5,905 research outputs found
Feature selectivity can explain mismatch signals in mouse visual cortex
Summary
Sensory experience often depends on one’s own actions, including self-motion. Theories of predictive coding postulate that actions are regulated by calculating prediction error, which is the difference between sensory experience and expectation based on self-generated actions. Signals consistent with prediction error have been reported in the mouse visual cortex (V1) when visual flow coupled to running was unexpectedly stopped. Here, we show that such signals can be elicited by visual stimuli uncoupled to an animal running. We record V1 neurons while presenting drifting gratings that unexpectedly stop. We find strong responses to visual perturbations, which are enhanced during running. Perturbation responses are strongest in the preferred orientation of individual neurons, and perturbation-responsive neurons are more likely to prefer slow visual speeds. Our results indicate that prediction error signals can be explained by the convergence of known motor and sensory signals, providing a purely sensory and motor explanation for purported mismatch signals
Study protocol: Delayed intervention randomised controlled trial within the Medical Research Council (MRC) Framework to assess the effectiveness of a new palliative care service
Background: Palliative care has been proposed to help meet the needs of patients who suffer
progressive non-cancer conditions but there have been few evaluations of service development
initiatives. We report here a novel protocol for the evaluation of a new palliative care service in
this context.
Methods/Design: Using the MRC Framework for the Evaluation of Complex Interventions we
modelled a new palliative care and neurology service for patients severely affected by Multiple
Sclerosis (MS). We conducted qualitative interviews with patients, families and staff, plus a
literature review to model and pilot the service. Then we designed a delayed intervention
randomised controlled trial to test its effectiveness as part of phase II of the MRC framework.
Inclusion criteria for the trial were patients identified by referring clinicians as having unresolved
symptoms or psychological concerns. Referrers were advised to use a score of greater than 8 on
the Expanded Disability Scale was a benchmark. Consenting patients newly referred to the new
service were randomised to either receive the palliative care service immediately (fast-track) or
after a 12-week wait (standard best practice). Face to face interviews were conducted at baseline
(before intervention), and at 4–6, 10–12 (before intervention for the standard-practice group), 16–
18 and 22–24 weeks with patients and their carers using standard questionnaires to assess
symptoms, palliative care outcomes, function, service use and open comments. Ethics committee
approval was granted separately for the qualitative phase and then for the trial.
Discussion: We publish the protocol trial here, to allow methods to be reviewed in advance of
publication of the results. The MRC Framework for the Evaluation of Complex Interventions was
helpful in both the design of the service, methods for evaluation in convincing staff and the ethics
committee to accept the trial. The research will provide valuable information on the effects of
palliative care among non-cancer patients and a method to evaluate palliative care in this context
Wiener Reconstruction of Large-Scale Structure from Peculiar Velocities
We present an alternative, Bayesian method for large-scale reconstruction
from observed peculiar velocity data. The method stresses a rigorous treatment
of the random errors and it allows extrapolation into poorly sampled regions in
real space or in k-space. A likelihood analysis is used to determine the
fluctuation power spectrum, followed by a Wiener Filter (WF) analysis to obtain
the minimum-variance mean fields of velocity and mass density. Constrained
Realizations (CR) are then used to sample the statistical scatter about the WF
mean field. The WF/CR method is applied as a demonstration to the Mark III data
with 1200 km/s, 900 km/s, and 500 km/s resolutions. The main reconstructed
structures are consistent with those extracted by the POTENT method. A
comparison with the structures in the distribution of IRAS 1.2Jy galaxies
yields a general agreement. The reconstructed velocity field is decomposed into
its divergent and tidal components relative to a cube of +/-8000 km/s centered
on the Local Group. The divergent component is very similar to the velocity
field predicted from the distribution of IRAS galaxies. The tidal component is
dominated by a bulk flow of 194 +/- 32 km/s towards the general direction of
the Shapley concentration, and it also indicates a significant quadrupole.Comment: 28 pages and 8 GIF figures, Latex (aasms4.sty), submitted to ApJ.
