Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

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.

Barriers to participation in randomised controlled trials: a systematic review

METHOD

A systematic review of three bibliographic databases from 1986 to 1996 identified 78 papers reporting barriers to recruitment of clinicians and patients to randomised controlled trials.

RESULTS

Clinician barriers included: time constraints, lack of staff and training, worry about the impact on the doctor-patient relationship, concern for patients, loss of professional autonomy, difficulty with the consent procedure, lack of rewards and recognition, and an insufficiently interesting question. Patient barriers included: additional demands of the trial, patient preferences, worry caused by uncertainty, and concerns about information and consent.

CONCLUSIONS

To overcome barriers to clinician recruitment, the trial should address an important research question and the protocol and data collection should be as straightforward as possible. The demands on clinicians and patients should be kept to a minimum. Dedicated research staff may be required to support clinical staff and patients. The recruitment aspects of a randomised controlled trial should be carefully planned and piloted. Further work is needed to quantify the extent of problems associated with clinician and patient participation, and proper evaluation is required of strategies to overcome barriers.

GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

The Dublin randomized controlled trial of intrapartum fetal heart rate monitoring

In a randomized controlled trial involving 12,964 women, a policy of continuous electronic intrapartum fetal heart monitoring was compared with an alternative policy of intermittent auscultation, both policies including an option to measure fetal scalp blood pH. Women allocated to electronic fetal heart monitoring had shorter labors and received less analgesia. The caesarean delivery rates were 2.4% for electronic fetal heart monitoring and 2.2% for intermittent auscultation but this small difference arose from the identification of nearly twice as many fetuses with low scalp pH (less than 7.20) in the electronic fetal heart monitoring group. The forceps delivery rate was 8.2% in the electronic fetal heart monitoring group compared with 6.3% in the intermittent auscultation group, and this excess was explained by more instrumental deliveries prompted by fetal heart rate abnormalities. There were 14 stillbirths and neonatal deaths in each group, with a similar distribution of causes. There were no apparent differences in the rates of low Apgar scores, need for resuscitation, or transfer to the special care nursery. Cases of neonatal seizures and persistent abnormal neurological signs followed by survival were twice as frequent in the intermittent auscultation group, and this differential effect was related to duration of labor. Follow-up at 1 year of babies who survived neonatal seizures revealed three clearly abnormal infants in each group. The implications of these findings for both theory and practice are discussed.

Randomised controlled trial of effect of fish-oil supplementation on pregnancy duration

The high birthweights and long duration of pregnancy in the Faroe Islands led us to suggest that a high intake of marine-fat-derived n-3 fatty acids might prolong pregnancy by shifting the balance of production of prostaglandins involved in parturition. We have compared the effects on pregnancy duration, birthweight, and birth length of a fish-oil supplement, a control olive-oil supplement, and no supplementation. 533 healthy Danish women in week 30 of pregnancy were randomly assigned in a ratio of 2/1/1 to fish oil (four 1 g Pikasol capsules [containing 2.7 g n-3 fatty acids] per day), olive oil (four 1 g capsules per day), or no supplement. The three groups differed in mean length of gestation (p = 0.006), which was highest in the fish-oil group and lowest in the olive-oil group; the result was similar when the analysis was restricted to women with an estimate of gestation length based on early ultrasound findings (443 women). Pregnancies in the fish-oil group were on average 4.0 (95% confidence interval 1.5-6.4) days longer than those in the olive-oil group; the difference in birthweight was 107 (1-214) g. The effect of supplementation on length of gestation was influenced by intake of fish and of fish oil: the difference between fish-oil and other groups was increased by a low fish intake at baseline. Fish-oil supplementation in the third trimester seems to prolong pregnancy without detrimental effects on the growth of the fetus or on the course of labour.

Recruitment to randomised trials: strategies for trial enrollment and participation study. The STEPS study

OBJECTIVES

To identify factors associated with good and poor recruitment to multicentre trials.

DATA SOURCES

Part A: database of trials started in or after 1994 and were due to end before 2003 held by the Medical Research Council and Health Technology Assessment Programmes. Part B: interviews with people playing a wide range of roles within four trials that their funders identified as 'exemplars'. Part C: a large multicentre trial (the CRASH trial) of treatment for head injury.

