5,166 research outputs found
Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus
Strong 10 micrometer line emission from (c-12)(o-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features
Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus
Strong 10 micrometer line emission from (C-12)(O-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features
Assistant practitioners (APs) perceptions of their developing role and practice in radiography: Results from a national survey
Introduction: In 2000, the NHS Plan set out the government's plans for investment and reform across the NHS. Through the introduction of a new workforce at assistant practitioner (AP) level the Department of Health intended to implement new ways in which to deliver a more efficient service. At the time, little published information existed on the integration of these assistants into the contemporary radiography workforce. Publications were limited to experiences gained by various individual departments ranging in their perception of the role and education of APs. Further research was suggested to track the continuing implementation of the 4-tier structure, establish the precise nature and scope of the roles across Trusts and determine their impact on workload and patient care. Aim: To establish the number and employment locality of APs in radiography professions in England, and to explore their scope of applied practice. Method and materials: The study was conducted over three phases and employed a mixed methods design to address the aims and objectives. Phase I was a scoping exercise performed prior to data collection in which n = 226 radiography sites were identified for contact across England. Phase II utilized a questionnaire as data collection tool to investigate the role of APs in radiography and explore how their roles were integrated into the radiography workforce in England. Results from phase III of the study which utilized semi-structured qualitative interviews are not included in this paper. Conclusion and discussion: Key findings depict the nature and variety of roles and responsibilities undertaken by APs in radiography. This study was the first of its kind to identify the integration of APs in radiography across a sizable geographical region. There were mixed responses to the question asking APs if they were required to perform duties outside their scope of practice. Questionnaire data revealed that a high numbers of APs were working in areas under indirect supervision. Results from this study showed that APs, in some areas at least, were performing the roles of practitioners. Therefore further investigation is needed for new roles to develop criteria to determine which new roles should be the subject of statutory regulation. © 2011 The College of Radiographers
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Using transcranial Direct Current Stimulation (tDCS) to modulate the face inversion effect on the N170 ERP component
This is the final version. Available from the Cognitive Science Society via the link in this recordIn the present study, we combined tDCS and EEG to examine the
electrophysiological responses to the tDCS-induced effects on
the face inversion effect showed in recent studies. A double-blind
procedure with a between-subjects design (n=48) was used with
the subjects, recruited from the student population, being
randomly assigned to either tDCS anodal or sham condition. The
tDCS stimulation was delivered over the DLPFC at Fp3 site for
10 min at an intensity of 1.5mA while subjects engaged in an
old/new recognition task traditionally used to obtain the
inversion effect. The behavioural results generally confirmed
previous findings. Critically, the results from the N170 show an
effect of tDCS. Specifically, the tDCS procedure was able to
modulate the N170 peak component by reducing the inversion
effect on the latencies (i.e. less delay between upright and
inverted faces) and by increasing the inversion effect on the
amplitudes (i.e. larger N170 for inverted vs upright faces). We
interpret the results based on the previous literature in regard to
the inversion effect on the N170 component.European Union Horizon 2020Economic and Social Research Council (ESRC
The effect of scrambling upright and inverted faces on the N170
This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.The face inversion effect refers to a decrement in performance when we try to recognise
familiar faces turned upside down (inverted), compared to familiar faces presented in their usual
(upright) orientation. Recently, we have demonstrated that the inversion effect can also be found
with checkerboards drawn from prototype-defined categories when the participants have been
trained with these categories, suggesting that factors such as expertise and the relationships
between stimulus features, may be important determinants of this effect. We also demonstrated
that the typical inversion effect on the N170 seen with faces is found with checkerboards,
suggesting that modulation of the N170 is a marker for disruption in the use of configural
information. In the present experiment, we first demonstrate that our scrambling technique
greatly reduces the inversion effect in faces. Following this, we used Event-Related Potentials
(ERPs) recorded while participants performed an Old/New recognition study on normal and
scrambled faces presented in both upright and inverted orientations to investigate the impact of
scrambling on the N170. We obtained the standard robust inversion effect for normal faces: The
N170 was both larger and delayed for normal inverted faces as compared to normal upright
faces, whereas a significantly reduced inversion effect was recorded for scrambled faces. These
results show that the inversion effect on the N170 is greater for normal compared to scrambled
faces, and we interpret the smaller effect for scrambled faces as being due to the reduction in
expertise for those faces consequent on scramblingThis project has received funding from the European Union’s Horizon 2020 research and
innovation programme under the Marie Sklodowska-Curie grant agreement No 74370
The effect of tDCS on recognition depends on stimulus generalization: Neuro-stimulation can predictably enhance or reduce the face inversion effect
This is the author accepted manuscript. The final version is available from the American Psychological Association via the DOI in this recordThis paper reports results from three experiments that investigate how a particular neurostimulation procedure is able, in certain circumstances, to selectively increase the face inversion
effect by enhancing recognition for upright faces, and argues that these effects can be understood
in terms of the MKM theory of stimulus representation. We demonstrate how a specific
transcranial Direct Current Stimulation (tDCS) methodology can improve performance in
circumstances where error-based salience modulation is making face recognition harder. The
three experiments used an old/new recognition task involving sets of normal vs Thatcherised
faces. The main characteristic of Thatcherised faces is that the eyes and the mouth are upside
down, thus emphasizing features that tend to be common to other Thatcherised faces and so
leading to stronger generalization making recognition worse. Experiment 1 combined a
behavioural and ERP study looking at the N170 peak component, which helped us to calibrate
the set of face stimuli needed for subsequent experiments. In Experiment 2 we used our tDCS
procedure (between-subjects and double-blind) in an attempt to reduce the negative effects
induced by error-based modulation of salience on recognition of upright Thatcherised faces.
