Igneous Rock Associations 11. The Geology and Petrology of Seafloor Volcanic Rocks of the Northeastern Pacific Ocean, Offshore Canada

The seafloor within Canada’s Exclusive Economic Zone in the northeastern Pacific Ocean features examples of three kinds of volcanic activity: mid-ocean ridge, near-ridge seamount, and intraplate seamount volcanism. Volcanism on the northern Juan de Fuca and Explorer ridges, at inter-transform pull-apart rifts, and at near-ridge seamounts close to the Juan de Fuca and Explorer ridges, produces lavas with unusually variable geochemical compositions. Lavas incorporate variable contributions from both trace-element-depleted upper mantle and trace-element-enriched veins, blobs or streaks embedded in the depleted upper mantle. The latter may have originated as dispersed parts of ancient mantle plumes similar to a modern plume responsible for the formation of the intraplate Bowie Seamount. SOMMAIRE Les fonds océaniques de la Zone économique exclusive du Canada de la région nord-est du Pacifique montrent des exemples de trois types d’activité volcanique : volcanisme de dorsale médio-océanique, de monts sousmarins de dorsale, et de monts sousmarins d’intra-plaque. Le volcanisme de la dorsale Explorer et de la portion nord de la dorsale de Juan de Fuca, au droit des rifts d’extension de failles inter-transformantes, et non loin des monts sous-marins jouxtant la dorsale Explorer et celle de Juan de Fuca produisent des laves de composition géochimique anormalement variable. Les laves renferment des quantités variables de matériaux du manteau supérieur appauvris en éléments traces mais aussi de filons enrichis en éléments traces, en amas ou traînées ennoyés dans le manteau supérieur. Ces derniers peuvent provenir de reliquats d’anciens panaches mantelliques similaires aux panaches modernes à l’origine de la formation du mont sous-marin de Bowie

Radiogenic isotopes in enriched mid-ocean ridge basalts from Explorer Ridge, northeast Pacific Ocean

Extreme gradients in topography related to variations in magma supply are observed on the Southern Explorer Ridge (SER), part of the northern Juan de Fuca ridge system. We report radiogenic isotope (Pb, Sr, Nd, Hf) and geochemical data for twenty-four basalt whole-rock and glass samples collected from the length of the SER and from Explorer Deep, a rift to the north of the SER. Lavas from the SER form a north-south geochemical gradient, dominated by E-MORB at the northern axial high, and range from T-MORB to N-MORB towards the southern deepest part of the ridge. Linear relationships between incompatible element ratios and isotopic ratios in MORB along the ridge are consistent with mixing of magmas beneath the ridge to generate the geographic gradient from E- to N-MORB. The E-MORB have high Sr and Pb, and low Nd and Hf isotopic ratios, typical of enriched mantle that includes a FOZO or HIMU isotopic component. The West Valley and Endeavour segments of the northern Juan de Fuca ridge also include this isotopic component, but the proportion of the FOZO or HIMU component is more extreme in the SER basalts. The FOZO or HIMU component may be garnet-bearing peridotite, or a garnet pyroxenite embedded in peridotite. Recycled garnet pyroxenite better explains the very shallow SER axial high, high Nb/La and La/Sm, and the “enriched” isotopic compositions

