Comparison of the eighth edition of the TNM and Brigham Women's Hospital staging systems for cutaneous squamous cell carcinoma of the head and neck: a six-year review

This study was undertaken with the aim to compare the T stages in a series of cutaneous squamous cell carcinoma (cSCC) patients using both the eighth edition of the Union for International Cancer Control (UICC) TNM Classification of Malignant Tumours (TNM8) and Brigham and Women's Hospital (BWH) staging systems. This would allow comparison of the two to determine suitability with regards to T stage and the effect on local recurrence and nodal disease. This was a six-year retrospective cohort study of patients with primary invasive cSCC of the head and neck who were diagnosed and treated at Western Sussex Hospitals Trust in the United Kingdom between 2007 and 2012. The TNM8 and BWH staging systems were applied to these primary cSCCs. A total of 695 invasive cSCCs treated in 604 patients over six years were identified. Most patients were male (76%), with a mean (range) age of 81 (50-103) years. The most common location for local recurrence was the scalp (n=26, 58%). Regional metastasis occurred most commonly in the parotid gland (n=20, 63%). All tumours were classified using both staging systems. Specifically, 432 tumours remained in the same T stage (61%), and 192 were downstaged (27%) and 71 upstaged using the BWH (10%). The median (SD) follow-up time was 23 (28) months (range 1-123). The BWH alternative staging system overlapped with the TNM8 in high-stage and low-stage tumour assignment. The highest percentage of local recurrence and regional metastasis occurred in T2b tumours.

Provision of Emergency Maxillofacial Service During the COVID-19 Pandemic : A Collaborative Five Centre UK Study

The global pandemic of Coronavirus disease (COVID-19) represents one of the greatest challenges to healthcare systems, and has forced medical specialties to rapidly adapt their approaches to patient care. Oral and Maxillofacial Surgery is considered particularly at risk of disease transmission due to aerosol generation during surgical interventions, patient proximity and operating environment. On day 2 (26th March, 2020) of when severe restrictions in population movement were instigated in the United Kingdom, we began a study to prospectively monitor the presentation and management of maxillofacial emergencies at five hospital trusts. Data was collected onto an online live database fed through a smartphone application. Of the total 529 patients over six weeks, 395 attended for face-to-face consultations and 134 patients received remote consultations via telephone or video link. There were 255 trauma related cases, 221 infection and 48 cases of postoperative complications. Most trauma cases were minor soft tissue injury related to slip, trip or fall at home. There were 44 cases of facial fractures with a tendency for conservative treatment. 19 cases were related to domestic violence or self-harm. Of the 216 dental related emergencies, 68% could have been managed in the primary care setting. A quarter of all emergency patients were satisfactorily managed by remote consultations. There was a significant change in the provision of emergency maxillofacial service during the pandemic lockdown. We discuss the study findings as well as the potential implications in relation to planning for possible further COVID- 19 spikes and future pandemics.

Health-related quality of life following breast reconstruction compared to total mastectomy and breast-conserving surgery among breast cancer survivors: a systematic review and meta-analysis

The present review evaluated health-related quality of life (HR-QoL) outcomes in surgical breast cancer survivors who received breast reconstruction (BR), breast-conservation surgery (BCS) or mastectomy (M), and whether HR-QoL domains across generic and disease/surgery-specific questionnaires are compatible. Six electronic databases were searched for appropriate observational studies. Standardized scores for different HR-QoL domains in the BR, BCS, and M treatment groups were extracted from each study for the purpose of a meta-analysis. Using Stata version 14.0, a random-effects meta-analysis model was adopted for each outcome variable to estimate the effect size, 95% CI-confidence intervals, and statistical significance. Sixteen of the 18 eligible studies with BR (n = 1474) and BCS (n = 2612) or M (n = 1458) groups were included in the meta-analysis. The BR group exhibited a better physical health (k = 12; 0.1, 95% CI 0.04, 0.24) and body image (k = 12; 0.50, 95% CI 0.10, 0.89) than the M group. However, the two groups exhibited comparable social health (k = 13; 0.1, 95% CI -0.07, 0.37), emotional health (k = 13; -0.08, 95% CI - 0.41, 0.25), global health (k = 7; 0.1, 95% CI - 0.01, 0.27), and sexual health (k =11; 0.2, 95% CI - 0.02,0.57). There was no clear evidence of the superiority of BR to BCS for all the six domains. These results suggest that HR-QoL outcomes in BR and BCS groups are better than the M group. Therefore, women opting for BR or BCS are likely to report fairly better HR-QoL outcomes than M. However, due to the significant heterogeneity observed in most BR versus BCS outcomes, developing a unified questionnaire incorporating both breast/surgery-specific and generic HR-QoL domains is warranted.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