REVIEW METHODS

The study used a number of different perspectives ('multiple lenses'), and three components. Part A: an epidemiological review of a cohort of trials. Part B: case studies of trials that appeared to have particularly interesting lessons for recruitment. Part C: a single, in-depth case study to examine the feasibility of applying a business-orientated analytical framework as a reference model in future trials.

RESULTS

In the 114 trials found in Part A, less than one-third recruited their original target within the time originally specified, and around one-third had extensions. Factors observed more often in trials that recruited successfully were: having a dedicated trial manager, being a cancer or drug trial, and having interventions only available inside the trial. The most commonly reported strategies to improve recruitment were newsletters and mailshots, but it was not possible to assess whether they were causally linked to changes in recruitment. The analyses in Part B suggested that successful trials were those addressing clinically important questions at a timely point. The investigators were held in high esteem by the interviewees, and the trials were firmly grounded in existing clinical practices, so that the trial processes were not alien to clinical collaborators, and the results could be easily applicable to future practice. The interviewees considered that the needs of patients were well served by participation in the trials. Clinical collaborators particularly appreciated clear delineation of roles, which released them from much of the workload associated with trial participation. There was a strong feeling from interviewees that they were proud to be part of a successful team. This pride fed into further success. Good groundwork and excellent communications across many levels of complex trial structures were considered to be extremely important, including training components for learning about trial interventions and processes, and team building. All four trials had faced recruitment problems, and extra insights into the working of trials were afforded by strategies invoked to address them. The process of the case study in Part C was able to draw attention to a body of research and practice in a different discipline (academic business studies). It generated a reference model derived from a combination of business theory and work within CRASH. This enabled identification of weaker managerial components within CRASH, and initiatives to strengthen them. Although it is not clear, even within CRASH, whether the initiatives that follow from developing and applying the model will be effective in increasing recruitment or other aspects of the success of the trial, the reference model could provide a template, with potential for those managing other trials to use or adapt it, especially at foundation stages. The model derived from this project could also be used as a diagnostic tool if trials have difficulties and hence as a basis for deciding what type of remedial action to take. It may also be useful for auditing the progress of trials, such as during external review.

CONCLUSIONS

While not producing sufficiently definitive results to make strong recommendations, the work here suggests that future trials should consider the different needs at different phases in the life of trials, and place greater emphasis on 'conduct' (the process of actually doing trials). This implies learning lessons from successful trialists and trial managers, with better training for issues relating to trial conduct. The complexity of large trials means that unanticipated difficulties are highly likely at some time in every trial. Part B suggested that successful trials were those flexible and robust enough to adapt to unexpected issues. Arguably, the trialists should also expect agility from funders within a proactive approach to monitoring ongoing trials. Further research into different recruitment patterns (including 'failures') may help to clarify whether the patterns seen in the 'exemplar' trials differ or are similar. The reference model from Part C needs to be further considered in other similar and different trials to assess its robustness. These and other strategies aimed at increasing recruitment and making trials more successful need to be formally evaluated for their effectiveness in a range of trials.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.

West Berkshire perineal management trial

One thousand women were allocated at random to one of two perineal management policies, both intended to minimise trauma during spontaneous vaginal delivery. In one the aim was to restrict episiotomy to fetal indications; in the other the operation was to be used more liberally to prevent perineal tears. The resultant episiotomy rates were 10% and 51% respectively. An intact perineum was more common among those allocated to the restrictive policy. This group experienced more perineal and labial tears, however, and included four of the five cases of severe trauma. There were no significant differences between the two groups either in neonatal state or in maternal pain and urinary symptoms 10 days and three months post partum. Women allocated to the restrictive policy were more likely to have resumed sexual intercourse within a month after delivery. These findings provide little support either for liberal use of episiotomy or for claims that reduced use of the operation decreases postpartum morbidity.

Beta-mimetics in preterm labour: an overview of the randomized controlled trials

Controversy continues about the use of beta-mimetic drugs in preterm labour. One reason for this is that the adequately controlled trials of these drugs have all been small and have thus provided very imprecise estimates of their effects. We have therefore conducted a 'meta-analysis' using data relating to 890 women who participated in the 16 methodologically acceptable controlled trials of these agents in the treatment of preterm labour. This analysis demonstrates an unequivocal effect of beta-mimetic tocolytic administration in delaying delivery, and this is reflected in a reduction in the frequency of preterm birth and low birthweight. However, no beneficial effect of this treatment on perinatal mortality or severe neonatal respiratory disorders could be detected.

