3,324 research outputs found
Some aspects of electronâphonon interaction in the thermal modulation spectra of molecular crystals
The details of the temperature dependent intensity and linewidth of zeroâphonon bands in molecular crystal absorption and emission spectra are considered in relation to the line shape functions observed in thermal modulation spectra. Theory suggests and experiment confirms that in the limit of the Condon and adiabatic approximations for linear electronâphonon coupling, the extraordinary temperature dependence of zeroâphonon bands may be utilized to separate them from diffuse background absorption or emission. Qualitative consideration of line broadening from quadratic electronâphonon coupling utilizing a configuration coordinate model suggests that even when these terms dominate the linear interaction, increased resolution may be obtained in a thermal modulation spectrum. The theoretical considerations are illustrated with several experimental examples and some applications of the technique are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70661/2/JCPSA6-65-12-5068-1.pd
Concave Plasmonic Particles: Broad-Band Geometrical Tunability in the Near Infra-Red
Optical resonances spanning the Near and Short Infra-Red spectral regime were
exhibited experimentally by arrays of plasmonic nano-particles with concave
cross-section. The concavity of the particle was shown to be the key ingredient
for enabling the broad band tunability of the resonance frequency, even for
particles with dimensional aspect ratios of order unity. The atypical
flexibility of setting the resonance wavelength is shown to stem from a unique
interplay of local geometry with surface charge distributions
Automatic image acquisition, calibration and montage assembly for biological X-ray microscopy
Summary We describe a system for the automatic acquisition and processing of digital images in a high-resolution X-ray microscope, including the formation of large-Âźeld highresolution image montages. A computer-controlled sample positioning stage provides approximate coordinates for each high-resolution subimage. Individual subimages are corrected to compensate for time-varying, non-uniform illumination and CCD-related artefacts. They are then automatically assembled into a montage. The montage assembly algorithm is designed to use the overlap between each subimage and multiple neighbours to improve the performance of the registration step and the Âźdelity of the result. This is accomplished by explicit use of recorded stage positions, optimized ordering of subimage insertion, and registration of subimages to the developing montage. Using this procedure registration errors are below the resolution limit of the microscope (43 nm). The image produced is a seamless, large-Âźeld montage at full resolution, assembled automatically without human intervention. Beyond this, it is also an accurate X-ray transmission map that allows the quantitative measurement of anatomical and chemical features of the sample. Applying these tools to a biological problem, we have conducted the largest X-ray microscopical study to date
Subcutaneous ketamine infusion in palliative patients for major depressive disorder (SKIPMDD)âPhase II single-arm open-label feasibility study
Background Ketamine at subanaesthetic dosages ( 18-years-old) with advanced life-limiting illnesses referred to four palliative care services in Sydney, Australia, diagnosed with major depressive disorder from any care setting. Participants received weekly subcutaneous ketamine infusion (0.1â0.4mg/kg) over two hours using individual dose-titration design. Outcomes assessed were feasibility, safety, tolerability and antidepressant activity. Results Out of ninety-nine referrals, ten participants received ketamine and were analysed for responses. Accrual rate was 0.54 participants/month across sites with 50% of treated participants achieving > 50% reduction in baseline Montgomery-Ă
sberg Depression Rating Scale, meeting feasibility criteria set a priori. There were no clinically relevant harms encountered. Conclusions A future definitive trial exploring the effectiveness of subcutaneous infusion of ketamine for major depressive disorder in the palliative care setting may be feasible by addressing identified study barriers. Individual dose-titration of subcutaneous ketamine infusions over two hours from 0.1mg/kg can be well-tolerated and appears to produce transient antidepressant signals over hours to days
Rigorous Real-Time Feynman Path Integral for Vector Potentials
we will show the existence and uniqueness of a real-time, time-sliced Feynman
path integral for quantum systems with vector potential. Our formulation of the
path integral will be derived on the transition probability amplitude via
improper Riemann integrals. Our formulation will hold for vector potential
Hamiltonian for which its potential and vector potential each carries at most a
finite number of singularities and discontinuities
Low prevalence of non-typable Methicillin-resistant Staphylococcus aureus in meat products in The Netherlands
Recently, a new clone of methicillin resistant Staphylococcus (S.) aureus (MRSA) emerged in the Netherlands that was related to pigfarming. A survey in pigs showed that nearly 40% carried this new clone. This new type is characterised by bemg untypable with pulsed field gel electrophoresis (PFGE). This study was undertaken to determme the prevalence and genetic relationship of S.aureus and MRSA in meal products
The reflective learning continuum: reflecting on reflection
The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research which considers reflection within the context of both the marketing and general business education literature. This paper describes the use of an instrument which can be used to measure four identified levels of a reflection hierarchy: habitual action, understanding, reflection and intensive reflection and two conditions for reflection: instructor to student interaction and student to student interaction. Further we demonstrate the importance of reflective learning in predicting graduatesâ perception of program quality. Although the focus was on assessment of MBA level curricula, the findings have great importance to marketing education and educators
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