Results largely confirmed our predictions. In addition, they showed a significant improvement on
recognition performance for upright normal faces. Experiment 3 provides the first direct
evidence in a single study that the same tDCS procedure is able to both enhance performance
when normal faces are presented with Thatcherised faces, and to reduce performance when
normal faces are presented with other normal faces (i.e. male vs female faces). We interpret our
results by analyzing how salience modulation influences generalization between similar
categories of stimuli.European Union Horizon 2020Economic and Social Research Council (ESRC
Directional cue and landmark configurations: The effect of rotating one set of landmarks relative to another
This is the author accepted manuscript. The final version is available from the American Psychological Association via the DOI in this recordIn this article we addressed the question whether rats can use distal landmarks as directional cues that are used in combination with other proximal landmark configurations. The animals were trained with an A, B, C, and D landmark configuration in the Morris pool, where B and C are the near (to platform) landmarks and A and D the far ones. We also added another more distal "directional" cue Z (a white strip attached to the black curtain surrounding the pool). Experiment 1 shows a robust detrimental effect on the time spent by the rats swimming in the platform quadrant when the location of all landmarks was "Inverted" (rotated by 180 degrees) with respect to Z. A similar detrimental effect was found when, after the inversion manipulation, the locations of the near and far landmarks were "Flipped" (B swapped with C and A with D). Rats in both Inverted and Flipped tests spent more time in the Z quadrant compared to the platform quadrant (BC). Experiment 1b provided evidence distinguishing between alternative explanations of how the directional cue Z acts in combination with the other landmarks. The results from both experiments show that Z operates differently to the standard landmarks. It can function as a beacon in its own right. It can also combine with the other landmarks to produce a high level of search performance, in a way that we hypothesize to be distinct from that described by the configural analysis often applied to multiple landmarks.European Union Horizon 2020Economic and Social Research Council (ESRC
Mackintosh lecture: Association and cognition: two processes, one system
This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.There is another ORE record for this item: http://hdl.handle.net/10871/33264This paper argues that the dual-process position can be a useful first approximation
when studying human mental life, but it cannot be the whole truth. Instead, we argue
that cognition is built on association, in that associative processes provide the
fundamental building blocks that enable propositional thought. One consequence of
this position is to suggest that humans are able to learn associatively in a similar
fashion to a rat or a pigeon, but another is that we must typically suppress the
expression of basic associative learning in favour of rule-based computation. This
stance conceptualizes us as capable of symbolic computation, but acknowledges that,
given certain circumstances, we will learn associatively and, more importantly, be
seen to do so. We present three types of evidence that support this position: The first
is data on human Pavlovian conditioning that directly supports this view. The second
is data taken from task switching experiments that provides convergent evidence for
at least two modes of processing, one of which is automatic and carried out “in the
background”. And the last suggests that when the output of propositional processes is
uncertain, then the influence of associative processes on behaviour can manifest
Measuring the Non-Separability of Optical Fields
Across various areas in the optical world, there has been a growing interest in exploiting the properties of non-separable optical fields. A class of non-separable fields, known as vector modes, exhibit a coupling between the spatial and polarisation degrees of freedom that is akin of entanglement in quantum mechanics. These vector modes, however, are typically characterized using qualitative measurements which are inadequate in determining to what extent an optical field is non-separable. Here, we present tools to characterize the degree of non-separability of an arbitrary optical field, exploiting the similarities between vector modes and quantum entangled states. As an example, we use vector modes carrying orbital angular momentum to demonstrate the effectiveness of our scheme, and note that the approach can be generalized to vector modes as a whole
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