Constraining Dark Matter Models with a Light Mediator at the PandaX-II Experiment.

We search for nuclear recoil signals of dark matter models with a light mediator in PandaX-II, a direct detection experiment in the China Jinping underground laboratory. Using data collected in 2016 and 2017 runs, corresponding to a total exposure of 54 ton day, we set upper limits on the zero-momentum dark matter-nucleon cross section. These limits have a strong dependence on the mediator mass when it is comparable to or below the typical momentum transfer. We apply our results to constrain self-interacting dark matter models with a light mediator mixing with standard model particles, and set strong limits on the model parameter space for the dark matter mass ranging from 5 GeV to 10 TeV.

Spin-Dependent Weakly-Interacting-Massive-Particle-Nucleon Cross Section Limits from First Data of PandaX-II Experiment.

New constraints are presented on the spin-dependent weakly-interacting-massive-particle–- (WIMP-)nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10^{4} kg day. Assuming a standard axial-vector spin-dependent WIMP interaction with ^{129}Xe and ^{131}Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c^{2} are set in all dark matter direct detection experiments. The minimum upper limit of 4.1×10^{-41} cm^{2} at 90% confidence level is obtained for a WIMP mass of 40 GeV/c^{2}. This represents more than a factor of 2 improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

Limits on Axion Couplings from the First 80 Days of Data of the PandaX-II Experiment.

We report new searches for solar axions and galactic axionlike dark matter particles, using the first low-background data from the PandaX-II experiment at China Jinping Underground Laboratory, corresponding to a total exposure of about 2.7×10^{4} kg day. No solar axion or galactic axionlike dark matter particle candidate has been identified. The upper limit on the axion-electron coupling (g_{Ae}) from the solar flux is found to be about 4.35×10^{-12} in the mass range from 10^{-5} to 1 keV/c^{2} with 90% confidence level, similar to the recent LUX result. We also report a new best limit from the ^{57}Fe deexcitation. On the other hand, the upper limit from the galactic axions is on the order of 10^{-13} in the mass range from 1 to 10 keV/c^{2} with 90% confidence level, slightly improved compared with the LUX.

Dark Matter Results from 54-Ton-Day Exposure of PandaX-II Experiment.

We report a new search for weakly interacting massive particles (WIMPs) using the combined low background data sets acquired in 2016 and 2017 from the PandaX-II experiment in China. The latest data set contains a new exposure of 77.1 live days, with the background reduced to a level of 0.8×10^{-3} evt/kg/day, improved by a factor of 2.5 in comparison to the previous run in 2016. No excess events are found above the expected background. With a total exposure of 5.4×10^{4} kg day, the most stringent upper limit on the spin-independent WIMP-nucleon cross section is set for a WIMP with mass larger than 100 GeV/c^{2}, with the lowest 90% C.L. exclusion at 8.6×10^{-47} cm^{2} at 40 GeV/c^{2}.

Dark Matter Results from First 98.7 Days of Data from the PandaX-II Experiment.

We report the weakly interacting massive particle (WIMP) dark matter search results using the first physics-run data of the PandaX-II 500 kg liquid xenon dual-phase time-projection chamber, operating at the China JinPing underground laboratory. No dark matter candidate is identified above background. In combination with the data set during the commissioning run, with a total exposure of 3.3×10^{4} kg day, the most stringent limit to the spin-independent interaction between the ordinary and WIMP dark matter is set for a range of dark matter mass between 5 and 1000 GeV/c^{2}. The best upper limit on the scattering cross section is found 2.5×10^{-46} cm^{2} for the WIMP mass 40 GeV/c^{2} at 90% confidence level.

Added value of assessing medical students' reflective writings in communication skills training: a longitudinal study in four academic centres.

OBJECTIVES: This study describes the development and implementation of a model to assess students' communication skills highlighting the use of reflective writing. We aimed to evaluate the usefulness of the students' reflections in the assessment of communication skills. DESIGN: Third-year and fourth-year medical students enrolled in an elective course on clinical communication skills development were assessed using different assessment methods. SETTING AND PARTICIPANTS: The communication skills course was offered at four universities (three in Brazil and one in Portugal) and included 69 students. OUTCOME MEASURES: The students were assessed by a Multiple-Choice Questionnaire (MCQ), an objective structured clinical examination (OSCE) and reflective writing narratives. The Cronbach's alpha, dimensionality and the person's correlation were applied to evaluate the reliability of the assessment methods and their correlations. Reflective witting was assessed by applying the Reflection Evaluation for Enhanced Competencies Tool Rubric (Reflect Score (RS)) to measure reflections' depth, and the Thematic Score (TS) to map and grade reflections' themes. RESULTS: The Cronbach alpha for the MCQ, OSCE global score, TS and RS were, respectively, 0.697, 0.633, 0.784 and 0.850. The interobserver correlation for the TS and RS were, respectively, 0.907 and 0.816. The assessment of reflection using the TS was significantly correlated with the MCQ (r=0.412; p=0.019), OSCE (0.439; p=0.012) and RS (0.410; p=0.020). The RS did not correlate with the MCQ and OSCE. CONCLUSIONS: Assessing reflection through mapping the themes and analysing the depth of reflective writing expands the assessment of communication skills. While the assessment of reflective themes is related to the cognitive and behavioural domains of learning, the reflective depth seems to be a specific competence, not correlated with other assessment methods-possibly a metacognitive domain.

Use of portfolios in teaching communication skills and professionalism for Portuguese-speaking medical students.

OBJECTIVES: This study aimed to analyse the effect of a portfolio with three activities fostering students' reflection, self-efficacy and teaching of communication skills and professionalism. METHODS: A cross-sectional study was applied with a sample of third- and fourth-year medical students in one Portuguese and three Brazilian universities. A three-activity portfolio (course evaluation and learning, self-efficacy activity and free reflective writing) was used during a two-month course on communication skills and professionalism. The 69 students enrolled in the course were invited to complete the three-activity portfolio via Likert-type questionnaires, open-ended questions and narrative. Content and lexical analysis and the Reflection Evaluation for Learners' Enhanced Competencies Tool (REFLECT) were used for assessing the qualitative data. The questionnaires were evaluated using principal components analysis and Cronbach's α. Pearson's correlation was applied to portfolio activities. RESULTS: Of the 69 participants, 85.5% completed at least one activity. Reflecting on what they learned in the communication module, the students did not mention professionalism themes. In the self-efficacy activity on communication, 25% of the fragments were related to professionalism themes. There was a negative correlation between students' self-efficacy and the REFLECT rubric score (r(19)=-0.744; p< 0.0001). CONCLUSIONS: Teachers must consider the activity's influence on the reflections when assessing the portfolio. This model of a three-activity portfolio provided diverse ways of encouraging and assessing reflections, supporting teaching improvement and adaptation, evaluating students' self-efficacy and showing that students' higher reflective capacity may promote feelings of low effectiveness.