53 Transcriptomic profiles of uniform populations of invivo-produced spherical, ovoid, or tubular porcine embryos during the initiation of elongation

Signalling interactions among littermate porcine conceptuses during embryo elongation can alter the expression of genes that are essential in promoting successful embryo elongation. Understanding the differential expression of critical genes from uniform littermate conceptuses as they undergo the initiation of elongation can help identify critical pathways and genes to facilitate improved synchronization of embryo elongation and birthweight uniformity. The objective of this study was to identify differential gene expression from uniform porcine conceptuses as they transition through spherical (S), ovoid (O), and tubular (T) morphologies during the initiation of elongation invivo. White crossbred gilts (n=22) were bred at oestrus (designated as Day 0 of gestation) and harvested at Day 9, 10, or 11 of gestation to obtain corresponding uniform populations of each embryo morphology. Reproductive tracts were immediately collected and flushed with 40mL of RPMI-1640 medium. Based on morphology, embryos were assigned to one of three treatment groups: (1) uniform S (n=8); (2) uniform O (n=8); or (3) uniform T (n=6) in which at least 80% of the embryos within each litter corresponded to the latest stage morphology. RNA-Seq was performed from 22 libraries constructed from a single invivo-produced embryo from the uniform populations of S, O, or T embryos. Differentially expressed genes (DEG) and pathway analysis were evaluated using DESEqn 2 and iPathwayGuide, respectively. For the S vs. O comparison, 5726 DEG and 7 pathways were significantly enriched, including ribosome biogenesis, spliceosome, pyrimidine metabolism, RNA polymerase, one carbon pool by folate, ECM-receptor interaction, and MAPK signaling pathways. For the S vs. T comparison, 5914 DEG and 7 pathways were significantly enriched, including ribosome biogenesis, DNA replication, pyrimidine metabolism, cell cycle, mismatch repair, spliceosome, and one carbon pool by folate pathways. Interestingly, most of the transcripts in pathways involving DNA processing, nucleotide metabolism, transcription, and post-transcriptional modifications were upregulated in S embryos compared with O and T embryos. For the O vs. T comparison, only 20 DEG were identified and no pathways were found to be significant after FDR adjustment. These data illustrate dramatic changes in the transcriptomes from pre-elongation stage S embryos compared with transitional stage O and T embryos, and provide putative genes and pathways involved in internal signals for the initiation of embryo elongation in pigs. The USDA is an equal opportunity provider and employer. Funding was provided by USDA-NIFA-AFRI grant no. 2017-67015-26456.

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

Lymphomatoid papulosis: an update and review

Lymphomatoid papulosis (LyP) is a benign chronic often relapsing skin condition that belongs to the CD30-positive cutaneous lymphoproliferative disorders. LyP typically presents as crops of lesions with a tendency to self-resolve, and morphology can range from solitary to agminated or diffuse papules and plaques to nodules or tumours. The clinical-histological spectrum can range from borderline cases to overlap with primary cutaneous anaplastic cell lymphoma (pcALCL). Histology and immunophenotype commonly show overlap with other CD30-positive disorders and sometimes may be identical to pcALCL, making its diagnosis more difficult. Patients with LyP have an increased risk of developing a second neoplasm such as mycosis fungoides, pcALCL and/or Hodgkin lymphoma. Clinical correlation allows its proper classification and diagnosis, which is fundamental for treatment and prognosis. This review focuses on the clinical appearance, histopathological features, diagnosis, differential diagnosis and management of LyP.

278Clinical outcomes of state-of-the-art percutaneous coronary revascularization in patients with three-vessel disease: 3-year follow-up of the SYNTAX II study

Background

The clinical implication of state-of-art PCI at long term follow-up in patients with three vessel disease is undetermined.

Purpose

The purpose of the study was to investigate whether the favourable outcomes of state-of-the-art PCI in the SYNTAX-II trial, demonstrated up to 2 years, are maintained at 3-year follow-up.

