Colour Relations in Form

The orthodox monadic determination thesis holds that we represent colour relations by virtue of representing colours. Against this orthodoxy, I argue that it is possible to represent colour relations without representing any colours. I present a model of iconic perceptual content that allows for such primitive relational colour representation, and provide four empirical arguments in its support. I close by surveying alternative views of the relationship between monadic and relational colour representation

Blue cone monochromacy: causative mutations and associated phenotypes.

PurposeTo perform a phenotypic assessment of members of three British families with blue cone monochromatism (BCM), and to determine the underlying molecular genetic basis of disease.MethodsAffected members of three British families with BCM were examined clinically and underwent detailed electrophysiological and psychophysical testing. Blood samples were taken for DNA extraction. Molecular analysis involved the amplification of the coding regions of the long (L) and medium (M) wave cone opsin genes and the upstream locus control region (LCR) by polymerase chain reaction (PCR). Gene products were directly sequenced and analyzed.ResultsIn all three families, genetic analysis identified that the underlying cause of BCM involved an unequal crossover within the opsin gene array, with an inactivating mutation. Family 1 had a single 5'-L-M-3' hybrid gene, with an inactivating Cys203Arg (C203R) mutation. Family 3 had an array composed of a C203R inactivated 5'-L-M-3' hybrid gene followed by a second inactive gene. Families 1 and 3 had typical clinical, electrophysiological, and psychophysical findings consistent with stationary BCM. A novel mutation was detected in Family 2 that had a single hybrid gene lacking exon 2. This family presented clinical and psychophysical evidence of a slowly progressive phenotype.ConclusionsTwo of the BCM-causing family genotypes identified in this study comprised different hybrid genes, each of which contained the commonly described C203R inactivating mutation. The genotype in the family with evidence of a slowly progressive phenotype represents a novel BCM mutation. The deleted exon 2 in this family is not predicted to result in a shift in the reading frame, therefore we hypothesize that an abnormal opsin protein product may accumulate and lead to cone cell loss over time. This is the first report of slow progression associated with this class of mutation in the L or M opsin genes in BCM

Construction of an Instrumentation Kit for Identification and Control of DC Motors

This paper presents the development of an instrumentation kit of voltage and current measurement for identification of the dynamic model and control of direct current (DC) motors. In the methodology for the parameters identification is used the responses of input voltage and current, and angular velocity of the DC motor. The validation of the obtained dynamic model is done through the comparison of the simulated and experimental responses, and the application of a control system based on state feedback and complete eigenstructure assignment (tracking system). The responses are compared through the normalized root-mean-square error criterion

Virtual Prototyping, Identification and Control of a Twin Rotor with 3DOF

This paper presents a methodology for identification of the physical characteristics, generation of the mathematical model through virtual prototyping and control of the didactic plant of a twin rotor. In the identification of the physical characteristics, the centers of mass and moments of inertia of the twin rotor parts were identified separately, by means of an easel designed for such task. Still in the identification of the physical characteristics, the equation that relates the applied voltage in the direct current motor with the thrust force produced by the propellers was obtained. The mathematical model of the twin rotor was obtained by means of the identification of the physical characteristics allied to the virtual prototyping with the aid of ADAMS and SolidWorks software. The implemented control system uses state feedback and complete eigenstructure assignment. The ease and usefulness of the proposed methodology was presented through the plant instrumentation, simulation and control in MATLAB/Simulink environment

Control of a Modified Ball and Beam System Using Tracking System in Real Time with a DC Motor as an Actuator

This paper presents amodified ball and beam system, with the intention of realizing a test bed, to study new control techniques in real-time.The ball and beam system consists of a ball over a long beam where the control objective is to stabilizethe position of the ball on the beam by changing the angular position of the beam.In this paper, the ball of the conventional system is replaced by a cart with an embedded microcontroller, enabling the use of a linear encoder as position sensor and allowing to transmit the position via RF (Radio Frequency). The mathematical model of the ball and beam is obtained through the equations of Newton-Euler and the equations were linearized. The system is controlled using the hardware-in-the-loop technique with MATLAB/Simulink.It is applied a tracking control system with entire eigenstructure assignment to control the position of the cart. The actuator used is a DC motor, and a PID(proportional, integral and derivative) control is used to perform the angular position control of beam.The simulation results and the experimental results are compared to validate the mathematical model. The results obtained were satisfactory with adequate accuracy

Estimating individual cone fundamentals from their color-matching functions

Estimation of individual spectral cone fundamentals from color-matching functions is a classical and longstanding problem in color science. In this paper we propose a novel method to carry out this estimation based on a linear optimization technique, employing an assumption of a priori knowledge of the retinal absorptance functions. The result is an estimation of the combined lenticular and macular filtration for an individual, along with the nine coefficients in the linear combination that relates their color-matching functions to their estimated spectral-cone fundamentals. We test the method on the individual Stiles and Burch color-matching functions and derive cone-fundamental estimations for different viewing fields and matching experiment repetition. We obtain cone-fundamental estimations that are remarkably similar to those available in the literature. This suggests that the method yields results that are close to the true fundamentals

A new Mooney test

This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.3758/s13428-015-0666-0Since its introduction in 1957, the Mooney test has continued to see active use in studies of visual perception, in studies using brain imaging, and in clinical research. Mooney?s original version is of limited length, however, and was designed to be administered by time-consuming personal interview. We have developed a new, extended version of the Mooney test that is suitable for online testing and for use in a test?retest paradigm. The Mooney?Verhallen Test (MVT) comprises 144 trials, takes on average less than 10 min to complete, and has a Spearman?Brown-corrected test?retest reliability of ? = .89. We outline our methods for developing the stimuli and for selecting the final stimulus set, and we present the results from two rounds of testing on two independent samples of 374 participants and 505 participants, respectively. The test is freely available for scientific use.RJV is grateful for funding received from the Prins Bernhard Cultuurfonds, the Hendrik Muller Fonds, the Grindley Fund, and the Cambridge Philosophical Society

Retinal Ganglion Cells-Diversity of Cell Types and Clinical Relevance.

Retinal ganglion cells (RGCs) are the bridging neurons that connect the retinal input to the visual processing centres within the central nervous system. There is a remarkable diversity of RGCs and the various subtypes have unique morphological features, distinct functions, and characteristic pathways linking the inner retina to the relevant brain areas. A number of psychophysical and electrophysiological tests have been refined to investigate this large and varied population of RGCs. Technological advances, such as high-resolution optical coherence tomography imaging, have provided additional tools to define the pattern of RGC involvement and the chronological sequence of events in both inherited and acquired optic neuropathies. The mechanistic insights gained from these studies, in particular the selective vulnerability and relative resilience of particular RGC subtypes, are of fundamental importance as they are directly relevant to the development of targeted therapies for these invariably progressive blinding diseases. This review provides a comprehensive description of the various types of RGCs, the developments in proposed methods of classification, and the current gaps in our knowledge of how these RGCs are differentially affected depending on the underlying aetiology. The synthesis of the current body of knowledge on the diversity of RGCs and the pathways that are potentially amenable to therapeutic modulation will hopefully lead to much needed effective treatments for patients with optic neuropathies