139 research outputs found
Training the Forgetting of Negative Material: The Role of Active Suppression and the Relation to Stress Reactivity
In this study, the authors investigated whether training participants to use cognitive strategies can aid forgetting in depression. Participants diagnosed with major depressive disorder (MDD) and never-depressed participants learned to associate neutral cue words with a positive or negative target word and were then instructed not to think about the negative targets when shown their cues. The authors compared 3 different conditions: an unaided condition, a positive-substitute condition, and a negative-substitute condition. In the substitute conditions, participants were instructed to use new targets to keep from thinking about the original targets. After the trainingphase, participants were instructed to recall all targets when presented with the cues. MDD participants, in contrast with control participants, did not exhibit forgetting of negative words in the unaided condition. In both the negative and positive substitute conditions, however, MDD participants showed successful forgetting of negative words and a clear practice effect. In contrast, negative substitute words did not aid forgetting by the control participants. These findings suggest that training depressed individuals to use cognitive strategies can increase forgetting of negative words
Resonant Metalenses for Breaking the Diffraction Barrier
We introduce the resonant metalens, a cluster of coupled subwavelength
resonators. Dispersion allows the conversion of subwavelength wavefields into
temporal signatures while the Purcell effect permits an efficient radiation of
this information in the far-field. The study of an array of resonant wires
using microwaves provides a physical understanding of the underlying mechanism.
We experimentally demonstrate imaging and focusing from the far-field with
resolutions far below the diffraction limit. This concept is realizable at any
frequency where subwavelength resonators can be designed.Comment: 4 pages, 3 figure
Training Forgetting of Negative Material in Depression
In this study, the authors investigated whether training participants to use cognitive strategies can aid forgetting in depression. Participants diagnosed with major depressive disorder (MDD) and never-depressed participants learned to associate neutral cue words with a positive or negative target word and were then instructed not to think about the negative targets when shown their cues. The authors compared 3 different conditions: an unaided condition, a positive-substitute condition, and a negative-substitute condition. In the substitute conditions, participants were instructed to use new targets to keep from thinking about the original targets. After the training phase, participants were instructed to recall all targets when presented with the cues. MDD participants, in contrast with control participants, did not exhibit forgetting of negative words in the unaided condition. In both the negative and positive substitute conditions, however, MDD participants showed successful forgetting of negative words and a clear practice effect. In contrast, negative substitute words did not aid forgetting by the control participants. These findings suggest that training depressed individuals to use cognitive strategies can increase forgetting of negative words
The rise of fully turbulent flow
Over a century of research into the origin of turbulence in wallbounded shear
flows has resulted in a puzzling picture in which turbulence appears in a
variety of different states competing with laminar background flow. At slightly
higher speeds the situation changes distinctly and the entire flow is
turbulent. Neither the origin of the different states encountered during
transition, nor their front dynamics, let alone the transformation to full
turbulence could be explained to date. Combining experiments, theory and
computer simulations here we uncover the bifurcation scenario organising the
route to fully turbulent pipe flow and explain the front dynamics of the
different states encountered in the process. Key to resolving this problem is
the interpretation of the flow as a bistable system with nonlinear propagation
(advection) of turbulent fronts. These findings bridge the gap between our
understanding of the onset of turbulence and fully turbulent flows.Comment: 31 pages, 9 figure
Early evolution of the extraordinary Nova Del 2013 (V339 Del)
We determine the temporal evolution of the luminosity L(WD), radius R(WD) and
effective temperature Teff of the white dwarf (WD) pseudophotosphere of V339
Del from its discovery to around day 40. Another main objective was studying
the ionization structure of the ejecta. These aims were achieved by modelling
the optical/near-IR spectral energy distribution (SED) using low-resolution
spectroscopy (3500 - 9200 A), UBVRcIc and JHKLM photometry. During the fireball
stage (Aug. 14.8 - 19.9, 2013), Teff was in the range of 6000 - 12000 K, R(WD)
was expanding non-uniformly in time from around 66 to around 300 (d/3 kpc)
R(Sun), and L(WD) was super-Eddington, but not constant. After the fireball
stage, a large emission measure of 1.0-2.0E+62 (d/3 kpc)**2 cm**(-3)
constrained the lower limit of L(WD) to be well above the super-Eddington
value. The evolution of the H-alpha line and mainly the transient emergence of
the Raman-scattered O VI 1032 A line suggested a biconical ionization structure
of the ejecta with a disk-like H I region persisting around the WD until its
total ionization, around day 40. It is evident that the nova was not evolving
according to the current theoretical prediction. The unusual non-spherically
symmetric ejecta of nova V339 Del and its extreme physical conditions and
evolution during and after the fireball stage represent interesting new
challenges for the theoretical modelling of the nova phenomenon.Comment: 14 pages, 9 figures, 3 tables, accepted for Astronomy and
Astrophysic
Feasibility criteria for total thyroidectomy in outpatient surgery
INTRODUCTION: France is pursuing a policy of cutting healthcare costs, and outpatient surgery is one of the objectives of this policy. Thyroid surgery could be suitable for outpatient management, provided there is an appropriate patient selection process. The aim of this study was to assess the risk factors for postoperative complications in total thyroidectomy (TT).
