Experimental measurement and theoretical modeling of microwave scattering and the structure of the sea surface influencing radar observations from space

The electromagnetic bias is an error present in radar altimetry of the ocean due to the non-uniform reflection from wave troughs and crests. A study of the electromagnetic bias became necessary to permit error reduction in mean sea level measurements of satellite radar altimeters. Satellite radar altimeters have been used to find the upper and lower bounds for the electromagnetic bias. This report will present a theory using physical optics scattering and an empirical model of the short wave modulation to predict the electromagnetic bias. The predicted electromagnetic bias will be compared to measurements at C and Ku bands

FAMILY SCAPEGOATING AND ADOLESCENT DEVELOPMENT

The clinical literature on families refers to the scapegoating of children by parents as a serious problem in certain dysfunctional families. This study explores scapegoating as a more general phenomenon that occurs in normal (i.e., non-clinical) families as well. The study utilized self-reports of 403 adolescents to assess the frequency and distribution of scapegoating in normal families and what adolescent difficulties are associated with family scapegoating. Most adolescent respondents reported experiencing family scapegoating. The pattern of family scapegoating self-reports varied more with the type of family conflict scapegoated than with the family member doing the scapegoating. Reports of family scapegoating were related to adjustment problems reported by the adolescent respondents. Also, there were less significant relationships between some forms of scapegoating and low self-esteem, delinquency and peer delinquency. Theoretical and clinical implications of the results were noted, as well as suggestions for future research

Polarisation structuring of broadband light

Spatial structuring of the intensity, phase and polarisation of light is useful in a wide variety of modern applications, from microscopy to optical communications. This shaping is most commonly achieved using liquid crystal spatial light modulators (LC-SLMs). However, the inherent chromatic dispersion of LC-SLMs when used as diffractive elements presents a challenge to the extension of such techniques from monochromatic to broadband light. In this work we demonstrate a method of generating broadband vector beams with dynamically tunable intensity, phase and polarisation over a bandwidth of 100 nm. We use our system to generate radially and azimuthally polarised vector vortex beams carrying orbital angular momentum, and beams whose polarisation states span the majority of the Poincaré sphere. We characterise these broadband vector beams using spatially and spectrally resolved Stokes measurements, and detail the technical and fundamental limitations of our technique, including beam generation fidelity and efficiency. The broadband vector beam shaper that we demonstrate here may find use in applications such as ultrafast beam shaping and white light microscopy

Polarisation structuring of broadband light

Spatial structuring of the intensity, phase and polarisation of light is useful in a wide variety of modern applications, from microscopy to optical communications. This shaping is most commonly achieved using liquid crystal spatial light modulators (LC-SLMs). However, the inherent chromatic dispersion of LC-SLMs when used as diffractive elements presents a challenge to the extension of such techniques from monochromatic to broadband light. In this work we demonstrate a method of generating broadband vector beams with dynamically tunable intensity, phase and polarisation over a bandwidth of 100 nm. We use our system to generate radially and azimuthally polarised vector vortex beams carrying orbital angular momentum, and beams whose polarisation states span the majority of the Poincaré sphere. We characterise these broadband vector beams using spatially and spectrally resolved Stokes measurements, and detail the technical and fundamental limitations of our technique, including beam generation fidelity and efficiency. The broadband vector beam shaper that we demonstrate here may find use in applications such as ultrafast beam shaping and white light microscopy

Nanoarrays for the generation of complex optical wave-forms

Light beams with unusual forms of wavefront offer a host of useful features to extend the repertoire of those developing new optical techniques. Complex, non-uniform wavefront structures offer a wide range of optomechanical applications, from microparticle rotation, traction and sorting, through to contactless microfluidic motors. Beams combining transverse nodal structures with orbital angular momentum, or vector beams with novel polarization profiles, also present new opportunities for imaging and the optical transmission of information, including quantum entanglement effects. Whilst there are numerous well-proven methods for generating light with complex wave-forms, most current methods work on the basis of modifying a conventional Hermite-Gaussian beam, by passage through suitably tailored optical elements. It has generally been considered impossible to directly generate wave-front structured beams either by spontaneous or stimulated emission from individual atoms, ions or molecules. However, newly emerged principles have shown that emitter arrays, cast in an appropriately specified geometry, can overcome the obstacles: one possibility is a construct based on the electronic excitation of nanofabricated circular arrays. Recent experimental work has extended this concept to a phase-imprinted ring of apertures holographically encoded in a diffractive mask, generated by a programmed spatial light modulator. These latest advances are potentially paving the way for creating new sources of structured light

Response to Crocetti et al.

No abstract available

Some Blood Parasite and Disease Antibody Findings in Wild Rio Grande Turkeys Stocked in Iowa

Thirty-nine wild Rio Grande turkeys (Meleagris gallopavo intermedia), live-trapped near Sonora, Texas, were tested for various blood parasites and disease antibodies before being released in the Yellow River State Forest in Allamakee County, Iowa, in the fall and winter of 1960-61. Haemoproteus meleagridis was found in 79% of the 39 turkeys· Salmonella pullorum in 15%; and chicken embryo lethal orphan virus (CELO) antibodies in 1 of 9 birds tested for evidence of that disease. Ornithosis was found in one pooled sample of serum that involved 4 birds but it was absent in 15 birds. No evidence was detected for Salmonella typhimurium, Leucocytozoon, Trypanosoma, Plasmodium, Mycoplasma, Newcastle disease virus or western equine viral encephalmoyelitis

Why They Come, Why They Go, and Why They Stay: Factors Affecting Volunteerism in 4-H Programs

The 4-H program depends on the work of thousands of adult volunteers. It seems prudent to understand more about the factors involved in an adult becoming a leader, factors contributing to the leader having a positive experience, and, in particular, the factors causing the leader to end his or her role. In order to better understand the experience of 4-H leaders and the factors contributing to their success, an exit survey was conducted with individuals who had terminated their leadership role. Key reasons for volunteering and leaving are identified

Alfalfa : An Economic Alternative to Corn?

Production costs and returns of alfalfa for different levels of management and at different prices are compared to shelled corn and corn silage, the major crops grown on the Belle Fourche Irrigation District