Methods

The SYNTAX-II study was a multicentre, single arm study that investigated the impact of a state-of-art PCI strategy on clinical outcomes in patients with de novo three vessel coronary artery disease, without left main disease. State-of-art PCI includes: heart team decision-making utilizing the SYNTAX score II, hybrid iFR-FFR decision-making strategy, intravascular ultrasound guided stent implantation, contemporary chronic total occlusion revascularization techniques and guideline-directed medical therapy. The primary endpoint is major adverse cardiac and cerebrovascular events (MACCE – a composite of all-cause death, any stroke, myocardial infarction, or revascularization) at 3 years. Clinical outcomes in SYNTAX-II were compared to the predefined PCI (SYNTAX-I PCI) and coronary artery bypass graft (SYNTAX-I CABG) cohorts from the landmark SYNTAX Trial (SYNTAX-I), selected on the basis of equipoise for long-term (4-year) mortality utilising the SYNTAX Score II.

Results

Between February 2014 and November 2015, 454 patients out of 708 screened patients were enrolled in SYNTAX-II. In SYNTAX-I, 643 (58.8%) patients with 3VD without left main disease had an equipoise recommendation for CABG or PCI based on the SYNTAX Score II and were used as the comparator. At 2 years, MACCE rate in SYNTAX-II was significantly lower compared to SYNTAX-I PCI (13.2% vs. 21.9%, p=0.001). Furthermore, similar two-year outcomes for MACCE were evident between SYNTAX II-PCI and SYNTAX-I CABG (13.2 vs. 15.1%, p=0.42). Three-year results will be presented at ESC2019.

Conclusions

Three-year results of his study may offer an attractive option of revascularization strategy in predefined patients with de novo 3VD (SYNTAX Score II inclusion) even if the patients have moderate to severe anatomical complexity (anatomic SYNTAX score >22).

Acknowledgement/Funding

European Cardiovascular Research Institute (ECRI) with unrestricted research grants from Volcano and Boston Scientific

Malignant transformation of tailgut cysts is significantly higher than previously reported: systematic review of cases in the literature

AIM

The best treatment for tailgut cysts has not been firmly established. We report a systematic review of the cases in the available literature in order to provide an evidence base for treatment.

METHOD

A systematic search of articles wholly or partly in English was made of PubMed, Embase and Google Scholar; additional studies were discovered by searching reference lists and contacting authors directly. Search terms 'tailgut cyst', 'tail gut cyst', 'retrorectal hamartoma' and 'retrorectal tumour' were used for case reports or case series; no publication date restrictions were imposed. Only studies with histological confirmation of diagnosis and reporting the age and gender of patients were included. Papers were excluded by consensus between the first two authors.

RESULTS

A total of 196 individual cases were analysed in detail including 51 cases of neoplasia. The overall rate of neoplastic transformation was 26.6%. Although the male:female cyst incidence ratio was 1:4, men over 18 had a significantly greater relative risk of neoplasm at 1.94 (P = 0.0055). Radiological evidence of nodular thickening of the cyst wall significantly increased the relative risk of the presence of cancer (P = 0.0023).

CONCLUSIONS

Current orthodoxy that these are not dangerous embryological remnants is unfounded and may be false. The available data suggest the risk of malignant transformation is high and will apply to any residual tissue after excision. The same rationale behind total mesorectal excision in rectal cancer applies to tailgut cysts. Consequently they should be resected with similar oncological margins.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Health Outcomes of Youth in Clinical Pediatric Weight Management Programs in POWER

OBJECTIVE

To describe treatment outcomes of children and adolescents enrolled in the Pediatric Obesity Weight Evaluation Registry, a consortium of multicomponent pediatric weight management programs in the US.

STUDY DESIGN

This multicenter prospective observational cohort study, established in 2013, includes youth (2-18 years of age) with obesity enrolled from 31 Pediatric Obesity Weight Evaluation Registry (POWER) sites over a 2-year period and followed up to 12 months. Weight status was evaluated by the percentage of the 95th percentile for body mass index (%BMIp95). Associations of weight status outcomes with patient characteristics and program exposure were analyzed with multivariable mixed effects modeling.

RESULTS

We included 6454 children and adolescents (median age, 11 years; IQR, 9-14 years; 53% white, 32% Hispanic; 73% with severe obesity) who were enrolled in POWER. Median changes in %BMIp95 for this cohort were -1.88 (IQR, -5.8 to 1.4), -2.50 (IQR, -7.4 to 1.8), -2.86 (IQR, -8.7 to 1.9), at 4-6, 7-9, and 10-12 of months follow-up, respectively (all P < .05). Older age (≥12 years), greater severity of obesity, and Hispanic race/ethnicity were associated with better improvement in %BMIp95. A 5-percentage point decrease in %BMIp95 was associated with improvement in cardiometabolic risk factors.

