Next generation high density three-dimensional magnetic recording systems

This work is the first work using patterned soft underlayers in multilevel three-dimensional vertical magnetic data storage systems. The motivation stems from an exponentially growing information stockpile, and a corresponding need for more efficient storage devices with higher density. The world information stockpile currently exceeds 150EB (ExaByte=1x1018Bytes); most of which is in analog form. Among the storage technologies (semiconductor, optical and magnetic), magnetic hard disk drives are posed to occupy a big role in personal, network as well as corporate storage. However; this mode suffers from a limit known as the Superparamagnetic limit; which limits achievable areal density due to fundamental quantum mechanical stability requirements. There are many viable techniques considered to defer superparamagnetism into the 100's of Gbit/in2 such as: patterned media, Heat-Assisted Magnetic Recording (HAMR), Self Organized Magnetic Arrays (SOMA), antiferromagnetically coupled structures (AFC), and perpendicular magnetic recording. Nonetheless, these techniques utilize a single magnetic layer; and can thusly be viewed as two-dimensional in nature. In this work a novel three-dimensional vertical magnetic recording approach is proposed. This approach utilizes the entire thickness of a magnetic multilayer structure to store information; with potential areal density well into the Tbit/in2 regime. ^ There are several possible implementations for 3D magnetic recording; each presenting its own set of requirements, merits and challenges. The issues and considerations pertaining to the development of such systems will be examined, and analyzed using empirical and numerical analysis techniques. Two novel key approaches are proposed and developed: (1) Patterned soft underlayer (SUL) which allows for enhanced recording of thicker media, (2) A combinatorial approach for 3D media development that facilitates concurrent investigation of various film parameters on a predefined performance metric. A case study is presented using combinatorial overcoats of Tantalum and Zirconium Oxides for corrosion protection in magnetic media. ^ Feasibility of 3D recording is demonstrated, and an emphasis on 3D media development is emphasized as a key prerequisite. Patterned SUL shows significant enhancement over conventional "un-patterned" SUL, and shows that geometry can be used as a design tool to achieve favorable field distribution where magnetic storage and magnetic phenomena are involved. ^

Rio and the Reds: The Comando Vermelho, Organized Crime and Brazil’s Economic Ascent [Student’s Paper Series]

Brazil’s growing status as a potential world power cannot obscure the characteristics of its other reality: that of a country with vast inequalities and high crime rates. The Comando Vermelho, the most prominent organized crime syndicate in Rio de Janeiro, besieges the beauty and charm that attracts tourists to this city. The CV arose not only as a product of the political dictatorship of the seventies, but also of the disenfranchised urban poor crammed into Rio’s favela slums. Today, the CV presents a powerful challenge to the State’s control of parts of Rio territory. As Brazil’s soft power projection grows, it is seriously challenged by its capacity to eliminate organized crime. Economic growth is not sufficient to destroy a deeply embedded organization like the CV. In fact, Brazil’s success may yet further retrench the CV’s activities. Culpability for organized crime cannot be merely limited to the gangs, but must also be shared among the willing consumers, among whom can be found educated and elite members of society, as well as the impoverished and desperate. The Brazilian government needs a top-down response addressing the schism between rich and poor. However, Brazil’s citizens must also take responsibility and forge a bottom-up response to the drug- and corruption-riddled elements of its most respected members of society. Brazil must target reform across public health, housing, education and above all, law enforcement. Without such changes, Brazil will remain a two-track democracy. Rio’s wealthy will still be able to revel in the city’s beauty albeit from behind armored cars and fortified mansions, while the city’s poor will yield – either as victims or perpetrators – to the desperate measures of organized crime.

The effects of cross -age peer tutoring on writing and reading comprehension skills and attitudes and self -perceptions as writers of third and fourth grade students

The purpose of this study was to investigate the effects of cross-age peer writing response groups on the writing and reading achievement of third and fourth grade students. Students' attitudes about writing and their perceptions of themselves as writers were also measured at the end of the study. ^ One hundred and twenty-two third and fourth grade students enrolled in a public school in a middle-class, multi-cultural neighborhood participated in the study. Four existing classes of students were randomly assigned to either the experimental condition (EC) or the control condition (CC). Both groups were pretested and posttested for writing and reading achievement. The intervention, cross-age peer writing groups, met for eleven weeks. ^ Three hypotheses were examined in this study: (a) writing improvement score, (b) reading comprehension improvement score, and (c) students' attitudes toward writing and their perception of themselves as writers based on the five scales measured on the Writer Self-Perception Scale. ^ ANOVAs were done on the pretests and posttests for writing and the Stanford Achievement Test reading comprehension subtest scores for the year of the study and the previous year. ANOVAs were also done for the five areas of the Writer Self-Perception Scale. Cross-tabulations were also used to compare improvement level verses treatment group, and grade level. ^ Analysis of the data revealed that there was no evidence that the tutoring (EC) groups made more progress than the non-tutoring (CC) groups in writing and reading. There was evidence of growth in writing, especially by the fourth graders. Most importantly, the fourth grade tutors, the experimental group, had the most positive feelings about writing and themselves as writers. ^

The effect of cross -age tutoring routines on the tutor's perception of self as reader

Perception of self as a non-reader has been identified as one of the factors why poor readers disengage from the reading process (Strang, 1967; Rosow, 1992), thus impeding progress. Perception and informational processes influence judgments of personal efficacy (Bandura, 1997). The student's sense of reading efficacy that influence effort expenditure and ultimately achievement, is often overlooked (Athey, 1985; Pajares, 1996). Academic routines within educational programs are implemented without adequate information on whether routines promote or impede efficacy growth. Cross-age tutoring, a process known to improve participants' academic achievement, motivation, and provide opportunities for authentic reading practice, has been successfully incorporated into reading instruction designs (Allen, 1976; Cohen, Kulik & Kulik, 1982; Labbo & Teale, 1990; Riessman, 1993). This study investigated the impact teacher-designed routines within a cross-age tutoring model, have on the tutor's sense of reading self-efficacy. ^ The Reader Self-Perception Scale (Henk & Melnick, 1992) was administered, pre- and post-treatment, to 118 fifth grade students. Preceding the initial survey administration intact classes were randomly assigned to 1 of 3 commonly utilized cross-age tutoring routines or designated as the non-treatment population. The data derived from the Reader Self-Perception Scale was analyzed using an analysis of covariance (ANCOVA). Results indicated that participation as a cross-age tutor does not significantly increase the tutor's perception of self as reader in 1 or more of the 4 modes of information influencing self-efficacy as compared to the non-treatment group. ^ The results of this study suggests that although a weekly tutoring session that delivers educationally credible routines impacts achievement and motivation, efficacy effect was not evident. Possible explanation and recommendations for future studies are proposed. ^