A new ground level neutron monitor for space weather assessment.

We report on a new ground-level neutron monitor design for studying cosmic rays and fluxes of solar energetic particles at the Earth's surface. The first-of-its-kind instrument, named the NM-2023 after the year it was standardised and following convention, will be installed at a United Kingdom Meteorological Office observatory (expected completion mid 2024) and will reintroduce such monitoring in the UK for the first time since ca. 1984. Monte Carlo radiation transport code is used for the development and application of parameterised models to investigate alternative neutron detectors, their location and bulk material geometry in a realistic cosmic ray neutron field. Benchmarked against a model of the current and most widespread design standardised in 1964 (the NM-64), two main parameterisation studies are conducted; a simplified standard model and a concept slab parameterisation. We show that the NM-64 standard is well optimised for the intended large-diameter boron trifluoride (BF 3 ) proportional counters but not for multiple smaller diameter counters. The new design (based on a novel slab arrangement) produces comparable counting efficiencies to an NM-64 with six BF 3 counters and has the added advantage of being more compact, lower cost and avoids the use of highly toxic BF 3 .

Vanquishing the computational cost of passive gamma emission tomography simulations leveraging physics-aware reduced order modeling.

Passive Gamma Emission Tomography (PGET) has been developed by the International Atomic Energy Agency to directly image the spatial distribution of individual fuel pins in a spent nuclear fuel assembly and determine potential diversion. The analysis and interpretation of PGET measurements rely on the availability of comprehensive datasets. Experimental data are expensive and limited, so Monte Carlo simulations are used to augment them. However, Monte Carlo simulations have a high computational cost to simulate the 360 angular views of the tomography. Similar challenges pervade numerical science. With the aim to create a large dataset of PGET simulated scenarios, we addressed the computational cost of Monte Carlo simulations by developing a physics-aware reduced order modeling approach. This approach combines a small subset of the 360 angular views (limited views approach) with a computationally inexpensive proxy solution (real-time forward model) that brings the essence of the physics to obtain a real-time high-fidelity solution at all angular views but at a fraction of the computational cost. The method's ability to reconstruct 360 views with accuracy from a limited set of angular views is demonstrated by testing its performance for different types of reactor fuel assemblies.

Characterization of 252Cf sources using high-resolution gamma spectroscopy.

Californium-252 is used as a neutron calibration source for passive neutron correlation counting. Source age and isotopic information are needed to make decay corrections to the neutron emission rate due to the influence of 250Cf. Gamma-ray signatures present in the spectrum from spontaneous fission products and odd-numbered Cf isotopes can be used with high accuracy to confirm or query declared values on a technical data sheet. This method is good practice for independently verifying the content of 252Cf calibration sources.

Association of Ankle Arthritis Score With Need for Revision Surgery.

BACKGROUND: The Ankle Arthritis Score (AAS) is a new patient-reported outcome derived from the Ankle Osteoarthritis Scale (AOS). This study analyzed longitudinally collected data from a cohort of patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) Ankle Arthritis Study in order to evaluate whether the postoperative AAS is associated with need for revision surgery. METHODS: A multicenter, prospective, ankle-reconstruction study enrolled 653 ankles undergoing total ankle replacement (TAR) or ankle arthrodesis (AA). The AAS was given at baseline and annually during postoperative follow-up. Time to revision surgery was modeled using a proportional hazards model. The final sample included 531 ankles in 509 patients. RESULTS: Sixty-two patients underwent metal-component revision and 8 underwent arthrodesis revision during the follow-up time period. The remaining 461 unrevised ankles (300 TAR, 161 AA) had a minimum follow-up of 2 years (average of 3.4 years). Revision surgery after TAR was found to be associated with a higher postoperative AAS and a longer follow-up. The hazard ratio for the AAS indicated that for every 1-point increase in the score, the rate of revision surgery after TAR was 1 percentage point higher. CONCLUSIONS: TAR patients who reported higher levels of postoperative functional impairment, as indicated by a higher AAS, were more likely to require metal-component revision surgery. After adjustment for other patient factors, the risk of revision surgery increased with length of follow-up after TAR. This study provides further evidence for the utility of the AAS in the clinical setting. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Radiographic evaluation of the ankle syndesmosis.

