Comment on ''Near-threshold behavior of electron-impact excitation of He+(2s) and He+(2p)''

International audienceXu and Shakeshaft [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.84.024701 84, 024701 (2011)] presented theoretical cross sections for excitation of the 2s and 2p states of He+ at low collision energies, pointing out in particular the presence of cusps at the excitation threshold. We update their discussion of the comparison between theory and experiment, and confirm that results obtained using standard R-matrix and two-dimensional R-matrix propagation techniques also show such cusps

Simultaneous electron-photon excitation of helium in an Nd:YAG laser field

International audienceR-matrix Floquet theory is used to study the laser-assisted electron-impact excitation of helium at collision energies close to the He(1s2 ) thresholds in the presence of a Nd:YAG laser field of intensity 1010 W cm−2. A strong ac Stark mixing occurs between the 1s2s 3S and 1s2p 3Po states. The He−(1s2s2 2S) resonance gives rise to a series of structures in the integrated cross sections, in particular a dominant peak below the first excitation threshold. Agreement with experiment is very good at low energies, but at higher energies, the calculated signal remains small while the experimental results are very negative. The role of multiphoton ionization of the metastable states by the Nd:YAG laser field as a mechanism for signal loss in the experiment is also investigated

Simultaneous electronphoton excitation of helium in a CO2 laser field

International audienceThe R-matrix Floquet method is used to study electron-impact excitation of helium in the presence of a CO 2 laser field, for collision energies between 19 and 21.5 eV and laser intensities of 10 7 and 10 8 W cm −2. Collision geometries with the electron incident at various angles to the laser polarization axis are considered. The signal for production of metastable states is in good agreement with the results of a low-frequency approximation and a semi-classical approach, while agreement with experiment is reasonable

Marshall University Music Department Presents the Annual Cello Day, Ms. Lauren Dunseath, Clinician & Soloist

https://mds.marshall.edu/music_perf/1655/thumbnail.jp

Experimental and theoretical study of free-free electron-helium scattering in a CO2 laser field

International audienceFree-free transitions during the scattering of electrons by helium in the presence of a linearly polarized CO2 laser field are investigated both experimentally and theoretically. Signals for laser-assisted scattering at 22 eV with absorption or emission of up to two photons are measured at scattering angles between 20° and 70°, and are compared to the values obtained from an 11-state R-matrix Floquet calculation and from the low-frequency approximation of Kroll and Watson. The two sets of theoretical results are found to be in very good agreement for the scattering geometries considered in the experiment. The order of magnitude of the experimental results is reproduced by calculations with intensities in the region of 107 W cm-2. Agreement is improved by averaging the theoretical results over the spatial distributions of the three beams as well as the temporal intensity profile of the laser pulse, and by allowing for some misalignment of the three beams in the experiment

An Experiment in Synchronicity

AbstractClick here and insert your abstract text. Possible states theory generalizes about the process of change within a finite and discrete model of the universe. The possible states consist of all interactions between objects, including past, future and possible interactions. The theory posits a non-electromagnetic model of change in which change propagates without reference to space-time. The theory delivers verifiable predictions and is generally consistent with quantum theory. It offers the prospect of nonlocal connections between objects and change that is not constrained by conservation laws. The value of the concept as a basis for technology development depends upon the ability to manipulate the possible states, specifically to produce coherence in selected collections of states. An experiment is devised in which a coherent state path is created between the experimental components and loaded through interaction with non-coherent states. Discharge of coherence results in a burst of synchronistic events compatible with theoretical expectations. The experiment validates a specific control strategy and yields a large timewise anomaly. The results shed light on a potential sentient intelligence and upon the development of coherence in the possible states and enable a major advance in the control of change

Brief lifestyle interventions for prediabetes in primary care: a service evaluation