Intermittent preventive treatment of malaria provides substantial protection against malaria in children already protected by an insecticide-treated bednet in Burkina Faso: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Intermittent preventive treatment of malaria in children (IPTc) is a promising new approach to the control of malaria in areas of seasonal malaria transmission but it is not known if IPTc adds to the protection provided by an insecticide-treated net (ITN). METHODS AND FINDINGS: An individually randomised, double-blind, placebo-controlled trial of seasonal IPTc was conducted in Burkina Faso in children aged 3 to 59 months who were provided with a long-lasting insecticide-treated bednet (LLIN). Three rounds of treatment with sulphadoxine pyrimethamine plus amodiaquine or placebos were given at monthly intervals during the malaria transmission season. Passive surveillance for malaria episodes was established, a cross-sectional survey was conducted at the end of the malaria transmission season, and use of ITNs was monitored during the intervention period. Incidence rates of malaria were compared using a Cox regression model and generalized linear models were fitted to examine the effect of IPTc on the prevalence of malaria infection, anaemia, and on anthropometric indicators. 3,052 children were screened and 3,014 were enrolled in the trial; 1,505 in the control arm and 1,509 in the intervention arm. Similar proportions of children in the two treatment arms were reported to sleep under an LLIN during the intervention period (93%). The incidence of malaria, defined as fever or history of fever with parasitaemia ≥ 5,000/µl, was 2.88 (95% confidence interval [CI] 2.70-3.06) per child during the intervention period in the control arm versus 0.87 (95% CI 0.78-0.97) in the intervention arm, a protective efficacy (PE) of 70% (95% CI 66%-74%) (p<0.001). There was a 69% (95% CI 6%-90%) reduction in incidence of severe malaria (p = 0.04) and a 46% (95% CI 7%-69%) (p = 0.03) reduction in the incidence of all-cause hospital admissions. IPTc reduced the prevalence of malaria infection at the end of the malaria transmission season by 73% (95% CI 68%-77%) (p<0.001) and that of moderately severe anaemia by 56% (95% CI 36%-70%) (p<0.001). IPTc reduced the risks of wasting (risk ratio [RR] = 0.79; 95% CI 0.65-1.00) (p = 0.05) and of being underweight (RR = 0.84; 95% CI 0.72-0.99) (p = 0.03). Children who received IPTc were 2.8 (95% CI 2.3-3.5) (p<0.001) times more likely to vomit than children who received placebo but no drug-related serious adverse event was recorded. CONCLUSIONS: IPT of malaria provides substantial protection against malaria in children who sleep under an ITN. There is now strong evidence to support the integration of IPTc into malaria control strategies in areas of seasonal malaria transmission. TRIAL REGISTRATION: ClinicalTrials.govNCT00738946. Please see later in the article for the Editors' Summary

Effect on Neonatal Mortality of Newborn Infection Management at Health Posts When Referral Is Not Possible: A Cluster-Randomized Trial in Rural Ethiopia.

BACKGROUND: The World Health Organization recently provided guidelines for outpatient treatment of possible severe bacterial infections (PSBI) in young infants, when referral to hospital is not feasible. This study evaluated newborn infection treatment at the most peripheral level of the health system in rural Ethiopia. METHODS: We performed a cluster-randomized trial in 22 geographical clusters (11 allocated to intervention, 11 to control). In both arms, volunteers and government-employed Health Extension Workers (HEWs) conducted home visits to pregnant and newly delivered mothers; assessed newborns; and counseled caregivers on prevention of newborn illness, danger signs, and care seeking. Volunteers referred sick newborns to health posts for further assessment; HEWs referred newborns with PSBI signs to health centers. In the intervention arm only, between July 2011 and June 2013, HEWs treated newborns with PSBI with intramuscular gentamicin and oral amoxicillin for 7 days at health posts when referral to health centers was not possible or acceptable to caregivers. Intervention communities were informed of treatment availability at health posts to encourage care seeking. Masking was not feasible. The primary outcome was all-cause mortality of newborns 2-27 days after birth, measured by household survey data. Baseline data were collected between June 2008 and May 2009; endline data, between February 2013 and June 2013. We sought to detect a 33% mortality reduction. Analysis was by intention to treat. (ClinicalTrials.gov registry: NCT00743691). RESULTS: Of 1,011 sick newborns presenting at intervention health posts, 576 (57%) were identified by HEWs as having at least 1 PSBI sign; 90% refused referral and were treated at the health post, with at least 79% completing the antibiotic regimen. Estimated treatment coverage at health posts was in the region of 50%. Post-day 1 neonatal mortality declined more in the intervention arm (17.9 deaths per 1,000 live births at baseline vs. 9.4 per 1,000 at endline) than the comparison arm (14.4 per 1,000 vs. 11.2 per 1,000, respectively). After adjusting for baseline mortality and region, the estimated post-day 1 mortality risk ratio was 0.83, but the result was not statistically significant (95% confidence interval, 0.55 to 1.24; P=.33). INTERPRETATION: When referral to higher levels of care is not possible, HEWs can deliver outpatient antibiotic treatment of newborns with PSBI, but estimated treatment coverage in a rural Ethiopian setting was only around 50%. While our data suggest a mortality reduction consistent with that which might be expected at this level of coverage, they do not provide conclusive results

Intermittent preventive treatment of malaria provides substantial protection against malaria in children already protected by an insecticide-treated bednet in Mali: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Previous studies have shown that in areas of seasonal malaria transmission, intermittent preventive treatment of malaria in children (IPTc), targeting the transmission season, reduces the incidence of clinical malaria. However, these studies were conducted in communities with low coverage with insecticide-treated nets (ITNs). Whether IPTc provides additional protection to children sleeping under an ITN has not been established. METHODS AND FINDINGS: To assess whether IPTc provides additional protection to children sleeping under an ITN, we conducted a randomised, double-blind, placebo-controlled trial of IPTc with sulphadoxine pyrimethamine (SP) plus amodiaquine (AQ) in three localities in Kati, Mali. After screening, eligible children aged 3-59 mo were given a long-lasting insecticide-treated net (LLIN) and randomised to receive three rounds of active drugs or placebos. Treatments were administered under observation at monthly intervals during the high malaria transmission season in August, September, and October 2008. Adverse events were monitored immediately after the administration of each course of IPTc and throughout the follow-up period. The primary endpoint was clinical episodes of malaria recorded through passive surveillance by study clinicians available at all times during the follow-up. Cross-sectional surveys were conducted in 150 randomly selected children weekly and in all children at the end of the malaria transmission season to assess usage of ITNs and the impact of IPTc on the prevalence of malaria, anaemia, and malnutrition. Cox regression was used to compare incidence rates between intervention and control arms. The effects of IPTc on the prevalence of malaria infection and anaemia were estimated using logistic regression. 3,065 children were screened and 3,017 (1,508 in the control and 1,509 in the intervention arm) were enrolled in the study. 1,485 children (98.5%) in the control arm and 1,481 (98.1%) in the intervention arm completed follow-up. During the intervention period, the proportion of children reported to have slept under an ITN was 99.7% in the control and 99.3% in intervention arm (p = 0.45). A total of 672 episodes of clinical malaria defined as fever or a history of fever and the presence of at least 5,000 asexual forms of Plasmodium falciparum per microlitre (incidence rate of 1.90; 95% confidence interval [CI] 1.76-2.05 episodes per person year) were observed in the control arm versus 126 (incidence rate of 0.34; 95% CI 0.29-0.41 episodes per person year) in the intervention arm, indicating a protective effect (PE) of 82% (95% CI 78%-85%) (p<0.001) on the primary endpoint. There were 15 episodes of severe malaria in children in the control arm compared to two in children in the intervention group giving a PE of 87% (95% CI 42%-99%) (p = 0.001). IPTc reduced the prevalence of malaria infection by 85% (95% CI 73%-92%) (p<0.001) during the intervention period and by 46% (95% CI 31%-68%) (p<0.001) at the end of the intervention period. The prevalence of moderate anaemia (haemoglobin [Hb] <8 g/dl) was reduced by 47% (95% CI 15%-67%) (p<0.007) at the end of intervention period. The frequencies of adverse events were similar between the two arms. There was no drug-related serious adverse event. CONCLUSIONS: IPTc given during the malaria transmission season provided substantial protection against clinical episodes of malaria, malaria infection, and anaemia in children using an LLIN. SP+AQ was safe and well tolerated. These findings indicate that IPTc could make a valuable contribution to malaria control in areas of seasonal malaria transmission alongside other interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT00738946. Please see later in the article for the Editors' Summary

National, regional, and state-level all-cause and cause-specific under-5 mortality in India in 2000-15: a systematic analysis with implications for the Sustainable Development Goals.

BACKGROUND: India had the largest number of under-5 deaths of all countries in 2015, with substantial subnational disparities. We estimated national and subnational all-cause and cause-specific mortality among children younger than 5 years annually in 2000-15 in India to understand progress made and to consider implications for achieving the Sustainable Development Goal (SDG) child survival targets. METHODS: We used a multicause model to estimate cause-specific mortality proportions in neonates and children aged 1-59 months at the state level, with causes of death grouped into pneumonia, diarrhoea, meningitis, injury, measles, congenital abnormalities, preterm birth complications, intrapartum-related events, and other causes. AIDS and malaria were estimated separately. The model was based on verbal autopsy studies representing more than 100 000 neonatal deaths globally and 16 962 deaths among children aged 1-59 months at the subnational level in India. By applying these proportions to all-cause deaths by state, we estimated cause-specific numbers of deaths and mortality rates at the state, regional, and national levels. FINDINGS: In 2015, there were 25·121 million livebirths in India and 1·201 million under-5 deaths (under-5 mortality rate 47·81 per 1000 livebirths). 0·696 million (57·9%) of these deaths occurred in neonates. There were disparities in child mortality across states (from 9·7 deaths [Goa] to 73·1 deaths [Assam] per 1000 livebirths) and regions (from 29·7 deaths [the south] to 63·8 deaths [the northeast] per 1000 livebirths). Overall, the leading causes of under-5 deaths were preterm birth complications (0·330 million [95% uncertainty range 0·279-0·367]; 27·5% of under-5 deaths), pneumonia (0·191 million [0·168-0·219]; 15·9%), and intrapartum-related events (0·139 million [0·116-0·165]; 11·6%), with cause-of-death distributions varying across states and regions. In states with very high under-5 mortality, infectious-disease-related causes (pneumonia and diarrhoea) were among the three leading causes, whereas the three leading causes were all non-communicable in states with very low mortality. Most states had a slower decline in neonatal mortality than in mortality among children aged 1-59 months. Ten major states must accelerate progress to achieve the SDG under-5 mortality target, while 17 are not on track to meet the neonatal mortality target. INTERPRETATION: Efforts to reduce vaccine-preventable deaths and to reduce geographical disparities should continue to maintain progress achieved in 2000-15. Enhanced policies and programmes are needed to accelerate mortality reduction in high-burden states and among neonates to achieve the SDG child survival targets in India by 2030. FUNDING: Bill & Melinda Gates Foundation

