Hierarchical Reinforcement Learning for Open-Domain Dialog

Open-domain dialog generation is a challenging problem; maximum likelihood training can lead to repetitive outputs, models have difficulty tracking long-term conversational goals, and training on standard movie or online datasets may lead to the generation of inappropriate, biased, or offensive text. Reinforcement Learning (RL) is a powerful framework that could potentially address these issues, for example by allowing a dialog model to optimize for reducing toxicity and repetitiveness. However, previous approaches which apply RL to open-domain dialog generation do so at the word level, making it difficult for the model to learn proper credit assignment for long-term conversational rewards. In this paper, we propose a novel approach to hierarchical reinforcement learning, VHRL, which uses policy gradients to tune the utterance-level embedding of a variational sequence model. This hierarchical approach provides greater flexibility for learning long-term, conversational rewards. We use self-play and RL to optimize for a set of human-centered conversation metrics, and show that our approach provides significant improvements -- in terms of both human evaluation and automatic metrics -- over state-of-the-art dialog models, including Transformers

Infectious disease surveillance for refugees at borders and in destination countries: a scoping review

Background Data on infectious disease surveillance for migrants on arrival and in destination countries are limited, despite global migration increases, and more are needed to inform national surveillance policies. Our study aimed to examine the scope of existing literature including existing infectious disease surveillance activities, surveillance methods used, surveillance policies or protocols, and potential lessons reported. Methods Using Arksey and O'Malley's six-stage approach, we screened four scientific databases systematically and 11 websites, Google, and Google Scholar purposively using search terms related to 'refugee' and 'infectious disease surveillance' with no restrictions on time-period or country. Title/abstracts and full texts were screened against eligibility criteria and extracted data were synthesised thematically. Results We included 20 eligible sources of 728 identified. Reporting countries were primarily European and all were published between 1999 and 2019. Surveillance methods included 9 sources on syndromic surveillance, 2 on Early Warning and Response (EWAR), 1 on cross-border surveillance, and 1 on GeoSentinel clinic surveillance. Only 7 sources mentioned existing surveillance protocols and communication with reporting sites, while policies around surveillance were almost non-existent. Eleven included achievements such as improved partner collaboration, while 6 reported the lack of systematic approaches to surveillance.ConclusionThis study identified minimal literature on infectious disease surveillance for migrants in transit and destination countries. We found significant gaps geographically and on surveillance policies and protocols. Countries receiving refugees could document and share disease surveillance methods and findings to fill these gaps and support other countries in improving disease surveillance

Assessing Practice and Criteria for Green Roof Maintenance on High-rise Residential Building in Malaysia

Urbanisation inevitably shows a positive sign in increasing the economic reputation of a country. Nevertheless, it has led to several problems including the deficit in green spaces and destruction of the natural environment, therefore green building is introduced as an alternative to overcome crucial environmental issues. Numerous approaches were also adopted to reduce other environmental issues such as urban heat island, air pollution and lack of green spaces. One of the sustainable approaches that help to minimise the environmental problems is by using the means of vegetation or plant material on rooftops or also known as the green roof. The implementation of the green roof on top of buildings is becoming a trend in the urban cities as it provides numerous benefits to the green development. The green roof is also part of criteria in green building and among the benefits, implementing green roofs will reduce heat flux, optimise energy efficiency and improve stormwater management. However, despite the benefits, enhancement on the green roof installation and maintenance consideration are two factors which are still largely unexplored as the main significant factor in the viability of the green roof installation. Hence, this paper is aimed to determine the vital criteria of maintenance and its ranking towards the establishment of best practice maintenance for the green roof, by focusing on high-rise residential. Questionnaires were distributed by email and through an online survey to 30 maintenance managers of green roof of high-rise residential in Kuala Lumpur and the samples are drawn by using purposive sampling technique. The results showed that the most significant maintenance criteria of the green roof are drainage, followed by waterproofing, irrigation, water retention, and roof slab. The outcome of this study has provided a significant contribution to the current maintenance practice of green roof by prioritising the criteria of maintenance and key address of green roof, where it may help to standardise the maintenance practice of the green roof in the tropical climate of Malaysia

Review of Significant Maintenance Criteria for Tropical Green Roofs in Malaysia

The implementation of green roofs on the top of buildings is becoming a trend in urban cities as they provide numerous benefits for green development growth. In Malaysia, numerous approaches towards sustainable development have been adopted in order to overcome crucial environmental issues such as urban heat islands, air pollution and lack of green spaces. One of the sustainable approaches that helps to minimize such problems is the use of vegetation or plant material on rooftops, also known as green roofs. Among the benefits of implementing green roofs or buildings are reducing heat flux, optimizing energy efficiency, and improving storm water management. Despite the benefits of green roof installation, the maintenance consideration is still largely unexplored and is a significant factor in the viability of green roof installation. Therefore, this paper aims to identify the significant criteria for green roof maintenance practice in Malaysia, as an added value to the existing practice that has previously been more concerned with design and benefit considerations. The literature findings reveal that there are generally 20 criteria related to such maintenance. Out of these, six are identified as the most significant factors in the best practice of green roof maintenance, being appropriate and important for the Malaysian tropical climate. The findings can serve as added value to existing practice, which has previously been more concerned with design and benefit. Therefore, they will also help to improve current green roof maintenance undertaken by building operators and maintenance managers

