Addressing the challenge of neonatal mortality.

Reducing neonatal mortality remains a challenge with an estimated 3.0 million neonatal deaths in 2011, three-quarters of these in sub-Saharan Africa and Southern Asia. The leading causes of neonatal death globally are complications of preterm birth, intrapartum-related causes and infections. While post-neonatal, under-5 deaths fell by 47% between 1990 and 2011, neonatal deaths only fell by 32% and they now account for 43% of all under-5 child deaths. This article reviews the progress in reducing neonatal deaths in high-burden countries and presents an overview of known effective interventions to reduce neonatal mortality and the challenges faced in implementing these in high-burden settings. Effective action is possible to reduce neonatal mortality, but innovative approaches to implementation will be required if these preventable deaths are to be avoided

Counting the smallest: data to estimate global stillbirth, preterm birth and low birthweight rates

Background: Stillbirth, preterm birth and low birthweight are important indicators of global burden of disease, status of maternal health and healthcare, and predictors of health throughout the life-course. Data are available through Civil Registration and Vital Statistics (CRVS), Health Management Information Systems (HMIS) and household surveys. Comparisons of data by country or over time requires standard definitions and comparable data quality. Data gaps and inconsistencies necessitate adjustments and use of modelled estimates in many settings. Methods: Systematic data searches were undertaken to compile available data on these outcomes for 195 countries. Where no reliable data were available, statistical models were used to generate national estimates. Data quantity and quality were summarised for each outcome, with implications for improvement and research. Results: The estimated burden remains large: 2.6 million stillbirths (2015), 14.9 million preterm births (2010) and 20.5 million low birthweight babies (2015) based on 4,392 data-points from 148 countries. Common data quality challenges include use of non-standard definitions, omission, and misclassification. Targeted data quality assessments are required to detect these. Five data gaps identified to address are: (1) coverage of data systems (2) accurate assessment of vital status at birth, birthweight and gestational age for every birth, (3) accurate recording of these key data elements (4) comparable collation within and across data systems and (5) use of data to inform programmes and policy. Evidence exists across all data platforms of examples of solutions to close these gaps. Systematic data linkage could increase efficiency. Conclusion: Data availability has increased over the last decade, even in the poorest countries. Data quality issues currently hamper the use of these data to improve outcomes in many settings, but could be addressed with political will and targeted investment. Ending preventable deaths among the world’s smallest babies requires that these data are accurate, available and used

Dynamics of a nanomechanical resonator coupled to a superconducting single-electron transistor

We present an analysis of the dynamics of a nanomechanical resonator coupled to a superconducting single electron transistor (SSET) in the vicinity of the Josephson quasiparticle (JQP) and double Josephson quasiparticle (DJQP) resonances. For weak coupling and wide separation of dynamical timescales, we find that for either superconducting resonance the dynamics of the resonator is given by a Fokker-Planck equation, i.e., the SSET behaves effectively as an equilibrium heat bath, characterised by an effective temperature, which also damps the resonator and renormalizes its frequency. Depending on the gate and drain-source voltage bias points with respect to the superconducting resonance, the SSET can also give rise to an instability in the mechanical resonator marked by negative damping and temperature within the appropriate Fokker-Planck equation. Furthermore, sufficiently close to a resonance, we find that the Fokker-Planck description breaks down. We also point out that there is a close analogy between coupling a nanomechanical resonator to a SSET in the vicinity of the JQP resonance and Doppler cooling of atoms by means of lasers

Quantum master equation descriptions of a nanomechanical resonator coupled to a single-electron transistor

We analyse the quantum dynamics of a nanomechanical resonator coupled to a normal-state single-electron transistor (SET). Starting from a microscopic description of the system, we derive a master equation for the SET island charge and resonator which is valid in the limit of weak electro-mechanical coupling. Using this master equation we show that, apart from brief transients, the resonator always behaves like a damped harmonic oscillator with a shifted frequency and relaxes into a thermal-like steady state. Although the behaviour remains qualitatively the same, we find that the magnitude of the resonator damping rate and frequency shift depend very sensitively on the relative magnitudes of the resonator period and the electron tunnelling time. Maximum damping occurs when the electrical and mechanical time-scales are the same, but the frequency shift is greatest when the resonator moves much more slowly than the island charge. We then derive reduced master equations which describe just the resonator dynamics. By making slightly different approximations, we obtain two different reduced master equations for the resonator. Apart from minor differences, the two reduced master equations give rise to a consistent picture of the resonator dynamics which matches that obtained from the master equation including the SET island charge.Comment: 22 pages, 4 figure

The effect of coverings, including plastic bags and wraps, on mortality and morbidity in preterm and full-term neonates.