Randomized comparison of reduction and fixation, bipolar hemiarthroplasty, and total hip arthroplasty. Treatment of displaced intracapsular hip fractures in healthy older patients

BACKGROUND

Orthopaedic surgeons vary in their management of displaced intracapsular fractures of the hip in healthy older patients. The aim of this investigation was to determine the functional, clinical, and resource consequences of three different types of surgical treatment.

METHODS

The study was a multicenter randomized controlled trial. Reduction and fixation was compared with bipolar hemiarthroplasty with cement and total hip replacement with cement. Participating surgeons elected to randomize their patients to be treated with either one of the three types of procedures or with either fixation or bipolar hemiarthroplasty. Functional outcomes were measured with a hip-rating questionnaire and the EuroQol health status measure. Clinical outcomes included mortality and complications. The direct health service costs were compared. Participants were followed up for two years.

RESULTS

Two hundred and seven patients were randomized to be treated with one of the three operations, and ninety-one were randomized to be treated with either fixation or bipolar hemiarthroplasty. There were no differences in the mortality rates among the treatment groups. The rate of secondary surgery was highest in the fixation group (39% compared with 5% in the group treated with bipolar hemiarthroplasty and 9% in the group treated with total hip replacement). The fixation group had the worst hip-rating-questionnaire and EuroQol scores at four and twelve months. The total hip replacement group had significantly better functional outcome scores at twenty-four months than the other two groups. Although fixation was initially the least costly procedure, this short-term advantage was eroded by significantly higher costs for subsequent hip-related hospital admissions.

CONCLUSIONS

Arthroplasty is more clinically effective and cost-effective than reduction and fixation in healthy older patients with a displaced intracapsular fracture of the hip. The long-term results of total hip replacement may be better than those of bipolar hemiarthroplasty.

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5_{-3.0}^{+5.7}M_{⊙} and 25.3_{-4.2}^{+2.8}M_{⊙} (at the 90% credible level). The luminosity distance of the source is 540_{-210}^{+130}  Mpc, corresponding to a redshift of z=0.11_{-0.04}^{+0.03}. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from 1160   deg^{2} using only the two LIGO detectors to 60  deg^{2} using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

The clinical effectiveness and cost-effectiveness of screening for open angle glaucoma: a systematic review and economic evaluation

OBJECTIVES

To assess whether open angle glaucoma (OAG) screening meets the UK National Screening Committee criteria, to compare screening strategies with case finding, to estimate test parameters, to model estimates of cost and cost-effectiveness, and to identify areas for future research.

DATA SOURCES

Major electronic databases were searched up to December 2005.

REVIEW METHODS

Screening strategies were developed by wide consultation. Markov submodels were developed to represent screening strategies. Parameter estimates were determined by systematic reviews of epidemiology, economic evaluations of screening, and effectiveness (test accuracy, screening and treatment). Tailored highly sensitive electronic searches were undertaken.

RESULTS

Most potential screening tests reviewed had an estimated specificity of 85% or higher. No test was clearly most accurate, with only a few, heterogeneous studies for each test. No randomised controlled trials (RCTs) of screening were identified. Based on two treatment RCTs, early treatment reduces the risk of progression. Extrapolating from this, and assuming accelerated progression with advancing disease severity, without treatment the mean time to blindness in at least one eye was approximately 23 years, compared to 35 years with treatment. Prevalence would have to be about 3-4% in 40 year olds with a screening interval of 10 years to approach cost-effectiveness. It is predicted that screening might be cost-effective in a 50-year-old cohort at a prevalence of 4% with a 10-year screening interval. General population screening at any age, thus, appears not to be cost-effective. Selective screening of groups with higher prevalence (family history, black ethnicity) might be worthwhile, although this would only cover 6% of the population. Extension to include other at-risk cohorts (e.g. myopia and diabetes) would include 37% of the general population, but the prevalence is then too low for screening to be considered cost-effective. Screening using a test with initial automated classification followed by assessment by a specialised optometrist, for test positives, was more cost-effective than initial specialised optometric assessment. The cost-effectiveness of the screening programme was highly sensitive to the perspective on costs (NHS or societal). In the base-case model, the NHS costs of visual impairment were estimated as 669 pounds. If annual societal costs were 8800 pounds, then screening might be considered cost-effective for a 40-year-old cohort with 1% OAG prevalence assuming a willingness to pay of 30,000 pounds per quality-adjusted life-year. Of lesser importance were changes to estimates of attendance for sight tests, incidence of OAG, rate of progression and utility values for each stage of OAG severity. Cost-effectiveness was not particularly sensitive to the accuracy of screening tests within the ranges observed. However, a highly specific test is required to reduce large numbers of false-positive referrals. The findings that population screening is unlikely to be cost-effective are based on an economic model whose parameter estimates have considerable uncertainty. In particular, if rate of progression and/or costs of visual impairment are higher than estimated then screening could be cost-effective.