Postscript version of the figures can be obtained by anonymous ftp from:
ftp://alf.huji.ac.il/pub/saleem
An Effective Noise Adaptive Median Filter for Removing High Density Impulse Noises in Color Images
Images are normally degraded by some form of impulse noises during the acquisition, transmission and storage in the physical media. Most of the real time applications usually require bright and clear images, hence distorted or degraded images need to be processed to enhance easy identification of image details and further works on the image. In this paper we have analyzed and tested the number of existing median filtering algorithms and their limitations. As a result we have proposed a new effective noise adaptive median filtering algorithm, which removes the impulse noises in the color images while preserving the image details and enhancing the image quality. The proposed method is a spatial domain approach and uses the 3×3 overlapping window to filter the signal based on the correct selection of neighborhood values to obtain the effective median per window. The performance of the proposed effective median filter has been evaluated using MATLAB, simulations on a both gray scale and color images that have been subjected to high density of corruption up to 90% with impulse noises. The results expose the effectiveness of our proposed algorithm when compared with the quantitative image metrics such as PSNR, MSE, RMSE, IEF, Time and SSIM of existing standard and adaptive median filtering algorithms
Determinación por espectrofotometrÃa de la niclosamida a través de formulaciones base de Schiff en preparaciones farmacéuticas y veterinarias
Introduction: Niclosamide(NICS) its chemical name 5-chloro-N-(2- chloro-4-nitrophenyl)-2-hydroxybenz-amide]is the only commercially existing molluscicide optional by the WHO for large extent use in schistosomiasis be in charge of programs . NICS and its two new synthesized derivatives constructed to float on the water surface were able to kill cercariae, also obsessed promising activity in vitro nearby to an apicomplexan parasite Toxoplasma (4). Few spectrophotometric methods have been reported for the estimation of NICS as pure and in formulations, approximately these methods depend on reduction of nitro group (almost with zinc powder in acidic medium) followed by reaction with different reagents. The method based on reduction of nitro group of NICS then reaction of reduced-NICS with para- N,N dimethylaminobenzaldehyde in non-aqueous medium (methanol) to form a colored product that has been proved successfully for the estimation of NICS in pharmaceutical and veterinary formulations Material and method :All reagents used are of analytical grade and are obtained from Fluka or Aldrich , NICS wassupplied from SIGMA companies. Methanolic solution of para- N,N- dimethylanimobenzaldehyde (Fluka)3%, weighing 3 g and dissolved in 100 ml methanol in a volumetric flask. All other reagents were prepared bydissolving the propriety weight in perfect solvent. A volume in the range of 0.1 to 1.7 ml of 100 µg.ml-1RNICS solution was transferred to 10 ml calibrated flasks.2ml of PNNDMABA (3.0 %) was added, and the volume was made up to 10 ml by adding methanol. The yellow Schiff ’s base was measured at 454 nm versus a blank solution. Results and Discussion:The optimum pH for reaction of NICS with para-N, N-dimethylanimobenzaldehyde equal to 3 which resulted by mixing the components of the reaction. The absorbance increase with increasing reagent concentration (para-N,N- dimethylanimobenzaldehyde) and reached maximum on adding volume of 2.0 ml of (3%), which also gives the highest value of determination coefficient (R2).The experimental data indicated that methanol was the optimum solvent used in dilution according to high intensity of Schiff ’s base and the good stability. The formation of the yellow Schiff ’s base being complete after mixing the components of reaction and the absorbance remained constant for at least 2 hours. Conclusion: Accurate and sensitive spectrophotometric method was described for the estimation of NICS. The present method has been successfully applied for the estimation of NICS in pharmaceutical and veterinary preparations
Development of coordinated research efforts
The experience of ICRISAT with the use of Vertisols in semi-arid India indicates that the key to drastically improved productivity of Vertisols is the effective control of surface soil water which then enables rational use of the land for food and feed production. ILCA, therefore, developed and tested on-station and on-farm research in various highland Vertisol areas an animal-drawn implement for broadbed and furrow construction which was to combine technical efficiency of surface drainage construction with economic viability. Substantial increments in grain and biomass outputs due to enhanced surface drainage were recorded along with convincing economic returns to the farm in the application of this technology. In this chapter, history, objectives, rational, strategies, target areas and structure and organisation of the Vertisol project are presented; and the tasks of the advisory and technical committees, division the tasks of the advisory and technical committees, division of responsibilities between participating institutions, terms of reference for the technical committee, project phases and funding, and assistance by ICRISAt and IBSRAM are discussed
Report of the SocMon capacity development workshop for the Bay of Bengal Large Marine Ecosystem countries in South Asia, Vidathaltivu, Northern Province, Sri Lanka, 3-11 March, 2015
This Socioeconomic Monitoring (SocMon) training workshop was coordinated by the Small Fisher Federation of Lanka (SFFL). Planned outputs included: participants from Mannar trained in SocMon methodologies; draft SocMon reports fro Vidathaltivu; a workplan for Mannar; a communication strategy for Vidathaltivu/ Mannar; and key inputs to a regional SocMon strateg
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