Field-induced Orbital Patterns in Ferromagnetic Layered Ruthenates

We study the evolution of orbital patterns in ferromagnetic layered ruthenates due to the competition of Coulomb interactions, compressive c axis and orthorhombic distortions in the presence of a polarizing orbital field coupled to the angular momentum. By means of the exact diagonalization on a 2x2 cluster and a cluster embedded analysis where inter-plaquette interaction is treated on mean field level, we determine the ground-state phase diagram. Specifically, we demonstrate that, via the activation of two or three of t_2g local orbital configurations, an external field applied along different symmetry directions can lead to inequivalent orbital correlated states. Starting from an antiferro-orbital pattern, for the easy axis case an orbital ordered phase is induced, having strong next nearest neighbors ferro-orbital correlations. Otherwise, a field applied along the hard axis leads a reduction of local orbital moment in a way to suppress the orbital order.Comment: 11 page

A Study Of Gender Differences With Respect To Internet Socialization Of Adolescents

This study investigates the differences between adolescent males and females in the perceived amount of knowledge regarding internet usage provided by various socialization agents (i.e. parents, school, media, and peers).  Further, it examines whether there is a significant difference in the amount of knowledge regarding internet usage provided by various socialization agents within gender.  The study takes a social learning perspective to examine the gender differences

Developing Social Responsibility: Impact of IS Service Learning Projects

Research has shown service learning to have an impact on the development of students\u27 professional knowledge and skills as well as their social awareness. However, there has been limited empirical research conducted regarding the benefits of service learning in the area of IS. Unlike service learning projects in other disciplines, where the service activity facilitates direct contact between the student and the individual being helped; IS service projects tend to focus on helping the organization better service the individual in need of assistance. Thus the student has an indirect, rather than direct, impact on the individuals being served. Given the indirect nature of these IS service projects, it is not clear if these projects generate any additional benefits over other pedagogical approaches and/or provide students an increased social awareness. Therefore the goal of this research project is to investigate whether IS service learning projects increase students\u27 sense of social responsibility

Socialization To The Internet: Who Is Teaching Our Children?

The introduction of technology into 21st century life has been fast and ubiquitous. The 2000 United States Census is filled with examples of increasing proportions of the American family who have access to computers and the internet. The issue of changes in our culture and the socialization of all parts of society bring logical questions about our children and technology. Where are they learning about the internet? Is the popular press correct in stating that there is a generational gap between parents and their children in socialization of technology? Where are they learning about the various uses of the Internet? This paper attempts to answer the question concerning who is teaching our children (about technology). Who is actually doing the socializing to technology

Determination of specific gravity of municipal solid waste

This investigation was conducted to evaluate experimental determination of specific gravity (Gs) of municipal solid waste (MSW). Water pycnometry, typically used for testing soils was adapted for testing MSW using a large flask with 2000 mL capacity and specimens with 100–350 g masses. Tests were conducted on manufactured waste samples prepared using US waste constituent components; fresh wastes obtained prior and subsequent to compaction at an MSW landfill; and wastes obtained from various depths at the same landfill. Factors that influence specific gravity were investigated including waste particle size, compaction, and combined decomposition and stress history. The measured average specific gravities were 1.377 and 1.530 for as-prepared/uncompacted and compacted manufactured wastes, respectively; 1.072 and 1.258 for uncompacted and compacted fresh wastes, respectively; and 2.201 for old wastes. The average organic content and degree of decomposition were 77.2% and 0%, respectively for fresh wastes and 22.8% and 88.3%, respectively for old wastes. The Gs increased with decreasing particle size, compaction, and increasing waste age. For fresh wastes, reductions in particle size and compaction caused occluded intraparticle pores to be exposed and waste particles to be deformed resulting in increases in specific gravity. For old wastes, the high Gs resulted from loss of biodegradable components that have low Gs as well as potential access to previously occluded pores and deformation of particles due to both degradation processes and applied mechanical stresses. The Gs was correlated to the degree of decomposition with a linear relationship. Unlike soils, the Gs for MSW was not unique, but varied in a landfill environment due both to physical/mechanical processes and biochemical processes. Specific gravity testing is recommended to be conducted not only using representative waste composition, but also using representative compaction, stress, and degradation states

Doping and dimensionality effects on the core-level spectra of layered ruthenates

Core-level spectra of the Mn-doped Sr3Ru2O7 and Srn+1RunO3n+1 (n = 1, 2 and 3) crystals are investigated with X-ray photoelectron spectroscopy. Doping of Mn to Sr3Ru2O7 considerably affects the distribution of core-level spectral weight. The satellite of Ru 3d core levels exhibits a substantial change with doping, indicating an enhanced electron localization across the doping- induced metal-insulator transition. However, the Ru 3p core levels remain identical with Mn-doping, thus showing no sign of doping-induced multiple Ru valences. In the Srn+1RunO3n+1 (n = 1, 2 and 3), the Ru 3d core-level spectra are similar, indicating that the chemical bonding environment around Ru ions remains the same for different layered compounds. Meanwhile the Sr 3d shallow core levels shift to higher binding energy with increasing n, suggesting their participation in Sr-O bonding with structural evolution.Comment: 6 pages with 6 figures, to be published in PR

Does degradation from selective logging and illegal activities differently impact forest resources? A case study in Ghana

Degradation, a reduction of the ecosystem’s capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions

Plaquette operators used in the rigorous study of ground-states of the Periodic Anderson Model in D=2D = 2 dimensions

The derivation procedure of exact ground-states for the periodic Anderson model (PAM) in restricted regions of the parameter space and D=2 dimensions using plaquette operators is presented in detail. Using this procedure, we are reporting for the first time exact ground-states for PAM in 2D and finite value of the interaction, whose presence do not require the next to nearest neighbor extension terms in the Hamiltonian. In order to do this, a completely new type of plaquette operator is introduced for PAM, based on which a new localized phase is deduced whose physical properties are analyzed in detail. The obtained results provide exact theoretical data which can be used for the understanding of system properties leading to metal-insulator transitions, strongly debated in recent publications in the frame of PAM. In the described case, the lost of the localization character is connected to the break-down of the long-range density-density correlations rather than Kondo physics.Comment: 34 pages, 5 figure

Reproductive Versus Floral Isolation Among Morphologically Similar Serapias L. Species (Orchidaceae)

Flowers of the Mediterranean orchid genus Serapias L. form small, dark tubes that vary among taxa in diameter and depth. Visiting insects use the floral tube as shelter and act as pollinators if they touch the sticky viscidium at the rear of the tube and remove the pollinarium. It has been assumed that floral tube size and shape limit access to the flowers and thus may act as a barrier to gene flow between different Serapias species. Here we investigated floral characters and nuclear microsatellite markers in populations belonging to three morphologically similar Serapias species to test whether these species show evidence for floral or reproductive isolation. We found strong overlap of floral traits between two species, suggesting that floral isolation is nonexistent between them. Microsatellite markers applied to the same populations were highly polymorphic and revealed clear genetic differentiation among all three species. These results suggest that reproductive isolation exists, despite the lack of floral isolation between two of the species. In contrast to morphological characters, diagnostic microsatellite alleles were found for all Serapias species. The microsatellite markers could thus provide a useful tool to identify Serapias species and further investigate evolutionary relationships in this fascinating orchid lineag