CONCLUSIONS

While population screening is not cost-effective, the targeted screening of high-risk groups may be. Procedures for identifying those at risk, for quality assuring the programme, as well as adequate service provision for those screened positive would all be needed. Glaucoma detection can be improved by increasing attendance for eye examination, and improving the performance of current testing by either refining practice or adding in a technology-based first assessment, the latter being the more cost-effective option. This has implications for any future organisational changes in community eye-care services. Further research should aim to develop and provide quality data to populate the economic model, by conducting a feasibility study of interventions to improve detection, by obtaining further data on costs of blindness, risk of progression and health outcomes, and by conducting an RCT of interventions to improve the uptake of glaucoma testing.

Elasticity analysis as an important tool in evolutionary and population ecology

Elasticity analysis estimates the proportional change in the population growth rate for a proportional change in a vital rate (i.e. survival, growth or reproduction). It can be used to pinpoint those parts of an organism's life history that should be the focus of management effort, or those that contribute most to fitness. Recent theoretical work has emphasized some limitations of the technique, has overcome other problems, and has shown that it is robust to some violations of its underlying assumptions. Thus, although care is needed, elasticity analysis is a simple first step in answering important questions in evolutionary and population ecology.

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.

Laparoscopic surgery for inguinal hernia repair: systematic review of effectiveness and economic evaluation

OBJECTIVES

To determine whether laparoscopic methods are more effective and cost-effective than open mesh methods of inguinal hernia repair, and then whether laparoscopic transabdominal preperitoneal (TAPP) repair is more effective and cost-effective than laparoscopic totally extraperitoneal (TEP).

DATA SOURCES

Electronic databases. Conference proceedings. Manufacturers' submissions to the National Institute for Clinical Excellence (NICE) were reviewed.

REVIEW METHODS

Selected studies were rigorously assessed. Dichotomous outcome data were combined using the relative risk method and continuous outcomes were combined using the Mantel-Haenszel weighted mean difference method. Time to return to usual activities was described using hazard ratios derived from individual patient data reanalysis. A review of economic evaluations undertaken by NICE in 2001 was updated and an economic evaluation was performed. The estimation of cost-effectiveness focused on the comparison of laparoscopic repair with open flat mesh. A Markov model incorporating the data from the systematic review was used to estimate cost-effectiveness for a time horizon up to 25 years.

RESULTS

Thirty-seven randomised control trials (RCTs) and quasi-RCTs met the inclusion criteria on effectiveness. Fourteen studies were included in the review of economic evaluations. Laparoscopic repair was associated with a faster return to usual activities and less persisting pain and numbness. There also appeared to be fewer cases of wound/superficial infection and haematoma. However, operation times are longer and there appears to be a higher rate of serious complications in respect of visceral (especially bladder) injuries. Mesh infection is very uncommon with similar rates noted between the surgical approaches. There is no apparent difference in the rate of hernia recurrence. Laparoscopic repair was more costly to the health service than open repair, with an estimated extra cost from studies conducted in the UK of about 300-350 pounds per patient. The point estimates of cost provided by the economic model also suggest that the laparoscopic techniques are more costly (approximately 100-200 pounds more per patient after 5 years). From the review of economic evaluations, the estimates of incremental cost per additional day at usual activities were between 86 pounds and 130 pounds. Where productivity costs were included, they eliminated the cost differential between laparoscopic and open repair. Additional analysis incorporating new trial evidence suggested that TEP was associated with significantly more recurrences than open mesh but these data did not greatly influence cost-effectiveness.

