781 research outputs found
Conscious access overflows overt report
Block proposes that phenomenal experience overflows conscious access. In contrast, we propose that conscious access overflows overt report. We argue that a theory of phenomenal experience cannot discard subjective report and that Block's examples of phenomenal "overflow" relate to two different types of perception. We propose that conscious access is more than simply readout of a preexisting phenomenal experience
Remote Sensing of Snow in the Solar Spectrum: Experiments in the French Alps.
Two experiments were perfonned irliApril and December 1992 in the French Alps using simultaneous relnote sensing and ground truth data. Snow grain site and soot content of samples collected in thefield were measured. The Landsat thematic mapper (TM) sensor was used because it has a good spatial resolution, a middle infrared channel which is sensitive to grain size and a thermal infraredchannel. Firstj the reflectance data were compared with the theoretical results obtained from a bidirectional reflectance model. Then, some remote sehstng-derived snow parameters wbre comparediWith the outpllt ofa snow metamorphism model (CROCUS),viz., lower elevation of the snowcover, lhe surface grl1in size and the surface temperature. A digital elevation model was used to obtain thelocal incidenc:f angles and the elevation of each snow pixel. The pixels were then grouped according to CROCUS classification (range, elevation, slope, and orientation) and the mean snow chart;cheracteristicsfor each class were .compared with the tROCUS results. The lower limit of snow and the surface grain size derived from TM data were compared favourably with the model results. Larger differences werefound for the temperature, because it varies rapidly and is very sensitive to shadowing by the snrrounding mountains and also because its remote measurement is dependent on atmospheric conditions
Fabrication methods for a quantum cascade photonic crystal surface emitting laser
Conventional quantum cascade (QC) lasers are intrinsically edge-emitting devices with mode confinement achieved via a standard mesa stripe configuration. Surface emission in edge emitting QC lasers has therefore necessitated redirecting the waveguided laser emission using a second order grating. This paper describes the methods used to fabricate a 2D photonic crystal (PC) structure with or without a central defect superimposed on an electrically pumped QC laser structure with the goal of achieving direct surface emission. A successful systematic study of PC hole radius and spacing was performed using e-beam lithography. This PC method offers the promise of a number of interesting applications, including miniaturization and integration of QC lasers
Fabrication technologies for quantum cascade photonic-crystal microlasers
In this paper we describe the technological and fabrication methods necessary to incorporate both photonic and electronic-band engineering in order to create novel surface-emitting quantum cascade microcavity laser sources. This technology offers the promise of several innovative applications such as the miniaturization of QC lasers, and multi-wavelength two-dimensional laser arrays for spectroscopy, gas-sensing and imaging. This approach is not limited to light-emitting devices, and may be efficiently applied to the development of mid- and far-infrared normal-incidence detectors
Quantum cascade photonic crystal surface emitting injection laser
A surface emitting quantum cascade injection laser is presented. Direct surface emission is obtained by using a 2D photonic-band-gap structure that simultaneously acts as a microcavity. The approach may allow miniaturization and on-chip-integration of the devices
Quelle rĂ©gulation pour lâarrĂȘt dâun protocole de recherche clinique de thĂ©rapie gĂ©nique somatique ? Ătat des lieux auprĂšs des cliniciens-chercheurs europĂ©ens
Depuis 2002, le dĂ©bat sur les risques associĂ©s Ă la thĂ©rapie gĂ©nique est initiĂ© suite Ă lâannonce
que deux enfants inclus dans un essai thérapeutique impliquant une thérapie génique ont
développé des effets indésirables important. En Janvier 2005, le débat sur les risques reprit suite
Ă lâinterruption du protocole sur les enfants bulle du Pr Fischer Ă lâhĂŽpital Necker de Paris. Nous
avons donc étudié le processus impliqué ainsi que la réflexion éthique associée aux décisions
dâarrĂȘt de protocole de recherche. Notre travail a Ă©tĂ© menĂ© par une Ă©quipe pluridisciplinaire
combinant chercheurs en santé, généticiens et éthiciens. Nous avons étudié la participation des
chercheurs, des patients, des institutions officielles, des comitĂ©s dâĂ©thique ainsi que des
associations de patients dans le processus de dĂ©cision dâinterruption dâun protocole de recherche.Nous avons Ă©galement analysĂ© les critĂšres jugĂ©s les plus pertinents dans lâarrĂȘt dâun protocole
de recherche. Enfin nous avons analysé le point de vue des personnes directement impliquées
dans la thĂ©rapie gĂ©nique au moyen dâun questionnaire. Toutes les personnes contactĂ©es ont
présenté un poster de recherche au congrÚs de la Société Européenne de Thérapie Génique. 62
personnes dâautant dâĂ©quipes de recherche diffĂ©rentes, de 17 pays, sur les 350 contactĂ©s ont
rĂ©pondu. Selon eux, la dĂ©cision dâarrĂȘt dâun protocole de recherche doit ĂȘtre prise suite Ă une
consultation des chercheurs, des patients, du ministĂšre de tutelle, dâune agence nationale de
rĂ©gulation ou dâun comitĂ© dâĂ©thique ; la lĂ©gitimitĂ© Ă©tant accordĂ©e Ă des dĂ©cisions prises en
commun par les chercheurs, les patients et les comitĂ©s dâĂ©thique. Les incidents sĂ©rieux et de façon
plus surprenante, les incidents moins graves sont jugés comme étant des critÚres suffisants pour
interrompre un essai. Nous avons fini par analyser les conséquences éthiques, telles que balance
bĂ©nĂ©fice/risque, processus de rĂ©gulation ou responsabilitĂ©, de ces critĂšres sur lâarrĂȘt dâun protocole
de recherche.In 2002, the debate on the risks of gene therapy was initiated following the annoucement that two
children included in a clinical trial developed serious adverse effects. In January 2005, the debate
was reignited following the interruption of the âbubble kids protocolâ at the HĂŽpital Necker in Paris.