Stillbirths and quality of care during labour at the low resource referral hospital of Zanzibar: a case-control study

Background: To study determinants of stillbirths as indicators of quality of care during labour in an East African low resource referral hospital. Methods: A criterion-based unmatched unblinded case-control study of singleton stillbirths with birthweight ≥2000 g (n = 139), compared to controls with birthweight ≥2000 g and Apgar score ≥7 (n = 249). Results: The overall facility-based stillbirth rate was 59 per 1000 total births, of which 25 % was not reported in the hospital's registers. The majority of singletons had birthweight ≥2000 g (n = 139; 79 %), and foetal heart rate was present on admission in 72 (52 %) of these (intra-hospital stillbirths). Overall, poor quality of care during labour was the prevailing determinant of 71 (99 %) intra-hospital stillbirths, and median time from last foetal heart assessment till diagnosis of foetal death or delivery was 210 min. (interquartile range: 75-315 min.). Of intra-hospital stillbirths, 26 (36 %) received oxytocin augmentation (23 % among controls; odds ratio (OR) 1.86, 95 % confidential interval (CI) 1.06-3.27); 15 (58 %) on doubtful indication where either labour progress was normal or less dangerous interventions could have been effective, e.g. rupture of membranes. Substandard management of prolonged labour frequently led to unnecessary caesarean sections. The caesarean section rate among all stillbirths was 26 % (11 % among controls; OR 2.94, 95 % CI 1.68-5.14), and vacuum extraction was hardly ever done. Of women experiencing stillbirth, 27 (19 %) had severe hypertensive disorders (4 % among controls; OR 5.76, 95 % CI 2.70-12.31), but 18 (67 %) of these did not receive antihypertensives. An additional 33 (24 %) did not have blood pressure recorded during active labour. When compared to controls, stillbirths were characterized by longer admissions during labour. However, substandard care was prevalent in both cases and controls and caused potential risks for the entire population. Notably, women with foetal death on admission were in the biggest danger of neglect. Conclusions: Intrapartum management of women experiencing stillbirth was a simple yet strong indicator of quality of care. Substandard care led to perinatal as well as maternal risks, which furthermore were related to unnecessary complex, time consuming, and costly interventions. Improvement of obstetric care is warranted to end preventable birth-related deaths and disabilities. Trial registration: This is the baseline analysis of the PartoMa trial, which is registered on ClinicalTrials.org (NCT02318420, 4th November 2014)

Scaling up context-tailored clinical guidelines and training to improve childbirth care in urban, low-resource maternity units in Tanzania: A protocol for a stepped-wedged cluster randomized trial with embedded qualitative and economic analyses (The PartoMa Scale-Up Study)

While facility births are increasing in many low-resource settings, quality of care often does not follow suit; maternal and perinatal mortality and morbidity remain unacceptably high. Therefore, realistic, context-tailored clinical support is crucially needed to assist birth attendants in resource-constrained realities to provide best possible evidence-based and respectful care. Our pilot study in Zanzibar suggested that co-created clinical practice guidelines (CPGs) and low-dose, high-frequency training (PartoMa intervention) were associated with improved childbirth care and survival. We now aim to modify, implement, and evaluate this multi-faceted intervention in five high-volume, urban maternity units in Dar es Salaam, Tanzania (approximately 60,000 births annually). This PartoMa Scale-up Study will include four main steps: I. Mixed-methods situational analysis exploring factors affecting care; II. Co-created contextual modifications to the pilot CPGs and training, based on step I; III. Implementation and evaluation of the modified intervention; IV. Development of a framework for co-creation of context-specific CPGs and training, of relevance in comparable fields. The implementation and evaluation design is a theory-based, stepped-wedged cluster-randomised trial with embedded qualitative and economic assessments. Women in active labour and their offspring will be followed until discharge to assess provided and experienced care, intra-hospital perinatal deaths, Apgar scores, and caesarean sections that could potentially be avoided. Birth attendants\u27 perceptions, intervention use and possible associated learning will be analysed. Moreover, as further detailed in the accompanying article, a qualitative in-depth investigation will explore behavioural, biomedical, and structural elements that might interact with non-linear and multiplying effects to shape health providers\u27 clinical practices. Finally, the incremental cost-effectiveness of co-creating and implementing the PartoMa intervention is calculated. Such real-world scale-up of context-tailored CPGs and training within an existing health system may enable a comprehensive understanding of how impact is achieved or not, and how it may be translated between contexts and sustained.Trial registration number: NCT04685668

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe