A survey of the levels of lightning and thunderstorm activity in Sierra Leone

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An ultraviolet excess in the superluminous supernova Gaia16apd reveals a powerful central engine

Since the discovery of superluminous supernovae (SLSNe) in the last decade, it has been known that these events exhibit bluer spectral energy distributions than other supernova subtypes, with significant output in the ultraviolet. However, the event Gaia16apd seems to outshine even the other SLSNe at rest-frame wavelengths below $\sim 3000$ \AA. Yan et al (2016) have recently presented HST UV spectra and attributed the UV flux to low metallicity and hence reduced line blanketing. Here we present UV and optical light curves over a longer baseline in time, revealing a rapid decline at UV wavelengths despite a typical optical evolution. Combining the published UV spectra with our own optical data, we demonstrate that Gaia16apd has a much hotter continuum than virtually any SLSN at maximum light, but it cools rapidly thereafter and is indistinguishable from the others by $\sim 10$-15 days after peak. Comparing the equivalent widths of UV absorption lines with those of other events, we show that the excess UV continuum is a result of a more powerful central power source, rather than a lack of UV absorption relative to other SLSNe or an additional component from interaction with the surrounding medium. These findings strongly support the central-engine hypothesis for hydrogen-poor SLSNe. An explosion ejecting $M_{\rm ej} = 4 (0.2/\kappa)$ M$_\odot$, where $\kappa$ is the opacity in cm$^2$g$^{-1}$, and forming a magnetar with spin period $P=2$ ms, and $B=2\times10^{14}$ G (lower than other SLSNe with comparable rise-times) can consistently explain the light curve evolution and high temperature at peak. The host metallicity, $Z=0.18$ Z$_\odot$, is comparable to other SLSNe.Comment: Updated to match accepted version (ApJL

Empirical constraints on the origin of fast radio bursts: volumetric rates and host galaxy demographics as a test of millisecond magnetar connection

The localization of the repeating FRB 121102 to a low-metallicity dwarf galaxy at $z=0.193$, and its association with a quiescent radio source, suggests the possibility that FRBs originate from magnetars, formed by the unusual supernovae in such galaxies. We investigate this via a comparison of magnetar birth rates, the FRB volumetric rate, and host galaxy demographics. We calculate average volumetric rates of possible millisecond magnetar production channels such as superluminous supernovae (SLSNe), long and short gamma-ray bursts (GRBs), and general magnetar production via core-collapse supernovae. For each channel we also explore the expected host galaxy demographics using their known properties. We determine for the first time the number density of FRB emitters (the product of their volumetric birthrate and lifetime), $R_{\rm FRB}\tau\approx 10^4$Gpc$^{-3}$, assuming that FRBs are predominantly emitted from repetitive sources similar to FRB 121102 and adopting a beaming factor of 0.1. By comparing rates we find that production via rare channels (SLSNe, GRBs) implies a typical FRB lifetime of $\approx$30-300 yr, in good agreement with other lines of argument. The total energy emitted over this time is consistent with the available energy stored in the magnetic field. On the other hand, any relation to magnetars produced via normal core-collapse supernovae leads to a very short lifetime of $\approx$0.5yr, in conflict with both theory and observation. We demonstrate that due to the diverse host galaxy distributions of the different progenitor channels, many possible sources of FRB birth can be ruled out with $\lesssim 10$ host galaxy identifications. Conversely, targeted searches of galaxies that have previously hosted decades-old SLSNe and GRBs may be a fruitful strategy for discovering new FRBs and related quiescent radio sources, and determining the nature of their progenitors

Outcomes of breech birth by mode of delivery: a population linkage study

Background: Trial evidence supports a policy of caesarean section for singleton breech presentations at term but vaginal breech birth is considered a safe option for selected women. Aims: To provide recent Australian data on outcomes associated with intended mode of delivery for term breech singletons in women who meet conservative eligibility criteria for vaginal breech birth. Materials and Methods: Birth and hospital records from 2009 to 2012 in New South Wales were used to identify women with non-anomalous pregnancies who would be considered eligible for vaginal breech birth. Intended mode of delivery was inferred from labour onset and management. Results: Of 10,133 women with term breech singleton pregnancies, 5,197 (51.3%) were classified as eligible for vaginal breech delivery. Of these, 6.8% intended vaginal breech birth, 76.4% planned caesarean section, and intention could not be determined for 16.8%. Women intending vaginal delivery had higher rates of neonatal morbidity (6.0% vs. 2.1%), neonatal birth trauma (7.4% vs. 0.9%), Apgar <4 at 1 minute (10.5% vs. 1.1%), Apgar<7 at 5 minutes (4.3% vs. 0.5%), and NICU/SCN admissions (16.2% vs. 6.6%) than those planning caesarean section. Increased perinatal risks remained after adjustment for maternal characteristics. Severe maternal morbidity (1.4% vs. 0.7%) and postpartum readmission (4.6% vs. 4.0%) were higher in the intended vaginal compared to planned caesarean births but these differences were not statistically significant. Conclusions: In a population of women classified as being eligible for vaginal breech birth, intended vaginal delivery was associated with higher rates of neonatal morbidity than planned caesarean section.NHMRC, AR