We have thus investigated the ethical stakes involved in decisions to stop protocols. This work was
carried out by a multidisciplinary team combining ethics researchers and geneticists. We studied
the specific participation of researchers, patients, official institution, ethics committees and patient
associations in the processes that can lead to an interruption of trial.We also analysed the criterion
judged most relevant for halting a trial. Finally, we analyzed the perspective of the actors implicated
directly in the provision of gene therapy, by means of a questionnaire. All the individuals contacted
had presented a scientific poster at the European Society of Gene Therapy. 62 out of 350 persons,
from 17 countries, responded to our questionnaire. According to these respondants, decisions to stop
a trial should be taken after consultation with researchers, patients, the ministry, national agencies
or ethics committees. Legitimacy was accorded to joint decision-making by researchers, patients and
committees. Serious incidents, and surprisingly less serious incidents, clearly emerge as criterion for
stopping a trial. We conclude by analyzing the ethical consequences, such as risk/benefit ratios,
regulatory processes and responsibility, associated with these criterions and decisions to stop a trial
Far-infrared surface-plasmon quantum-cascade lasers at 21.5 mu m and 24 mu m wavelengths
Quantum-cascade lasers operating above 20 mum (at lambda similar to 21.5 mum and lambda similar to 24 mum) wavelength are reported. Pulsed operation was obtained up to 140 K and with a peak power of a few milliwatts at cryogenic temperatures. Laser action originates from interminiband transitions in "chirped" superlattice active regions. The waveguides are based on surface-plasmon modes confined at a metal-semiconductor interface. The wavelengths were chosen in order to avoid major phonon absorption bands, which are particularly strong at energies just above the reststrahlen band. We also report on a 21.5-mum-wavelength laser based on a two-sided interface-plasmon waveguide. (C) 2001 American Institute of Physics
Reversible protein precipitation to ensure stability during encapsulation within PLGA microspheres
Proteins were precipitated to ensure their stability upon subsequent encapsulation within PLGA microspheres. Spherical, nanosized protein particles were formed by the addition of a salt (sodium chloride) and a water-miscible organic solvent (glycofurol) to protein solutions. Various process parameters were modified to optimize the precipitation efficiency of four model proteins: lysozyme, alpha-chymotrypsin, peroxidase and beta-galactosidase. As monitored by enzymatic activity measurement of the rehydrated particles, conditions to obtain more than 95% of reversible precipitates were defined for each protein. The study of the structure of the rehydrated particles by absorbance spectroscopy, fluorescence spectroscopy and circular dichroism showed an absence of structural-perturbation after precipitation. Protein particles were then microencapsulated within PLGA microspheres using s/o/w technique. The average encapsulation yield was around 80% and no loss of protein activity occurred after the encapsulation step. Additionally, a lysozyme in vitro release study showed that all of the released lysozyme was biologically active. This method of protein precipitation is appropriate for the encapsulation in PLGA microspheres of various proteins without inactivation
Longer fixation duration while viewing face images
The spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity. We recorded monkeysâ saccadic eye movements as they freely viewed monkey face and natural scene images. The face and natural scene images attracted similar number of fixations, but viewing of faces was accompanied by longer fixations compared with natural scenes. These longer fixations were dependent on the context of facial features. The duration of fixations directed at facial contours decreased when the face images were scrambled, and increased at the later stage of normal face viewing. The results suggest that face and natural scene images can generate different patterns of visuomotor activity. The extra fixation duration on faces may be correlated with the detailed analysis of facial features
Sensitivity analysis of erosion on the landward slope of an earthen flood defense located in southern France submitted to wave overtopping
The study aims to provide a complete analysis framework applied to an earthen dike located in Camargue, France. This dike is regularly submitted to erosion on the landward slope that needs to be repaired.
Improving the resilience of the dike calls for a reliable model of damage frequency. The developed system is a combination of copula theory, empirical wave propagation, and overtopping equations as well as a global sensitivity analysis in order to provide the return period of erosion damage on a set dike while also providing recommendations in order for the dike to be reinforced as well as the model to be self-improved. The global sensitivity analysis requires one to calculate a high number of return periods over random observations of the tested parameters. This gives a distribution of the return periods, providing a more general approach to the behavior of the dike. The results show a return period peak around the 2-year mark, close to reported observation. With the distribution being skewed, the mean value is higher and is thus less reliable as a measure of dike safety. The results of the global sensitivity analysis show that no particular category of dike features contributes significantly more to the uncertainty of the system. The highest contributing factors are the dike height, the critical velocity, and the coefficient of seaward slope roughness. These results underline the importance of good dike characterization in order to improve the predictability of return period estimations. The obtained return periods have been confirmed by current in situ observations, but the uncertainty increases for the most severe events due to the lack of long-term data.</p
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