CONCLUSIONS

Overall, treatment in pediatric weight management programs is associated with a modest median decrease in BMI as measured by change in %BMIp95. Further studies are needed to confirm these findings, as well as to identify additional strategies to enhance the effectiveness of these multicomponent interventions for youth with severe obesity.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02121132.

The approach to an isolated close anterior margin in breast conserving surgery

INTRODUCTION

Although close radial margins after breast-conserving surgery routinely undergo re-excision, appropriate management of patients with close anterior margins remains a topic of controversy. An increasing body of literature suggests that re-excision of close anterior margins yields low rates of residual malignancy and may only be necessary in selected patients. The aim of this study was to examine the management of close anterior margins after breast conserving surgery in a single institution and to analyse the rate of residual disease in re-excised anterior margins.

METHODS

All patients having breast conserving surgery at St Vincent's University Hospital from January 2008 to December 2012 were reviewed retrospectively. Data collected included patient demographics, tumour characteristics, margin positivity, re-excision rates and definitive histology of the re-excision specimens. A close margin was defined as les than 2 mm.

RESULTS

A total of 930 patients were included with an average age of 65 years (range 29-94 years). Of these, 121 (13%) had a close anterior margin. Further re-excison of the anterior margin was carried out in 37 patients (30.6%) and a further 16 (13.2%) proceeded to mastectomy. Residual disease was found in 18.5% (7/36) of those who underwent re-excision and 7/16 (43.75%) of those who underwent mastectomy. Overall, 11.57% (14/121) of patients with close anterior margins were subsequently found to have residual disease.

CONCLUSION

The low yield of residual disease in re-excised anterior margins specimens supports the concept that routine re-excision of close anterior margins is not necessary. Further research is required to definitively assess its influence on the risk of local recurrence.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

57 Non-targeted metabolomic profiles within the uterine milieu of porcine pregnancies containing populations of uniform or diverse spherical, ovoid, or tubular conceptuses during initiation of embryo elongation

Alterations in the signalling of critical molecular factors within the uterine milieu result in deficiencies in embryo elongation, leading directly to embryonic loss as well as delayed elongation. The objective of this study was to identify metabolites within the uterine environment from populations of uniform and diverse porcine conceptuses as they transition between spherical, ovoid, and tubular conceptuses during the initiation of embryo elongation. White crossbred gilts (n=38) were bred at standing oestrus (designated Day 0) and again 24h later and randomly assigned to collection group. At Day 9, 10, or 11 of gestation, reproductive tracts were collected immediately following harvest and flushed with 40mL of RPMI-1640 media. Conceptus morphologies were assessed from each pregnancy to assign to 1 of 5 treatment groups based on these morphologies: (1) uniform spherical (n=8); (2) diverse spherical and ovoid (n=8); (3) uniform ovoid (n=8); (4) diverse ovoid and tubular (n=8); and (5) uniform tubular (n=6). Subsequently uterine flushings from these pregnancies were submitted for non-targeted profiling by gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) techniques. Raw spectral data were processed using the XCMS package in R (R Foundation for Statistical Computing, Vienna, Austria) and features were clustered using RAMclustR. Unsupervised multivariate principal component analysis was performed in R using pcamethods package, and univariate ANOVA was performed in R with a Benjamini-Hochberg false discovery rate adjustment. Principal component analysis of the GC-MS and UPLC-MS data identified 153 and 104 metabolites, respectively. Of the identified metabolites, 51 and 71 metabolites from the GC-MS and UPLC-MS analysis, respectively, corresponded to known compounds. After false discovery rate adjustment of the GC-MS and UPLC-MS data, 38 and 59 metabolites from the GC-MS and UPLC-MS analysis, respectively, differed (P&lt;0.05) in uterine flushings from pregnancies for the 5 conceptus stages. Some metabolites were greater (P&lt;0.05) in abundance for uterine flushings containing earlier stage conceptuses (i.e. spherical) such as uric acid, tryptophan, 5-hydroxy-L-tryptophan, and L-tryosine. In contrast, some metabolites were greater (P&lt;0.05) in abundance for uterine flushings containing later stage conceptuses (i.e. tubular) such as creatinine, serine, isovaleryl-I-carnitine, and lauric diethaolamide. These data illustrate several putative metabolites that change within the uterine milieu as porcine embryos transition between spherical, ovoid, and tubular conceptuses. Funding was provided by USDA-NIFA-AFRI Grant no. 2017-67015-26456.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω_{0}^{T}<5.58×10^{-8}, Ω_{0}^{V}<6.35×10^{-8}, and Ω_{0}^{S}<1.08×10^{-7} at a reference frequency f_{0}=25  Hz.