BackgroundThe increasing number of cases of prediabetes in the UK is concerning, particularly in Wales where there is no standard programme of support. The aim of the current service evaluation was to examine the effectiveness of brief lifestyle interventions on glucose tolerance in people at risk of developing type 2 diabetes.MethodsIn this pragmatic service evaluation clinical data on people deemed at risk of developing type 2 diabetes were evaluated from two GP clusters. Patients (n = 1207) received a single 15 to 30-min, face-to-face, consultation with a health care practitioner. Interventions were assessed by changes in HbA1c and distribution across the HbA1c ranges 12 months following intervention. Statistical significance of reversion to normoglycaemia and development of diabetes were assessed through comparison with expected rates without intervention.ResultsBetween baseline and 12-month follow-up HbA1c fell from 43.85 ± 1.57 mmol/mol (6.16 ± 0.14%) to 41.63 ± 3.84 mmol/mol (5.96 ± 0.35%), a decrease of 2.22 mmol/mol (0.20%) (95% CI 2.01 (0.18%), 2.42 (0.22%); p < 0.0001). The proportion of people with normal glucose tolerance at 12 months (0.50 95%CI 0.47, 0.52) was significantly larger than the lower (0.06 (p < 0.0001) and the upper (0.19 (p < 0.0001)) estimates based on no intervention.ConclusionResults indicate significant improvement in glucose tolerance across GP clusters. The brief intervention has the potential to offer a robust and effective option to support people at risk of developing type 2 diabetes. Further research in the form of a randomised trial is needed to confirm this and identify those likely to benefit most from this intervention

Accelerate [website]

‘ACCELERATE: Accessible Immersive Learning for Art and Design’ bought together art and design lecturers, educational researchers, and learning technologists from the UK, Ireland, Poland, and Ukraine to reflect on the impact of COVID-19 on higher education teaching to explore new possibilities for pedagogy and digital innovation. The project focused on the potential transformative role of immersive technologies (augmented, virtual, and extended reality) in the teaching of art and design while recognising that many learners face significant challenges in engaging effectively with XR technologies: disabilities; complex personal circumstances; low quality devices; poor and unreliable internet access. This 2-year Erasmus + ‘Strategic Partnership’ (2021-23) had a simple but ambitious aim: to improve the teaching of art and design at higher education in a post-pandemic Europe through the development of innovative methodologies, tools, platforms, and resources for accessible immersive learning. Drawing on the spirit of practice-led creative innovation, ACCELERATE created a new prototype platform for accessible immersive teaching in art and design that aimed to democratise XR technology. The collaborative development of this immersive ecosystem—open-source, scalable, sustainable—as a gateway for art and design lecturers and students with little or no previous experience of XR technologies was informed by a considered evaluation of the impact of COVID-19 on art and design teaching at the partner universities, the co-drafting of a Methodological guide, and a standalone online training course for lecturers populated with teaching materials, including co-created case studies that draw on the shared expertise and perspectives of all the project partners. By engaging with the layered complexities of XR accessibility and immersive learning, ACCELERATE has the capacity to be genuinely pioneering in its pedagogical and technological outcomes and find new ways of engaging with art and design students from disadvantaged and underrepresented groups

The pathophysiology of glucose intolerance in newly diagnosed, untreated T2DM

AimsThe two predominant pathophysiological defects resulting in glucose intolerance are beta-cell dysfunction and insulin insensitivity. This study aimed to re-examine beta-cell function and insulin sensitivity across a continuum from normal glucose tolerance (NGT) to early type 2 diabetes (T2DM) employing highly specific insulin, C-peptide and intact proinsulin assays.Materials and methodsA total of 104 persons with NGT, 85 with impaired glucose tolerance (IGT) and 554 with newly diagnosed T2DM were investigated. Following an overnight fast, all underwent a 4-h standardised mixed meal tolerance test (MTT), and on a second day, a sub-group underwent a frequently sampled insulin-modified intravenous glucose tolerance test (FSIVGTT) over a 3-h period. The participants were stratified according to fasting glucose and BMI for analysis.ResultsThe MTT revealed that increasing FPG was accompanied by progressively elevated and delayed postprandial glucose peaks. In parallel, following an initial compensatory increase in fasting and postprandial insulin responses there followed a progressive demise in overall beta-cell secretory capacity. FSIVGTT demonstrated a major reduction in the early insulin response to IV glucose in persons with IGT accompanied by a dramatic fall in insulin sensitivity. Beyond pre-diabetes, ever-increasing fasting and postprandial hyperglycaemia resulted predominantly from a progressively decreasing beta-cell secretory function.ConclusionThis study utilising improved assay technology re-affirms that beta-cell dysfunction is evident throughout the spectrum of glucose intolerance, whereas the predominant fall in insulin sensitivity occurs early in its evolution