CONCLUSIONS

For the management of unilateral hernias, the base-case analysis and most of the sensitivity analysis suggest that open flat mesh is the least costly option but provides less quality adjusted life years (QALYs) than TEP or TAPP. TEP is likely to dominate TAPP (on average TEP is estimated to be less costly and more effective). It is likely that, for management of symptomatic bilateral hernias, laparoscopic repair would be more cost-effective as differences in operation time (a key cost driver) may be reduced and differences in convalescence time are more marked (hence QALYs will increase) for laparoscopic compared with open mesh repair. When possible repair of contralateral occult hernias is taken into account, TEP repair is most likely to be considered cost-effective at threshold values for the cost per additional QALY above 20,000 pounds. The increased adoption of laparoscopic techniques may allow patients to return to usual activities faster. This may, for some people, reduce any loss of income. For the NHS, increased use of laparoscopic repair would lead to an increased requirement for training and the risk of serious complications may be higher. Chronic pain should now be addressed prospectively using standard definitions and allowing assessment of the degree of pain. More evidence is required on the loss of utility caused by persisting pain and numbness, as well as serious complications resulting from minor surgery. Prospective population-based registries of new surgical procedures may be the best way to address this, as a complement to randomised trials assessing effectiveness. Further research relating to whether the balance of advantages and disadvantages changes when hernias are recurrent or bilateral is also required as current data are limited. Methodologically sound RCTs are needed to consider the relative merits and risks of TAPP and TEP. Further methodological research is required into the complexity of laparoscopic groin hernia repair and the improvement of performance that accompanies experience.

Tests of General Relativity with GW150914

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13}  km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.

A randomized controlled trial of cervical cerclage in women at high risk of spontaneous preterm delivery

The effect of cervical suture on pregnancy outcome was studied in 194 women with a high risk (approximately 30%) of having a late abortion or a preterm delivery. The women were randomly allocated either to have a cervical suture inserted (n = 96) or to be managed without a suture (n = 98). There was no evidence that cervical cerclage either prolonged gestation or improved survival. Patients allocated to receive cerclage spent significantly longer in hospital, even when the period of admission for insertion was excluded. The patients in the cerclage group were more likely to receive tocolytic drugs, and more of them experienced puerperal pyrexia, although these differences between the groups were not statistically significant.

Social support and pregnancy outcome

A total of 509 women with a history of a low-birthweight (LBW, less than 2500 g) baby were recruited from the antenatal booking clinics of four hospitals and randomized to receive either a social support intervention in pregnancy in addition to standard antenatal care (the intervention group) or standard antenatal care only (the control group). At recruitment to the study, mean gestational age was 6 weeks, mean maternal age was 28.0 years, 86% of the women had one previous LBW baby, 11% had two and 2% had had three or more. The study population was socially disadvantaged: 77% of the women were working class, 18% had unemployed partners and 41% were smoking at booking. Social support was given by four research midwives in the form of 24-h contact telephone numbers and a programme of home visits, during which the midwives provided a listening service for the women to discuss any topic of concern to them, gave practical information and advice when asked, carried out referrals to other health professionals and welfare agencies as appropriate, and collected social and medical information. Pregnancy outcomes were assessed using obstetric case-note data (obtained for 507 women) and a postal questionnaire sent to all mothers 6 weeks after delivery (94% replied). Babies of intervention group mothers had a mean birthweight 38 g higher than that of control group babies; there were fewer very low-birthweight babies in the intervention group.(ABSTRACT TRUNCATED AT 250 WORDS)

Odorant response of individual sensilla on the Drosophila antenna

We have documented odor responses of all morphological classes of sensilla on the surface of the Drosophila antenna: sensilla basiconica, sensilla trichodea, and sensilla coeloconica. Both subtypes of s. basiconica, large and small, respond to odors. S. trichodea fall into different functional types. Type 1 appears narrowly tuned, as it responded only to cis-vaccenyl acetate, believed to be a pheromone. Type 2 responded to trans-2-hexenal and 4-methyl cyclohexanol. These two types of s. trichodea are differentially distributed on the antennal surface, and have dramatically different frequencies of spontaneous action potentials. Likewise, there are multiple types of s. coeloconica. One type if broadly tuned, responding most strongly to a test stimulus of butyric acid, but also to a variety of other odors; it is restricted to the dorso-medial portion of the third antennal segment. A second type gave detectable responses only to trans-2-hexenal. These results demonstrate that all classes of sensilla are olfactory, and they reveal the organizational complexity of the Drosophila olfactory system.