DESIGN: A single-center observational study was carried out from January 2010 to December 2015.
METHOD: Correlations between, on the one hand, age, gender, obesity, history of surgery, antiplatelet and/or anticoagulation treatment, the surgeon\u27s experience, surgery time, repeated lymph node dissection, and surgical indication (cancer, lymphocytic thyroiditis, Graves\u27 disease or multinodular goiter) and, on the other hand, onset of postoperative complications (postoperative hypocalcemia, uni- or bi-lateral lesions of the recurrent laryngeal nerves, and premature compressive hematoma) were assessed.
RESULTS: Four hundred and twenty-four consecutive TTs were included. 85 patients showed postoperative hypocalcemia (20.04%), 18 recurrent laryngeal nerve lesion (4.25%), and 4 compressive cervical hematoma (0.94%). Overall morbidity was 24.06%. Risk factors identified for postoperative hypocalcemia comprised: female gender [OR=3.2584; 95%CI (1.5500-7.7515); P=0.0036], surgery time [OR=1.0095; 95%CI (1.0020-1.0172); P=0.0129], and surgical indication for benign adenoma [OR=5.0642; 95%CI (1.7768-14.5904); P=0.0022]. None of the study variables emerged as risk factors for recurrent laryngeal nerve lesion. Repeated dissection increased the risk of re-do surgery for compressive hematoma [OR=25.1373; 95%CI (0.8468-32.2042); P=0.0347].
CONCLUSION: Surgery time, female gender, repeated dissection and total thyroidectomy for benign adenoma are risk factors that should be considered in decision-making for performing TT on an outpatient basis
Focusing and Compression of Ultrashort Pulses through Scattering Media
Light scattering in inhomogeneous media induces wavefront distortions which
pose an inherent limitation in many optical applications. Examples range from
microscopy and nanosurgery to astronomy. In recent years, ongoing efforts have
made the correction of spatial distortions possible by wavefront shaping
techniques. However, when ultrashort pulses are employed scattering induces
temporal distortions which hinder their use in nonlinear processes such as in
multiphoton microscopy and quantum control experiments. Here we show that
correction of both spatial and temporal distortions can be attained by
manipulating only the spatial degrees of freedom of the incident wavefront.
Moreover, by optimizing a nonlinear signal the refocused pulse can be shorter
than the input pulse. We demonstrate focusing of 100fs pulses through a 1mm
thick brain tissue, and 1000-fold enhancement of a localized two-photon
fluorescence signal. Our results open up new possibilities for optical
manipulation and nonlinear imaging in scattering media
Controlling waves in space and time for imaging and focusing in complex media
In complex media such as white paint and biological tissue, light encounters nanoscale refractive-index inhomogeneities that cause multiple scattering. Such scattering is usually seen as an impediment to focusing and imaging. However, scientists have recently used strongly scattering materials to focus, shape and compress waves by controlling the many degrees of freedom in the incident waves. This was first demonstrated in the acoustic and microwave domains using time reversal, and is now being performed in the optical realm using spatial light modulators to address the many thousands of spatial degrees of freedom of light. This approach is being used to investigate phenomena such as optical super-resolution and the time reversal of light, thus opening many new avenues for imaging and focusing in turbid medi
Positive Shifts in Emotion Evaluation Following Mindfulness-Based Cognitive Therapy (MBCT) in Remitted Depressed Participants
Objectives: A combination of negatively biased information processing and a reduced ability to experience positive emotions can persist into remission from major depression (rMDD). Studies have shown that mindfulness-based cognitive therapy (MBCT) can increase self-reported positive emotions in rMDD participants; similar changes using neuropsychological tasks have not been shown. In this study, we investigated neuropsychological change in emotional processing following MBCT in rMDD participants. Methods: Seventy-three rMDD participants, 40 of whom received MBCT and 33 of whom continued with treatment as usual (TAU), and 42 never depressed participants took part; neither the TAU nor never depressed participants received MBCT. All were assessed at baseline and immediately following MBCT or after an 8-week gap for those without active intervention. Participants completed emotion evaluation and face emotion recognition tasks with self-report measures (mood, mindfulness) at each session. Results: Results showed an MBCT-specific shift in ratings from less negative to more positive emotion evaluations, which correlated with mindfulness practice and self-report mindfulness change. Both the MBCT and TAU groups showed a small increase in overall face emotion recognition accuracy compared with no change in never depressed participants. Conclusions: These findings support a specific role for MBCT in encouraging more positive evaluations of life situations in those with previous depression rather than influencing lower-level processing of emotions. Results should be interpreted cautiously given that this was a non-randomised, preference choice trial. Trial Registration: NCT0222604
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