654 research outputs found

    Probing top-philic sgluons with LHC Run I data

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    Many theories beyond the Standard Model predict the existence of colored scalar states, known as sgluons, lying in the adjoint representation of the QCD gauge group. In scenarios where they are top-philic, sgluons are expected to be copiously pair-produced at the LHC via strong interactions with decays into pairs of top quarks or gluons. Consequently, sgluons can be sought in multijet and multitop events at the LHC. We revisit two LHC Run I analyses in which events featuring either the same-sign dileptonic decay of a four-top-quark system or its single leptonic decay are probed. Adopting a simplified model approach, we show how this reinterpretation allows us to extract simultaneous bounds on the sgluon mass and couplings.Comment: 6 pages, 2 figures; v2: some issues in Sec.3.1 clarified, version to appear in PL

    The efficacy of lenvatinib plus everolimus in patients with metastatic renal cell carcinoma exhibiting primary resistance to front-line targeted therapy or immunotherapy

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    BACKGROUND: Patients with primary refractory metastatic renal cell carcinoma (mRCC) have a dismal prognosis and poor response to subsequent treatments. While there are several approved second-line therapies, it remains critical to choose the most effective treatment regimen. PATIENTS AND METHODS: We identified 7 patients with clear cell mRCC who had primary resistance to vascular endothelial growth factor (VEGF)-targeted tyrosine kinase inhibitors (TKIs) or immune checkpoint inhibitor (ICI) combination therapy. The patients were treated with lenvatinib (a multitargeted TKI) plus everolimus (a mammalian target of rapamycin inhibitor). Among these 7 patients, 2 had prior TKI therapy, 3 had prior ICI therapy, and 2 had prior TKI and ICI therapy. We collected the patients\u27 clinical characteristics, molecular profiles, treatment durations, and toxicity outcomes. RESULTS: The median time to progression on prior therapies was 1.5 months. Lenvatinib plus everolimus was used either as a second-line (n = 4) or third-line (n = 3) therapy. As best responses, 3 patients had partial responses and 3 achieved stable disease. Patients were followed for ≥17 months; progression-free survival ranged from 3 to 15 months, and overall survival ranged from 4 to 17 months. CONCLUSION: These 7 cases provide real-world data for the use of lenvatinib plus everolimus in patients with mRCC with primary resistance to first-line VEGF-targeted TKIs or ICI combination therapy

    A Novel Approach to Contamination Suppression in Transmission Detectors for Radiotherapy

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    The current trend in X-ray radiotherapy is to treat cancers that are in difficult locations in the body using beams with a complex intensity profile. Intensity Modulated Radiotherapy (IMRT) is a treatment which improves the dose distribution to the tumour whilst reducing the dose to healthy tissue. Such treatments administer a larger dose per treatment fraction and hence require more complex methods to verify the accuracy of the treatment delivery. Measuring beam intensity fluctuations is difficult as the beam is heavily distorted after leaving thepatient and transmission detectors will attenuate the beam and change the energy spectrum of the beam. Monolithic Active Pixel Sensors (MAPS) are ideal solid-state detectors to measure the 2D beam profile of a radiotherapy beam upstream of the patient. MAPS sensors can be made very thin (∼ 30 μm) with still very good signal-to-noise performance. This means that the beam would pass through the sensor virtually undisturbed(< 1% attenuation). Pixel pitches of between 2 μm to 100 μm are commercially available. Large area devices (∼ 15 × 15 cm 2 ) have been produced. MAPS can be made radiation hard enough to befully functional after a large number of fractions. All this makes MAPS a very realistic transmission detector candidate for beam monitoring upstream of the patient. A remaining challenge for thin, upstream sensors is that the detectors are sensitive to the signal of both therapeutic photons and electron contamination. Here a method is presented to distinguish between the signal due to electrons and photons and thus provide real-time dosimetric information in very thin sensors that does not require Monte Carlo simulation of each linear accelerator treatment head