Contribution of Changing Risk Factors to the Trend in Breech Presentation at Term

Background: Recent population-wide changes in perinatal risk factors may affect rates of breech presentation at birth, and have implications for the provision of breech services and clinical training in breech management. Aims: To determine the trend in breech presentation at term and investigate whether changes in maternal and pregnancy characteristics explain the observed trend. Materials and Methods: All singleton term (≥37 week) births in New South Wales during 2002 – 2012 were identified through birth and associated hospital records. Annual rates of breech presentation were determined. Logistic regression modelling was used to predict expected rates of breech presentation over time and these were compared with observed rates. A priori predictors included maternal age, country of birth, parity, smoking during pregnancy, diabetes, pregnancy hypertension, placenta praevia, previous singleton term breech, previous caesarean section, infant sex, gestational age, birthweight, and congenital anomalies. Hospital and Medicare data were used to assess trends in external cephalic version. Results: Among 914,147 singleton term births, 3.1% were breech at delivery. Rates declined from 3.6% in 2002 to 2.7% in 2012 (test for trend p<0.001). Breech presentation was predicted to increase from 3.6% in 2002 to 4.3% in 2012 because of increased maternal age, nulliparity, maternal diabetes, history of breech presentation and previous caesarean section. Use of external cephalic version appears to have increased over time. Conclusions: Breech presentation at delivery has decreased in New South Wales. Increased use of external cephalic version likely accounts for this decline, as changes in risk factors do not.NHMRC, AR

Pharmacological characterization of the excitatory ‘Cys‐loop’ GABA receptor family in Caenorhabditis elegans

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136449/1/bph13736.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136449/2/bph13736_am.pd

MOSFiT: Modular open source fitter for transients

Much of the progress made in time-domain astronomy is accomplished by relating observational multi-wavelength time series data to models derived from our understanding of physical laws. This goal is typically accomplished by dividing the task in two: collecting data (observing), and constructing models to represent that data (theorizing). Owing to the natural tendency for specialization, a disconnect can develop between the best available theories and the best available data, potentially delaying advances in our understanding new classes of transients. We introduce MOSFiT: the Modular Open-Source Fitter for Transients, a Python-based package that downloads transient datasets from open online catalogs (e.g., the Open Supernova Catalog), generates Monte Carlo ensembles of semi-analytical light curve fits to those datasets and their associated Bayesian parameter posteriors, and optionally delivers the fitting results back to those same catalogs to make them available to the rest of the community. MOSFiT is designed to help bridge the gap between observations and theory in time-domain astronomy; in addition to making the application of existing models and creation of new models as simple as possible, MOSFiT yields statistically robust predictions for transient characteristics, with a standard output format that includes all the setup information necessary to reproduce a given result. As large-scale surveys such as LSST discover entirely new classes of transients, tools such as MOSFiT will be critical for enabling rapid comparison of models against data in statistically consistent, reproducible, and scientifically beneficial ways

Rate of spontaneous onset of labour before planned repeat caesarean section at term

In an auditory lexical decision experiment, 5,541 spoken content words and pseudo-words were presented to 20 native speakers of Dutch. The words vary in phonological makeup and in number of syllables and stress pattern, and are further representative of the native Dutch vocabulary in that most are morphologically complex, comprising two stems or one stem plus derivational and inflectional suffixes, with inflections representing both regular and irregular paradigms; the pseudo-words were matched in these respects to the real words. The BALDEY data file includes response times and accuracy rates, with for each item morphological information plus phonological and acoustic information derived from automatic phonemic segmentation of the stimuli. Two initial analyses illustrate how this data set can be used. First, we discuss several measures of the point at which a word has no further neighbors, and compare the degree to which each measure predicts our lexical decision response outcomes. Second, we investigate how well four different measures of frequency of occurrence (from written corpora, spoken corpora, subtitles and frequency ratings by 70 participants) predict the same outcomes. These analyses motivate general conclusions about the auditory lexical decision task. The (publicly available) BALDEY database lends itself to many further analyses