A Preliminary Report of a New Departure in Mental Measurements and Some of its Practical Applications

The field of mental measurements has been dominated by a theory sterile in its contributions to systematized psychology. Moreover, most traditional types of objective examinations do not adequately test anything more than amount of discrete information compiled. This technique goes beyond mere information, getting into the subtler intricacies of human thought and the functional aspects of intelligence. A definite theoretical psychological basis underlies this approach, and it is believed that important contributions to general theory can result from this type of experimentation. Future use in the individualization of instruction at the rate and level of the student\u27s ability is described

A New Departure in Mental Measurements

At the 1933 meeting of this group we presented a brief discussion of a proposed new departure in the field of mental measurements. At that time we pointed out the rather widespread dissatisfaction with current types of mental and educational tests. The first criticism was based upon the lack of agreement of test theory with the best psychological knowledge. Another criticism dealt with the fact that tests (especially educational tests) tended to emphasize the measurement of mere possession of knowledge rather than the functional significance of such knowledge. Finally, it was noted that the primary concern of the psychologist in test building was to study the behavior of minds, and that to expect to study such behavior through an instrument not constructed in the light of our best knowledge of how the mind works was, in itself, an invalid procedure

A Study of Individualized Instruction at the College Level

With a philosophy that makes paramount the greatest possible growth for each individual student as the background, the Department of French at the University of Iowa has conceived and put into operation a plan of individualized instruction. This plan, in effect since September, 1933, marks the latest development of a comprehensive experimental program which has had continuous growth during the past ten years

The Stable Roommates problem with short lists

We consider two variants of the classical Stable Roommates problem with Incomplete (but strictly ordered) preference lists SRI that are degree constrained, i.e., preference lists are of bounded length. The first variant, EGAL d-SRI, involves finding an egalitarian stable matching in solvable instances of SRI with preference lists of length at most d. We show that this problem is NP-hard even if d=3. On the positive side we give a (2d+3)/7-approximation algorithm for d={3,4,5} which improves on the known bound of 2 for the unbounded preference list case. In the second variant of SRI, called d-SRTI, preference lists can include ties and are of length at most d. We show that the problem of deciding whether an instance of d-SRTI admits a stable matching is NP-complete even if d=3. We also consider the "most stable" version of this problem and prove a strong inapproximability bound for the d=3 case. However for d=2 we show that the latter problem can be solved in polynomial time.Comment: short version appeared at SAGT 201

Structure determination of the reconstructed Au(110) surface

The LEED pattern of the Au(110) surface shows a (1 × 2) and also a (1× 3) superstructure. The (1 × 2) superstructure has been determined by comparison of LEED intensities with model calculations. The missing row model is the most probable model. A minimum of the averaged r-factor, , has been found for 15% contraction of the first layer spacing without atomic displacements in the second layer

Early-type galaxies in the Chandra COSMOS Survey

We study a sample of 69 X-ray detected Early Type Galaxies (ETGs), selected from the Chandra COSMOS survey, to explore the relation between the X-ray luminosity of hot gaseous halos (L_X, gas) and the integrated stellar luminosity (L_K) of the galaxies, in a range of redshift extending out to z=1.5. In the local universe a tight steep relationship has been stablished between these two quantities (L_X,gas~ L_K^4.5) suggesting the presence of largely virialized halos in X-ray luminous systems. We use well established relations from the study of local universe ETGs, together with the expected evolution of the X-ray emission, to subtract the contribution of low mass X-ray binary populations (LMXBs) from the X-ray luminosity of our sample. Our selection minimizes the presence of active galactic nuclei (AGN), yielding a sample representative of normal passive COSMOS ETGs; therefore the resulting luminosity should be representative of gaseous halos, although we cannot exclude other sources such as obscured AGN, or enhanced X-ray emission connected with embedded star formation in the higher z galaxies. We find that most of the galaxies with estimated L_X<10^42 erg/s and z<0.55 follow the L_X,gas- L_K relation of local universe ETGs. For these galaxies, the gravitational mass can be estimated with a certain degree of confidence from the local virial relation. However, the more luminous (10^42<L_X<10^43.5 erg/s) and distant galaxies present significantly larger scatter; these galaxies also tend to have younger stellar ages. The divergence from the local L_X,gas - L_K relation in these galaxies implies significantly enhanced X-ray emission, up to a factor of 100 larger than predicted from the local relation. We discuss the implications of this result for the presence of hidden AGN, and the evolution of hot halos, in the presence of nuclear and star formation feedback.Comment: 29 pages, 10 figures, accepted for publication on ApJ on May 27 201

Skeleton and fractal scaling in complex networks

We find that the fractal scaling in a class of scale-free networks originates from the underlying tree structure called skeleton, a special type of spanning tree based on the edge betweenness centrality. The fractal skeleton has the property of the critical branching tree. The original fractal networks are viewed as a fractal skeleton dressed with local shortcuts. An in-silico model with both the fractal scaling and the scale-invariance properties is also constructed. The framework of fractal networks is useful in understanding the utility and the redundancy in networked systems.Comment: 4 pages, 2 figures, final version published in PR