at very low excitation energies.

Reduced cortical thickness in hippocampal subregions among cognitively normal apolipoprotein E e4 carriers.

Our objective was to investigate whether asymptomatic carriers of apolipoprotein E epsilon4 [APOE-4] demonstrate pathological differences and atrophy in medial temporal lobe (MTL) subregions. We measured cortical thickness and volume in MTL subregions (hippocampal CA fields 1, 2 and 3; dentate gyrus; entorhinal cortex; subiculum; perirhinal cortex; parahippocampal cortex; and fusiform gyrus) using a high-resolution in-plane (0.4x0.4 mm) MRI sequence in 30 cognitively normal volunteers (14 APOE-4 carriers, 16 non-carriers, mean age 57 years). A cortical unfolding procedure maximized the visibility of this convoluted cortex, providing cortical ribbon thickness measures throughout individual subregions of the hippocampus and surrounding cortex. APOE-4 carriers had reduced cortical thickness compared with non-carriers in entorhinal cortex (ERC) and the subiculum (Sub), but not in the main hippocampal body or perirhinal cortex. Average cortical thickness was 14.8% lower (p=1.0e(- 6)) for ERC and 12.6% lower (p=6.8e(- 5)) for Sub in APOE-4 carriers. Standard volumetric measures of the same regions showed similar, but non-significant trends. Cognitively intact carriers of APOE-4 show regionally specific thinning of the cortical ribbon compared to APOE-3 carriers; cortical thickness may be a more sensitive measure of pathological differences in genetic risk subjects than standard volumetry.

Reasons for unsatisfactory acceptance of antiretroviral treatment in the urban Kibera slum, Kenya.

The aim of this study was to explore why patients in the urban Kibera slum, Nairobi, Kenya, offered free antiretroviral treatment (ART) at the Médecins Sans Frontièrs (MSF) clinic, choose not to be treated despite signs of AIDS. Qualitative semi-structured interviews were conducted with 26 patients, 9 men and 17 women. Six main reasons emerged for not accepting ART: a) fear of taking medication on an empty stomach due to lack of food; b) fear that side-effects associated with ART would make one more ill; c) fear of disclosure and its possible negative repercussions; d) concern for continuity of treatment and care; e) conflicting information from religious leaders and community, and seeking alternative care (e.g. traditional medicine); f) illiteracy making patients unable to understand the information given by health workers.