BACKGROUND: Radiographic measurements to document ankle anatomy have been suggested in recent literature to be inadequate. Focus has been put on stress views and computed tomography; however, there are also issues with these modalities. An orthogonal view that could be used both statically and dynamically could help determine syndesmotic stability. The purpose of this study was to determine a parameter on a normal lateral ankle radiograph that will increase the reliability of standard radiography in diagnosing syndesmotic integrity. METHODS: Three orthopedic surgeons reviewed 80 lateral ankle radiographs. Thirty of those radiographs were reviewed on a second occasion. Rotation of the radiographs was determined by evaluating the overlap of the talar dome. Four radiographic parameters were measured 1 cm above the tibial plafond: fibular width, tibial width, and anterior and posterior tibiofibular intervals. RESULTS: Seventy-two radiographs were determined by consensus to be adequate. Means and ratios were documented to determine the relationship of the fibula to the tibia. Interrater reliability ranged from moderate to near-perfect, and the intrarater reliability was documented for each ratio. The anterior tibiofibular ratio was shown to be strong to near-perfect. It demonstrates that 40% of the tibia should be seen anterior to the fibula at 1cm above the tibial plafond. CONCLUSION: The anterior tibiofibular ratio provides an orthogonal measure for the syndesmosis that, in conjunction with those parameters previously documented, could clinically and economically improve the diagnosis of syndesmotic disruptions.

CONTEXTE: Selon la littérature récente, les mesures radiographiques utilisées pour documenter l'anatomie de la cheville seraient inadéquates. L'accent a été placé sur les clichés de cheville en position de stress et sur la tomodensitométrie, mais ces modalités présentent également des inconvénients. Une vue orthogonale utilisée en position statique et en position dynamique pourrait aider à évaluer la stabilité syndesmotique. Le but de cette étude était de déterminer quel paramètre de la radiographie latérale normale de la cheville accroîtrait la fiabilité de la radiographie standard pour le diagnostic de l'intégrité syndesmotique. MÉTHODES: Trois chirurgiens orthopédistes ont passé en revue 80 radiographies latérales de la cheville. Trente de ces radiographies ont été interprétées une deuxième fois. La rotation des radiographies a été déterminée par l'évaluation du chevauchement du dôme talien. Quatre paramètres radiographiques ont été mesurés à 1 cm audessus du plafond tibial : la largeur du péroné, la largeur du tibia et les intervalles tibiofibulaires antérieur et postérieur. RÉSULTATS: Soixante-douze radiographies ont consensuellement été jugées adéquates. Les moyennes et les ratios ont été notés pour établir le rapport péroné-tibia. La fiabilité inter-examinateur a varié de modérée à quasi-parfaite et la fiabilité intra-examinateur a été documentée pour chaque ratio. Le ratio tibiofibulaire antérieur s'est révélé être un paramètre solide à quasi-parfait. Il démontre que 40 % du tibia devrait être visible à l'avant du péroné à 1 cm au-dessus du plafond tibial. CONCLUSION: Le ratio tibiofibulaire antérieur constitue une mesure orthogonale pour la syndesmose qui, en conjonction avec les paramètres précédemment documentés, permettrait d'améliorer le diagnostic des troubles syndesmotiques aux plans clinique et économique.

Therapy for naming difficulties in bilingual aphasia: which language benefits?

BACKGROUND: The majority of the world's population is bilingual. Yet, therapy studies involving bilingual people with aphasia are rare and have produced conflicting results. One recent study suggested that therapy can assist word retrieval in bilingual aphasia, with effects generalizing to related words in the untreated language. However, this cross-linguistic generalisation only occurred into the person's stronger language (L1). While indicative, these findings were derived from just three participants, and only one received therapy in both languages. AIMS: This study addressed the following questions. Do bilingual people with aphasia respond to naming therapy techniques developed for the monolingual population? Do languages respond differently to therapy and, if so, are gains influenced by language dominance? Does cross-linguistic generalisation occur and does this depend on the therapy approach? Is cross-linguistic generalisation more likely following treatment in L2 or L1? METHODS & PROCEDURES: The study involved five aphasic participants who were bilingual in English and Bengali. Testing showed that their severity and dominance patterns varied, so the study adopted a case series rather than a group design. Each person received two phases of naming therapy, one in Bengali and one in English. Each phase treated two groups of words with semantic and phonological tasks, respectively. The effects of therapy were measured with a picture-naming task involving both treated and untreated (control) items. This was administered in both languages on four occasions: two pre-therapy, one immediately post-therapy and one 4 weeks after therapy had ceased. Testing and therapy in Bengali was administered by bilingual co-workers. OUTCOMES & RESULTS: Four of the five participants made significant gains from at least one episode of therapy. Benefits arose in both languages and from both semantic and phonological tasks. There were three instances of cross-linguistic generalisation, which occurred when items had been treated in the person's dominant language using semantic tasks. CONCLUSIONS & IMPLICATIONS: This study suggests that 'typical' naming treatments can be effective for some bilingual people with aphasia, with both L1 and L2 benefiting. It offers evidence of cross-linguistic generalisation, and suggests that this is most likely to arise from semantic therapy approaches. In contrast to some results in the academic literature, the direction of generalisation was from LI to L2. The theoretical implications of these findings are considered. Finally, the results support the use of bilingual co-workers in therapy delivery.