    Toward Pulse by Pulse Dosimetry Using an SC CVD Diamond Detector

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    Solid state detectors with nanosecond response timesto incoming radiation are increasingly present at the forefrontof radiotherapy dosimetry research. The fast response time ofmaterials, such as diamond, allow pulse by pulse dosimetry. Thereis a trend in radiotherapy to move towards shorter treatments,using fewer but more intense pulses with varying pulse rates andintensities. This makes the possibility of measuring individualpulses very attractive and would allow intervention during thetreatment and not just afterwards. Here an analogue front endhas been developed and combined with a CVD diamond detectorto provide real time, pulse by pulse beam intensity measure-ments.The front end design is discussed and the experimentalresults obtained using a medical LINAC are presented. Theresults show that pulse by pulse The device is capable of pulseby pulse beam intensity measurements up to pulse rates wellabove 1 kHz. The system performs so well that its variations arenegligible compared to the pulse to pulse intensity variations.The dosimetric performance of our system was compared toa commercially available, integrating diamond detector, themicroDiamond by PTW. The dose and dose-rate linearity of oursystem is comparable with the one of the microDiamond and hasthe additional advantage of being able to measure the depositeddose per pulse

    Dietetics students’ construction of competence through assessment and placement experiences

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    Aim Competency standards are widely adopted as a framework to describe standards of performance required in the workplace. Little is known, however, about how students construct competence. This qualitative study aimed to explore how dietetics students ready to graduate construct the concept of competence and the role of assessment in developing professional competence. Methods A qualitative description was used to gather data from a convenience sample of students ready to graduate from universities with accredited dietetics programs across Australia (10 out of 15 at the time of the study). A total of 11 focus groups were conducted to explore perspectives of competence and experiences of ‘competency-based’ assessment. Data were audio-recorded, transcribed and analysed using a thematic analysis approach. Results A total of 81 (n = 81) participants across 10 universities representing 22% of total students participated in the focus groups. Themes revealed that: (i) there is no shared understanding of competence; (ii) current work placement experiences may not reflect current standards or workforce needs; (iii) assessment approaches may not fully support the development of competence; and (iv) the competent performance of supervising dietitians/clinical educators in the workplace influences the construction of competence. Conclusions There is a need to work towards a shared understanding of dietetic entry-level competence in the profession. ‘Work-based’ learning experiences may need to be modified to ensure students meet current competency standards. Practitioners involved in student supervision need to acknowledge the influential role they have in the development of the future workforce

    Distress in working on dementia wards - a threat to compassionate care: a grounded theory study

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    Objectives - Nurses and health care workers are under increasing scrutiny from the general public and other professionals over their capacity for compassion. For example, in the UK, recruitment of nurses includes assessment of compassion through ?Values Based Recruitment?. However, compassionate care can be hindered when working in very challenging and pressurised environments. The study aimed to explore the experiences of managing work pressures in front-line NHS staff caring for older adults with dementia. One aspect of the analysis was to explore the factors that facilitate or hinder self-compassion and mindfulness, since these ways of responding to extreme pressure are likely to facilitate compassion towards others. Method- Ten front-line staff (a mixture of nurses and Health Care Assistants) from three inpatient dementia wards took part in qualitative interviews which were then analysed using constructivist grounded theory methods. Results - A theoretical framework was generated which highlighted the role of structural and interpersonal types of work pressure on individual responses and ways of managing pressure. A range of helpful and unhelpful strategies were employed and although many participants appreciated the importance of taking time to process and reflect on difficult emotions and experiences during work, there were significant structural and personal barriers to practicing mindfulness and self-compassion more fully. A sense of professionalism along with various organisational factors meant that much processing of difficult emotions had to take place largely out of work hours. Conclusions - Recruiting staff with high levels of compassion and training compassion to existing staff are not likely to significantly improve compassionate care alone in the context of extremely challenging work environments. Rather, organisational changes need to be made to model and reward self-compassion; staff training should focus on self-compassion and mindfulness, without which compassion to others is hindered. Strong professional values which may instil in care staff a belief in not displaying emotions at work should be considered carefully by professional bodies in order to provide guidance from pre-qualification onwards about how to balance professional conduct with appropriate expression of emotion in response to extreme situations
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