Constancy Of Effects Research Articles

Functional and structural comparison of visual lateralization in birds - similar but still different.

Vertebrate brains display physiological and anatomical left-right differences, which are related to hemispheric dominances for specific functions. Functional lateralizations likely rely on structural left-right differences in intra- and interhemispheric connectivity patterns that develop in tight gene-environment interactions. The visual systems of chickens and pigeons show that asymmetrical light stimulation during ontogeny induces a dominance of the left hemisphere for visuomotor control that is paralleled by projection asymmetries within the ascending visual pathways. But structural asymmetries vary essentially between both species concerning the affected pathway (thalamo- vs. tectofugal system), constancy of effects (transient vs. permanent), and the hemisphere receiving stronger bilateral input (right vs. left). These discrepancies suggest that at least two aspects of visual processes are influenced by asymmetric light stimulation: (1) visuomotor dominance develops within the ontogenetically stronger stimulated hemisphere but not necessarily in the one receiving stronger bottom-up input. As a secondary consequence of asymmetrical light experience, lateralized top-down mechanisms play a critical role in the emergence of hemispheric dominance. (2) Ontogenetic light experiences may affect the dominant use of left- and right-hemispheric strategies. Evidences from social and spatial cognition tasks indicate that chickens rely more on a right-hemispheric global strategy whereas pigeons display a dominance of the left hemisphere. Thus, behavioral asymmetries are linked to a stronger bilateral input to the right hemisphere in chickens but to the left one in pigeons. The degree of bilateral visual input may determine the dominant visual processing strategy when redundant encoding is possible. This analysis supports that environmental stimulation affects the balance between hemispheric-specific processing by lateralized interactions of bottom-up and top-down systems.

Instrumental quantile regression inference for structural and treatment effect models

We introduce a class of instrumental quantile regression methods for heterogeneous treatment effect models and simultaneous equations models with nonadditive errors and offer computable methods for estimation and inference. These methods can be used to evaluate the impact of endogenous variables or treatments on the entire distribution of outcomes. We describe an estimator of the instrumental variable quantile regression process and the set of inference procedures derived from it. We focus our discussion of inference on tests of distributional equality, constancy of effects, conditional dominance, and exogeneity. We apply the procedures to characterize the returns to schooling in the U.S.

ETIOLOGICAL FACTORS IN PLACEBO EFFECT.

Never before has there been so much interest in the placebo effect. Despite a greatly increased amount of research, the etiology of the placebo effect is not yet understood. This paper critically evaluates recently advanced concepts concerning the placebo effect, including personality of the patient, anxiety, catharsis, suggestibility, psychiatric diagnosis, constancy of effect, and the physician's interest. The physician's interest can be direct or indirect. The concept of indirect interest is advanced as an important subtle mechanism that may parsimoniously explain many observations about placebos.

Stabilization of variable high voltage D.C.

An equipment has been developed to permit the use of the public supply mains for the measurement of leakage conductance of condensers to an accuracy of ± 1.5 × 10-12 mho over a voltage range of 0-5 kV. The devices incorporated reduce by the order of 600: 1 the galvanometer fluctuations due to displacement currents which arise from anomalous fluctuations of the supply voltage. For example, an effective constancy of 5 in 10-5 can be achieved with a supply which fluctuates by 3 per cent. Theoretical consideration of the contribution of the various circuit components indicates means of obtaining a still higher degree of suppression.