Assessment of water pollution by airborne measurement of chlorophyll

Remote measurement of chlorophyll concentrations to determine extent of water pollution is discussed. Construction and operation of radiometer to provide measurement capability are explained. Diagram of equipment is provided

The design of linear multivariable control systems using modern control theory /with applications to coupled core reactor control/

Linear multivariable control system design using modern control theory, and application to coupled core reactor contro

Local Ferroelectricity in SrTiO_3 Thin Films

The temperature-dependent polarization of SrTiO_3 thin films is investigated using confocal scanning optical microscopy. A homogeneous out-of-plane and inhomogeneous in-plane ferroelectric phase are identified from images of the linear electrooptic response. Both hysteretic and non-hysteretic behavior are observed under a dc bias field. Unlike classical transitions in bulk ferroelectrics, local ferroelectricity is observed at temperatures far above the dielectric permittivity maximum. The results demonstrate the utility of local probe experiments in understanding inhomogeneous ferroelectrics.Comment: 8 pages, 3 figures, accepted for publication in PR

COMPARISON OF RUNOFF AND EROSION IN PRAIRIE, PASTURE, AND CULTIVATED LAND

Soil erosion resulting from runoff water has come to be recognized as a national menace. The determination and evaluation of all factors influencing runoff and erosion are studies of fundamental importance, especially insofar as they may be made to yield information upon methods of control over this insidious tendency of washing away the land. Fully 75 per cent of the crop-producing and grazing areas of the United States is sloping enough to set in motion, moderately or violently, these wasteful processes of accelerated soil-removal and excessive runoff. That 35 million acres of formerly cultivated land have been essentially ruined by erosion and that an additional area of about 125 million acres, still largely in cultivation, have lost all or most of the topsoil, with another 100 million acres of crop-land heading in this direction, should be sufficient evidence that the problem is one of profound economic importance. Especially must this be considered true since the wastage is now proceeding faster than ever, owing to the fact that considerable time was required to strip off the more absorptive surface-layer from millions of acres, and to the further fact that the subsoil is generally more erosive than the soil. The cost runs into hundreds of millions of dollars annually, in the way of direct depreciation and essential destruction of fields and pastures, the silting of reservoirs, stream-channels and ditches, damage to highway and railway fills and embankments, choking of culverts, covering of valuable valley-lands with relatively unproductive erosional debris, and pollution of former clear-water streams with excessive loads of silt and clay washed out of the hills (Bennett, \u2734). Much experimentation has been carried on and numerous papers have been written on the effects of a forest cover in promoting absorption of rainfall and controlling erosion. But a study of grass as a stabilizer of lands and a means of increasing absorption and diminishing runoff has just begun. It has resulted from the present physical crisis in land use within the United States and especially in the west. This crisis is a consequence of the period of exploitation resulting from the rapid occupation of the whole country by a civilized people. The story of American agriculture has been one of breaking new soil, farming it hard, and then, when yields began to fall off, moving west to repeat the cycle. The time has gone, however, when worn out lands can be abandoned for virgin soils, with their stored fertility, and undepleted ranges lying to the west. These changes have occurred rapidly. As stated by Lowdermilk (\u2735a ): Soils which had been thoroughly protected through thousands of years of time by unbroken mantles of vegetation, and, for this reason, had weathered to fine textures with high organic contents so favorable to \u27mellowness\u27 and good fertility, were suddenly exposed to the dash of torrential rains characterizing the climate of extensive regions. . .. Topsoils have been literally washed away, leaving raw, comparatively unproductive, unabsorptive, intractible subsoil exposed at the surface ..... of the greater part of the crop and grazing areas of the West. The natural cover of prairie vegetation has nearly all been removed by breaking, or sorely depleted by continued overgrazing. This effective preventive of erosion has been replaced by poorly sodded pastures and lands covered only temporarily with crops. Overgrazing on the one hand and cultural practices on the other have exposed much of the surface of both to the destructive action of rain and runoff waters. With a widespread erosion control campaign going on throughout the United States with the object of the best type of soil conservation, it is peculiarly desirable to take full account of the influence of plant cover. Moreover, in examining the effects of disturbances wrought by man, his implements and machines, and his domestic animals, it is desirable to begin investigations with undisturbed natural condition of the land. Fortunately many limited areas of natural grassland, especially prairies kept for the production of hay, remain to facilitate such comparative studies

A Study of Incarcerated Youth: The Effect of Student Interest on Reading Comprehension and Engagement

Motivating adolescents to read can be a challenge, but motivating incarcerated adolescents to read may be even more of a challenge. Developing readers in residential facilities are often overlooked by traditional classroom teachers, but much can be learned from incarcerated youth and their motivation and engagement. Unfortunately, there is a shortage of research on effective instructional reading practices that motivate and engage incarcerated youth. The existing research primarily examines the impact of literacy on recidivism instead of strategies for motivating and engaging students who are incarcerated. Numerous studies exist that focus on motivation and engagement of reading in traditional classrooms, but these studies are limited when focused on students from the classrooms in juvenile residential centers. This qualitative study examines the influence of high-interest materials on the comprehension of incarcerated youth and the effect of student dispositions on reading engagement. While there was no obvious correlation between high-interest materials and student comprehension scores, the results of the study suggest that mentor/student rapport, vulnerability, high-interest materials, self-efficacy, and value placed on reading all factor into student motivation and engagement