Neonatal hypothermia is an important risk factor for mortality and morbidity, and is common even in temperate climates. We conducted a systematic review to determine whether plastic coverings, used immediately following delivery, were effective in reducing the incidence of mortality, hypothermia and morbidity. A total of 26 studies (2271 preterm and 1003 term neonates) were included. Meta-analyses were conducted as appropriate. Plastic wraps were associated with a reduction in hypothermia in preterm (⩽29 weeks; risk ratio (RR)=0.57; 95% confidence interval (CI) 0.46 to 0.71) and term neonates (RR=0.76; 95% CI 0.60 to 0.96). No significant reduction in neonatal mortality or morbidity was found; however, the studies were underpowered for these outcomes. For neonates, especially preterm, plastic wraps combined with other environmental heat sources are effective in reducing hypothermia during stabilization and transfer within hospital. Further research is needed to quantify the effects on mortality or morbidity, and investigate the use of plastic coverings outside hospital settings or without additional heat sources

Stillbirth should be given greater priority on the global health agenda

Stillbirths are largely excluded from international measures of mortality and morbidity. Zeshan Qureshi and colleagues argue that stillbirth should be higher on the global health agenda

The Effect of Surface Roughness on the Universal Thermal Conductance

We explain the reduction of the thermal conductance below the predicted universal value observed by Schwab et al. in terms of the scattering of thermal phonons off surface roughness using a scalar model for the elastic waves. Our analysis shows that the thermal conductance depends on two roughness parameters: the roughness amplitude $\delta$ and the correlation length $a$. At sufficiently low temperatures the conductance decrease from the universal value quadratically with temperature at a rate proportional to $\delta ^{2}a$. Values of $\delta$ equal to 0.22 and $a$ equal to about 0.75 of the width of the conduction pathway give a good fit to the data.Comment: 10 pages, 5 figures. Ref. added, typo correcte

Quantum dynamics of a Josephson junction driven cavity mode system in the presence of voltage bias noise

We give a semiclassical analysis of the average photon number as well as photon number variance (Fano factor F) for a Josephson junction (JJ) embedded microwave cavity system, where the JJ is subject to a fluctuating (i.e., noisy) bias voltage with finite dc average. Through the ac Josephson effect, the dc voltage bias drives the effectively nonlinear microwave cavity mode into an amplitude squeezed state (F <1), as has been established previously [Armour et al., Phys. Rev. Lett. 111, 247001 (2013)], but bias noise acts to degrade this squeezing. We find that the sensitivity of the Fano factor to bias voltage noise depends qualitatively on which stable fixed point regime the system is in for the corresponding classical nonlinear steady-state dynamics. Furthermore, we show that the impact of voltage bias noise is most significant when the cavity is excited to states with large average photon number

Transcriptomic analysis of autistic brain reveals convergent molecular pathology.

Autism spectrum disorder (ASD) is a common, highly heritable neurodevelopmental condition characterized by marked genetic heterogeneity. Thus, a fundamental question is whether autism represents an aetiologically heterogeneous disorder in which the myriad genetic or environmental risk factors perturb common underlying molecular pathways in the brain. Here, we demonstrate consistent differences in transcriptome organization between autistic and normal brain by gene co-expression network analysis. Remarkably, regional patterns of gene expression that typically distinguish frontal and temporal cortex are significantly attenuated in the ASD brain, suggesting abnormalities in cortical patterning. We further identify discrete modules of co-expressed genes associated with autism: a neuronal module enriched for known autism susceptibility genes, including the neuronal specific splicing factor A2BP1 (also known as FOX1), and a module enriched for immune genes and glial markers. Using high-throughput RNA sequencing we demonstrate dysregulated splicing of A2BP1-dependent alternative exons in the ASD brain. Moreover, using a published autism genome-wide association study (GWAS) data set, we show that the neuronal module is enriched for genetically associated variants, providing independent support for the causal involvement of these genes in autism. In contrast, the immune-glial module showed no enrichment for autism GWAS signals, indicating a non-genetic aetiology for this process. Collectively, our results provide strong evidence for convergent molecular abnormalities in ASD, and implicate transcriptional and splicing dysregulation as underlying mechanisms of neuronal dysfunction in this disorder