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Fast response time fiber optical pH and oxygen sensors
While fluorescence-based fiber optic sensors for measuring both pH and oxygen concentration (O2) are well known, current sensors are often limited by their response time and drift, which limits the use of existing fiber optic sensors of this type in wider applications, for example in physiology and other fields. Several new fiber optical sensors have been developed and optimized, with respect to key features such as tip shape and coating layer thickness. In this work, preliminary results on the performance of a suite of pH sensors with fast response times, < 3 second and oxygen sensors (O2) with response times < 0.2 second. The sensors have been calibrated and their performance analyzed using the Henderson–Hasselbalch equation (pH) and classic Lehrer-model (O2)
Improved model for the analysis of air fluorescence induced by electrons
A model recently proposed for the calculation of air-fluorescence yield
excited by electrons is revisited. Improved energy distributions of secondary
electrons and a more realistic Monte Carlo simulation including some additional
processes have allowed us to obtain more accurate results. The model is used to
study in detail the relationship between fluorescence intensity and deposited
energy in a wide range of primary energy (keVs - GeVs). In addition,
predictions on the absolute value of the fluorescence efficiency in the absence
of collisional quenching will be presented and compared with available
experimental data.Comment: Contribution to the 5th Fluorescence Workshop, El Escorial, Madrid,
Spain, September 2007, to appear in Nuclear Instruments and Methods A.
Revised version.- More details on the comparison with experimental dat
Comparison of available measurements of the absolute fluorescence yield
The uncertainty in the absolute value of the fluorescence yield is still one
of the main contributions to the total error in the reconstruction of the
primary energy of ultra-energetic air showers using the fluorescence technique.
A significant number of experimental values of the fluorescence yield have been
published in the last years, however reported results are given very often in
different units (photons/MeV or photons/m) and for different wavelength
intervals. In this work we present a comparison of available results normalized
to its value in photons/MeV for the 337 nm band at 800 hPa and 293 K. The
conversion of photons/m to photons/MeV requires an accurate determination of
the energy deposited by the electrons in the field of view of the experimental
setup. We have calculated the energy deposition for each experiment by means of
a detailed Monte Carlo simulation including when possible the geometrical
details of the particular setup. Our predictions on deposited energy, as well
as on some geometrical factors, have been compared with those reported by the
authors of the corresponding experiments and possible corrections to the
fluorescence yields are proposed.Comment: 29 pages, 5 figures Revised version submitted to Astroparticle
Physic
Evidence for virtual Compton scattering from the proton
In virtual Compton scattering an electron is scattered off a nucleon such that the nucleon emits a photon. We show that these events can be selected experimentally, and present the first evidence for virtual Compton scattering from the proton in data obtained at the Stanford Linear Accelerator Center. The angular and energy dependence of the data is well described by a calculation that includes the coherent sum of electron and proton radiation
Psychothérapie de la dépression chronique: l'apport du modèle CBASP selon McCullough = Psychotherapy of chronic depression: Contributions of CBASP by McCullough
Les dépressions chroniques sont fréquentes et souvent traitées par des approches traditionnelles. Cet article vise à présenter la nature spécifique de la psychopathologie et un traitement spécifiquement adapté à ces patients avec dépression chronique. Nous décrirons d'abord les spécificités psychopathologiques de cette population, en nous référant aux travaux de J. Piaget et de D. Kiesler. À partir de ces théories, nous mettrons en avant le modèle Cognitive Behavioral Analysis System of Psychotherapy (CBASP), selon McCullough. Cet auteur propose deux volets d'interventions spécifiquement adaptées aux patients avec dépression chronique : l'analyse situationnelle et les techniques interpersonnelles basées sur la notion de transfert et de contre-transfert. Nous soulignerons la pertinence de cette approche par le résumé de plusieurs études empiriques ayant établi l'efficacité de ce modèle, sous certaines conditions cliniques. Nous terminerons par une réflexion de l'application de ce modèle au-delà du tableau clinique de la dépression chronique en ajoutant ainsi des arguments supplémentaires en faveur de l'apport du modèle CBASP au champ actuel de la psychothérapie des troubles mentaux. © L'Encéphale, Paris, 2012
The stable phases of the Cs2CuCl4-xBrx mixed systems
Starting from Cs2CuCl4 and Cs2CuBr4 our project focuses on the growth of the
Cs2CuCl4-xBrx mixed crystals from aqueous solution and the investigation of the
occurring structural variations. The well known orthorhombic structure (space