Introducing an E-learning Solution for Medical Education in Liberia

Background:

The Ebola virus epidemic and civil war in Liberia left the country in need of strengthening the health workforce. E-learning in medical education provides relevant learning opportunities for students, develops faculty competencies, and assists with the retention of healthcare workers. The Stellenbosch University Rural Medical Education Partnership Initiative (SURMEPI), the College of Health and Life Sciences (COHLS) at the University of Liberia (UL), and the Health Resources and Services Administration (HRSA) formed a partnership to create an e-learning solution for the COHLS.

Objective:

This article outlines the implementation of an e-learning solution for the COHLS in Monrovia, and describes the challenges met, the key successes achieved, and the lessons learnt.

Methods:

An initial scoping visit to Liberia was followed by three further on-site visits. Problems identified were: very limited or no network and computer resources, no internet connection, intermittent power, and lack of IT skills. We followed an evolutionary approach to infrastructure implementation by trying various solutions before settling on an offsite-hosted solution using Software as a Service (SaaS). Local staff were upskilled to administer this while remote support from Stellenbosch IT was provided. A stable internet connection was established. Staff and students can access the Learning Management System (LMS) 24/7 using mobile devices and laptops. Workshops were held where staff were taught how to produce online teaching material. Each class has at least one teaching assistant to assist lecturers with uploading and indexing material on the LMS.

A benchmarking visit by COHLS faculty to Stellenbosch University took place, during which an e-learning strategic plan was drawn up. Further online workshops were conducted, and teaching materials were placed on the new LMS.

Outcomes:

The intranet that was established consisted of internet connection and software as a service in the form of Office 365, providing access to several products and services. The e-learning model attended to technology and human resources simultaneously. The e-learning strategy aimed to improve teaching and learning at the COHLS, boost the number of qualified doctors, reduce the workload on lecturers, and be scalable in the future.

Conclusion:

It is challenging to implement e-learning in medical education. Inadequate infrastructure, limited bandwidth, lack of skilled IT staff, unreliable power supply, time commitment, and ongoing maintenance all need to be overcome. The creation of an e-learning solution for the COHLS over a period of 15 months was enabled by the common vision and close collaboration of the three partners. This model can potentially be replicated across other faculties in the University of Liberia and other educational institutions in Liberia.

GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25  Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25  Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.

The Implications of Cognitive Psychology for Computer-Assisted Instruction

An information processing model is used to describe the learning process. The implications of some of these cognitive concepts are examined in the context of computer-assisted instruction.

First Search for Nontensorial Gravitational Waves from Known Pulsars

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Effects of in situ exposure to tritiated natural environments: A multi-biomarker approach using the fathead minnow, Pimephales promelas

Aquatic ecosystems are chronically exposed to radionuclides as well as other pollutants. Increased concentrations of pollutants in aquatic environments can present a risk to exposed organisms, including fish. The goal of this study was to characterize the effects of tritium, in the context of natural environments, on the health of fathead minnow, Pimephales promelas. Fish were exposed to tritium (activity concentrations ranging from 2 to 23,000Bq/L) and also to various concentrations of several metals to replicate multiple-stressor environments. Fish were exposed for 60days, then transferred to the tritium background site where they stayed for another 60days. Tritium, in the forms of tritiated water (HTO) and organically bound tritium (OBT), and a series of fish health indicators were measured in fish tissues at seven time points throughout the 120days required to complete the exposure and the depuration phases. Results showed effects of environmental exposure following the increase of tritium activity and metals concentrations in water. The internal dose rates of tritium, estimated from tissue HTO and OBT activity concentrations, were consistently low (maximum of 0.2μGy/h) compared to levels at which population effects may be expected (>100μGy/h) and no effects were observed on survival, fish condition, gonado-somatic, hepato-somatic, spleno-somatic and metabolic indices (RNA/DNA, proteins/DNA and protein carbonylation (in gonads and kidneys)). Using multivariate analyses, we showed that several biomarkers (DNA damages, MN frequency, gamma-H2AX, SFA/MUFA ratios, lysosomal membrane integrity, AChE, SOD, phagocytosis and esterase activities) were exclusively correlated with fish tritium internal dose rate, showing that tritium induced genotoxicity, DNA repair activity, changes in fatty acid composition, and immune, neural and antioxidant responses. Some biomarkers were responding to the presence of metals, but overall, more biomarkers were linked to internalized tritium. The results are discussed in the context of multiple stressors involving metals and tritium.

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.