West Berkshire perineal management trial: three year follow up

Women who had participated in a randomised controlled trial of policies of restricted (10%) versus liberal (51%) episiotomy during spontaneous vaginal delivery were recontacted by postal questionnaire three years after delivery. Altogether 674 out of 1000 responded, and there was no evidence of a differential response rate between the two trial groups. Similar numbers of women in the two groups reported further deliveries, almost all of which had been vaginal and spontaneous. Fewer women allocated to restrictive use of episiotomy required perineal suturing after subsequent delivery, but this difference was not significant. Pain during sexual intercourse and incontinence of urine were equally reported in the two groups. The similarity in incontinence rates persisted when severity, type of incontinence, and subsequent deliveries were taken into account. Liberal use of episiotomy does not seem to prevent urinary incontinence or increase long term dyspareunia.

Routine formal fetal movement counting and risk of antepartum late death in normally formed singletons

The routine recommendation to women to count fetal movements daily during late pregnancy for the prevention of antepartum late fetal death in normally formed singletons has been evaluated. 68,000 women were randomly allocated within thirty-three pairs of clusters either to a policy of routine counting or to standard care, which might involve selective use of formal counting or informal noting of movements. Antepartum death rates for normally formed singletons were similar in the two groups, regardless of cause of prior risk status. Despite the counting policy, most of these fetuses were dead by the time the mothers received medical attention. The study does not rule out a beneficial effect, but at best, the policy would have to be used by about 1250 women to prevent 1 unexplained antepartum late fetal death, and an adverse effect is just as likely. In addition, formal routine counting would use considerable extra resources.

Exo84p is an exocyst protein essential for secretion

The exocyst is a multiprotein complex that plays an important role in secretory vesicle targeting and docking at the plasma membrane. Here we report the identification and characterization of a new component of the exocyst, Exo84p, in the yeast Saccharomyces cerevisiae. Yeast cells depleted of Exo84p cannot survive. These cells are defective in invertase secretion and accumulate vesicles similar to those in the late sec mutants. Exo84p co-immunoprecipitates with the exocyst components, and a portion of the Exo84p co-sediments with the exocyst complex in velocity gradients. The assembly of Exo84p into the exocyst complex requires two other subunits, Sec5p and Sec10p. Exo84p interacts with both Sec5p and Sec10p in a two-hybrid assay. Overexpression of Exo84p selectively suppresses the temperature sensitivity of a sec5 mutant. Exo84p specifically localizes to the bud tip or mother/daughter connection, sites of polarized secretion in the yeast S. cerevisiae. Exo84p is mislocalized in a sec5 mutant. These studies suggest that Exo84p is an essential protein that plays an important role in polarized secretion.

Prevalence of dust mites in the homes of people with asthma living in eight different geographic areas of the United States

The density and species prevalence of dust mites were determined at various times over a 5-year-period in 252 homes of dust mite sensitive people with asthma who lived in eight geographic areas of the United States (Cincinnati, Ohio; New Orleans, La.; Memphis, Tenn.; Galveston, Texas; Greenville, N.C.; Delray Beach, Fla.; San Diego and Los Angeles, Calif.). The most common dust mites found in the homes were Dermatophagoides farinae (DF), D. pteronyssinus (DP), Euroglyphus maynei (EM), and Blomia tropicalis. All homes in all locations contained Dermatophagoides spp. mites, but few homes were populated exclusively by either DF or DP alone. Most homes (81.7%) were coinhabitated by both DF and DP. In coinhabited homes one species was predominant and usually made up at least 75% of the total mite population. Prevalence of the dominant or only species present varied between homes within a geographic area. EM occurred in significant numbers in 35.7% of homes in New Orleans, Memphis, Galveston, Delray Beach, and San Diego. Blomia tropicalis occurred in these same cities but in low densities. For all dust samples, only 13 homes of the 252 sampled had 100 or fewer mites/gm dust, which is considered to be the threshold for sensitivity. Most homes had average mite densities of 500 or more mites/gm dust. The results of the present study suggest a significant and widespread occurrence of both DF and DP. Therefore extracts of both mite species should be considered for diagnostic tests and immunotherapy. Significant levels of EM were present in some areas. Thus sensitivity to EM should be considered in these areas.