group Pnma) of the end members of this system is interrupted within the
intermediate composition range Cs2CuCl3Br1 - Cs2CuCl2Br2, if the growth takes
place at room temperature. Within this range a new tetragonal phase is found
(space group I4/mmm). However, in case the growth temperature will be increased
to 50 {\deg}C, the existence of the orthorhombic structure can be extended over
the whole Cs2CuCl4-xBrx mixed system. A detailed analysis of the composition
dependence of the lattice parameters is used to draw conclusions on the
incorporation of Cl- and Br-ions at different sites which is important for the
magnetic interactions between the Cu-ions.Comment: 16 pages,8 figure
Multiple Dendritic Cell Populations Activate CD4+ T Cells after Viral Stimulation
Dendritic cells (DC) are a heterogeneous cell population that bridge the innate and adaptive immune systems. CD8α DC play a prominent, and sometimes exclusive, role in driving amplification of CD8+ T cells during a viral infection. Whether this reliance on a single subset of DC also applies for CD4+ T cell activation is unknown. We used a direct ex vivo antigen presentation assay to probe the capacity of flow cytometrically purified DC populations to drive amplification of CD4+ and CD8+ T cells following infection with influenza virus by different routes. This study examined the contributions of non-CD8α DC populations in the amplification of CD8+ and CD4+ T cells in cutaneous and systemic influenza viral infections. We confirmed that in vivo, effective immune responses for CD8+ T cells are dominated by presentation of antigen by CD8α DC but can involve non-CD8α DC. In contrast, CD4+ T cell responses relied more heavily on the contributions of dermal DC migrating from peripheral lymphoid tissues following cutaneous infection, and CD4 DC in the spleen after systemic infection. CD4+ T cell priming by DC subsets that is dependent upon the route of administration raises the possibility that vaccination approaches could be tailored to prime helper T cell immunity
Evaluating Conversational Recommender Systems via User Simulation
Conversational information access is an emerging research area. Currently,
human evaluation is used for end-to-end system evaluation, which is both very
time and resource intensive at scale, and thus becomes a bottleneck of
progress. As an alternative, we propose automated evaluation by means of
simulating users. Our user simulator aims to generate responses that a real
human would give by considering both individual preferences and the general
flow of interaction with the system. We evaluate our simulation approach on an
item recommendation task by comparing three existing conversational recommender
systems. We show that preference modeling and task-specific interaction models
both contribute to more realistic simulations, and can help achieve high
correlation between automatic evaluation measures and manual human assessments.Comment: Proceedings of the 26th ACM SIGKDD Conference on Knowledge Discovery
and Data Mining (KDD '20), 202
Air fluorescence measurements in the spectral range 300-420 nm using a 28.5 GeV electron beam
Measurements are reported of the yield and spectrum of fluorescence, excited
by a 28.5 GeV electron beam, in air at a range of pressures of interest to
ultra-high energy cosmic ray detectors. The wavelength range was 300 - 420 nm.
System calibration has been performed using Rayleigh scattering of a nitrogen
laser beam. In atmospheric pressure dry air at 304 K the yield is 20.8 +/- 1.6
photons per MeV.Comment: 29 pages, 10 figures. Submitted to Astroparticle Physic
Extending the applicability of the dose addition model to the assessment of chemical mixtures of partial agonists by using a novel toxic unit extrapolation method
This article has been made available through the Brunel Open Access Publishing Fund.Dose addition, a commonly used concept in toxicology for the prediction of chemical mixture effects, cannot readily be applied to mixtures of partial agonists with differing maximal effects. Due to its mathematical features, effect levels that exceed the maximal effect of the least efficacious compound present in the mixture, cannot be calculated. This poses problems when dealing with mixtures likely to be encountered in realistic assessment situations where chemicals often show differing maximal effects. To overcome this limitation, we developed a pragmatic solution that extrapolates the toxic units of partial agonists to effect levels beyond their maximal efficacy. We extrapolated different additivity expectations that reflect theoretically possible extremes and validated this approach with a mixture of 21 estrogenic chemicals in the E-Screen. This assay measures the proliferation of human epithelial breast cancers. We found that the dose-response curves of the estrogenic agents exhibited widely varying shapes, slopes and maximal effects, which made it necessary to extrapolate mixture responses above 14% proliferation. Our toxic unit extrapolation approach predicted all mixture responses accurately. It extends the applicability of dose addition to combinations of agents with differing saturating effects and removes an important bottleneck that has severely hampered the use of dose addition in the past. © 2014 Scholze et al
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