Major and trace element geochemistry of basalts from the Explorer area, Northeast Pacific Ocean

Fifty fragments of young, fresh basalts from the Explorer Ridge, Paul Revere Ridge (Fracture Zone), Dellwood Knolls, and the J. Tuzo Wilson Knolls have been analysed for 12 major and minor elements, as well as 11 trace elements, by X-ray fluorescence spectrometry. Rare earth element concentrations in 25 of the samples have been determined by instrumental neutron activation, and Sr⁸⁷/Sr⁸⁶ ratios have been obtained for 11 of the basalts. The Explorer Ridge basalts have major element compositions similar to most mid-ocean ridge basalts (MORB), and can be classified as ferrobasalts, similar to those of the southern Juan de Fuca Ridge. The incompatible minor and trace elements K, Ti, Rb, Zr, and Nb are weakly to strongly enriched in the Explorer samples, with respect to MORB, part of which is the result of crystal fractionation. The observed trace element and light rare earth element (LREE) enrichment of many of the samples, particularly those from Explorer Deep, suggest that a weak hotspot may exist beneath the Explorer Deep. The adjacent ridge segments, Explorer Rift and the Southern Explorer Ridge, are erupting basalts both enriched and depleted in incompatible elements, which could be an indicator of a chemically heterogenous mantle source, or may be the result of intermittent injection of enriched magmas from the postulated hotspot beneath Explorer Deep into areas producing normal MORB. The enriched basalts do not have significantly different Sr⁸⁷/Sr⁸⁶ ratios from the depleted basalts. All the samples fall within the range of values typical for Juan de Fuca and Gorda Ridge basalts, and East Pacific Rise tholeiites in general. Thus, although the source areas for the 2 basalt types may differ chemically, they are similar radiogenically, unlike-other hypothetically plume-influenced areas such as the Mid-Atlantic Ridge at 45°N and the FAMOUS area. The basalts from the northwest and southeast Dellwood Knolls appear to be related by crystal fractionation, based on major element analysis. However, the very different REE patterns and Sr⁸⁷/Sr⁸⁶ ratios exhibited by the two knolls suggest that they have different mantle sources, one typically depleted (northwest knoll) and one chemically and radiogenically enriched (southeast knoll). In terms of their major and trace element chemistry, the J. Tuzo Wilson Knolls basalts are typical of late-stage volcanism on ocean islands associated with mantle plumes. The hawaiites strongly resemble alkali basalts dredged from several seamounts in the Pratt-Welker Chain, which are co-latitudinal with the J. Tuzo Wilson Knolls on a small circle about the Pacific-Hotspot pole of rotation. Geochronological evidence questions the hypothesis that the mantle plume responsible for Pratt-Welker volcanism is also the source for the J. Tuzo Wilson basalts. The existence of a second mantle plume, 300 km southeast of the first, would explain minor chemical and physiographical differences between the Knolls and the other Pratt-Welker seamounts, as well as the evidence for two phases of volcanism on the southeastern seamounts of the chain. A second plume also explains the coeval volcanism of Bowie Seamount and the J. Tuzo Wilson Knolls. Recent geophysical evidence suggests that the J. Tuzo Wilson Knolls are also part of the Explorer-Dellwood spreading system. Although the JTW basalts are plume-type basalts chemically, the situation appears to be somewhat analagous to other ridge segments where plumes are coincident with the ridge itself.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat