Showing papers by "Florida State University published in 2001"

Spintronics: a spin-based electronics vision for the future.

Abstract: This review describes a new paradigm of electronics based on the spin degree of freedom of the electron. Either adding the spin degree of freedom to conventional charge-based electronic devices or using the spin alone has the potential advantages of nonvolatility, increased data processing speed, decreased electric power consumption, and increased integration densities compared with conventional semiconductor devices. To successfully incorporate spins into existing semiconductor technology, one has to resolve technical issues such as efficient injection, transport, control and manipulation, and detection of spin polarization as well as spin-polarized currents. Recent advances in new materials engineering hold the promise of realizing spintronic devices in the near future. We review the current state of the spin-based devices, efforts in new materials fabrication, issues in spin transport, and optical spin manipulation.

Some New Thoughts on Conceptualizing Perceived Service Quality: A Hierarchical Approach:

Abstract: Through qualitative and empirical research, the authors find that the service quality construct conforms to the structure of a third-order factor model that ties service quality perceptions to distinct and actionable dimensions: outcome, interaction, and environmental quality. In turn, each has three subdimensions that define the basis of service quality perceptions. The authors further suggest that for each of these subdimensions to contribute to improved service quality perceptions, the quality received by consumers must be perceived to be reliable, responsive, and empathetic. The authors test and support this conceptualization across four service industries. They consider the research and managerial implications of the study and its limitations.

Thirty years of investigating the own-race bias in memory for faces: A meta-analytic review

Abstract: The current article reviews the own-race bias (ORB) phenomenon in memory for human faces, the finding that own-race faces are better remembered when compared with memory for faces of another, less familiar race. Data were analyzed from 39 research articles, involving 91 independent samples and nearly 5,000 participants. Measures of hit and false alarm rates, and aggregate measures of discriminatio n accuracy and response criterion were examined, including an analysis of 8 study moderators. Several theoretical relationships were also assessed (i.e., the influence of racial attitudes and interracial contact). Overall, results indicated a "mirror effect" pattern in which own-race faces yielded a higher proportion of hits and a lower proportion of false alarms compared with other-race faces. Consistent with this effect, a significant ORB was also found in aggregate measures of discriminatio n accuracy and response criterion. The influence of perceptual learning and differentiation processes in the ORB are discussed, in addition to the practical implications of this phenomenon. She based her identification on Smith's eyes, which she said were greenish-blue and upon his hands which she said were "light and slender" like the holdup man's. Mrs. McCormick testified that Smith's eyes were "different from most colored people ... bright and piercing." Smith's defense attorneys then attempted to parry the state's first thrust in the trial. Mrs. McCormick was handed a picture of a man she couldn't identify. It was a picture of David Charles, with shorter hair, taken while he was in Vietnam. Assistant defense attorney Kitchen asked Mrs. McCormick if she had ever made the statement that all Black people look alike. "Yes, I made that statement," Mrs. McCormick said, "and they do to a certain extent, but there's a difference here" (Lickson, 1974, p. 66). In 1971, five Black men, who became known as the "Quincy Five," were wrongfully indicted for the murder of Khomas Revels during a robbery in Tallahassee, Florida. Although no forensic evidence obtained from the crime scene was ever linked to the men, five White eyewitnesses positively identified them as among the perpetrators. In each of three trials the state argued, "What better evidence can there be than, 'I saw him,' from unprejudiced witnesses? This has been used since time immemorial. This is proof beyond a reasonable doubt. Five eyewitnesses!" (Lickson, 1974, p. 87). Despite the lack of physical evidence against these men, two of the defendants, Dave Roby Keaton and Johnny Frederick, were found guilty on the basis of eyewitness testimony and coerced confessions obtained by investigators . During the third trial involving David

Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze

Abstract: Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects. The haze particles consisted of several inorganic and carbonaceous species, including absorbing black carbon clusters, fly ash, and mineral dust. The most striking result was the large loading of aerosols over most of the South Asian region and the North Indian Ocean. The January to March 1999 visible optical depths were about 0.5 over most of the continent and reached values as large as 0.2 over the equatorial Indian ocean due to long-range transport. The aerosol layer extended as high as 3 km. Black carbon contributed about 14% to the fine particle mass and 11% to the visible optical depth. The single-scattering albedo estimated by several independent methods was consistently around 0.9 both inland and over the open ocean. Anthropogenic sources contributed as much as 80% (±10%) to the aerosol loading and the optical depth. The in situ data, which clearly support the existence of the first indirect effect (increased aerosol concentration producing more cloud drops with smaller effective radii), are used to develop a composite indirect effect scheme. The Indo-Asian aerosols impact the radiative forcing through a complex set of heating (positive forcing) and cooling (negative forcing) processes. Clouds and black carbon emerge as the major players. The dominant factor, however, is the large negative forcing (-20±4 W m^(−2)) at the surface and the comparably large atmospheric heating. Regionally, the absorbing haze decreased the surface solar radiation by an amount comparable to 50% of the total ocean heat flux and nearly doubled the lower tropospheric solar heating. We demonstrate with a general circulation model how this additional heating significantly perturbs the tropical rainfall patterns and the hydrological cycle with implications to global climate.

Functionalized Pentacene: Improved Electronic Properties from Control of Solid-State Order

Abstract: Molecular order has proven to be a significant factor in the performance of devices based on organic semiconductors. Recent studies involving solubilized versus unsubstituted thiophene oligomers have demonstrated that modifications which increase orbital overlap in the solid state can improve device performance by more than an order of magnitude. 1 Similar studies on pentacene, a compound which has already demonstrated remarkable potential for device applications, 2 have also focused on maximizing orbital overlap by inducing order in films. 3 However, these pentacene studies have thus far relied on substrate modification, rather than on pentacene functionalization, 4 to achieve the desired goals. We report here the preparation of two functionalized pentacene derivatives, and the effect of this functionalization on both the solid-state ordering and the electronic properties of the resulting crystals. Our goal for a functionalized pentacene was two-fold: First, the substituents should impart solubility to the acene, to simplify purification and processing. Second, the substituents should induce some capability for self-assembly of the aromatic moieties into ﷿-stacked arrays to enhance intermolecular orbital overlap. We anticipated that both of these goals could be accomplished by exploiting a rigid spacer to hold the necessarily bulky solubilizing groups well away from the aromatic core, allowing the closest possible contact between the aromatic rings. 5 Our initial targets were the bis(triisopropylsilylethynyl)pentacenes 1 and 2. Both of these compounds are easily prepared in near quantitative yield in a one-pot reaction from 6,13-pentacenequinone and 5,14pentacenequinone, respectively. 6

Does market orientation matter?: a test of the relationship between positional advantage and performance

Abstract: A recent series of articles in the Strategic Management Journal has discussed the potential value of an organization developing a market orientation in its quest to achieve success. We posit that market orientation can enhance success, but that its potential value should not be considered in isolation. Specifically, we draw on the resource-based view of the firm to suggest that four capabilities—market orientation, entrepreneurship, innovativeness, and organizational learning—each contribute to the creation of positional advantages for some firms. The data used are drawn from 181 large multinational corporations (MNC). The results indicate that positional advantages arising from the confluence of market orientation, entrepreneurship, innovativeness, and organizational learning have a positive effect on MNC performance (five-year average change in ROI, income, and stock price). Overall, the results support the contention that market orientation can enhance success, albeit within the context of other important phenomena. Copyright © 2001 John Wiley & Sons, Ltd.

Intensive Remedial Instruction for Children with Severe Reading Disabilities: Immediate and Long-term Outcomes From Two Instructional Approaches

Abstract: Sixty children with severe reading disabilities were randomly assigned to two instructional programs that incorporated principles of effective instruction but differed in depth and extent of instruction in phonemic awareness and phonemic decoding skills. All children received 67.5 hours of one-to-one instruction in two 50-minute sessions per day for 8 weeks. Both instructional programs produced very large improvements in generalized reading skills that were stable over a 2-year follow-up period. When compared to the growth in broad reading ability that the participants made during their previous 16 months in learning disabilities resource rooms, their growth during the intervention produced effect sizes of 4.4 for one of the interventions and 3.9 for the other. Although the children's average scores on reading accuracy and comprehension were in the average range at the end of the follow-up period, measures of reading rate showed continued severe impairment for most of the children. Within 1 year following the intervention, 40% of the children were found to be no longer in need of special education services. The two methods of instruction were not differentially effective for children who entered the study with different levels of phonological ability, and the best overall predictors of long-term growth were resource room teacher ratings of attention/behavior, general verbal ability, and prior levels of component reading skills.

Logistics Service Quality as a Segment-Customized Process

Abstract: Logistics excellence has become a powerful source of competitive differentiation within diverse marketing offerings of world-class firms. Although researchers have suggested that logistics competencies complement marketing efforts, empirical evidence is lacking on what logistics service quality means to customers and whether it has different meanings for separate customer segments. The authors present empirical support for nine related logistics service quality constructs; demonstrate their unidimensionality, validity, and reliability across four customer segments of a large logistics organization; and provide empirical support for a logistics service quality process. Although structural equation modeling offers support for the logistics service quality process across customer segments, the authors find that the relative parameter estimates differ for each segment, which suggests that firms ought to customize their logistics services by customer segments.

Suppression of hadrons with large transverse momentum in central Au + Au collisions at √sNN = 130 GeV

Abstract: Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 Gev/c < P-T < 5 GeV/c have been measured by the PHENIX experiment at RHIC in Au + Au collisions at rootS(NN) = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p + p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p + p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

The changing state of gentrification

Abstract: Gentrification has changed in ways that are related to larger economic and political restructuring. Among these changes is the return of heavy state intervention in the process. This paper explores heightened state involvement in gentrification by examining the process in three New York City neighbourhoods: Clinton, Long Island City, and DUMBO (Down Under the Manhattan Bridge Overpass). We argue that state intervention has returned for three key reasons. First, continued devolution of federal states has placed even more pressure on local states to actively pursue redevelopment and gentrification as ways of generating tax revenue. Second, the diffusion of gentrification into more remote portions of the urban landscape poses profit risks that are beyond the capacity of individual capitalists to manage. Third, the larger shift towards post–Keynesian governance has unhinged the state from the project of social reproduction and as such, measures to protect the working class are more easily contested.

Superconducting 2D System with Lifted Spin Degeneracy: Mixed Singlet-Triplet State

Abstract: Motivated by recent experimental findings, we have developed a theory of the superconducting state for 2D metals without inversion symmetry modeling the geometry of a surface superconducting layer in a field-effect transistor or near the boundary doped by adsorbed ions. In such systems the twofold spin degeneracy is lifted by spin-orbit interaction, and singlet and triplet pairings are mixed in the wave function of the Cooper pairs. As a result, spin magnetic susceptibility becomes anisotropic and Knight shift retains finite and rather high value at T = 0.

Kendrick mass defect spectrum: a compact visual analysis for ultrahigh-resolution broadband mass spectra.

Abstract: At currently achievable Fourier transform ion cyclotron resonance broadband mass spectrometry resolving power (m/Δm50% > 350 000 for 200 < m/z < 1000), it would be necessary to spread out a conventional mass spectrum over ∼200 m in order to provide visual resolution of the most closely resolved peaks. Fortunately, there are natural gaps in a typical mass spectrum, spaced 1 Da apart, because virtually no commonly encountered elemental compositions yield masses at those values. Thus, it is possible to break a broadband mass spectrum into 1-Da segments, rotate each segment by 90°, scale each segment according to its mass defect (i.e., difference between exact and nominal mass), and then compress the spacing between the segments to yield a compact display. For hydrocarbon systems, conversion from IUPAC mass to “Kendrick” mass (i.e., multiplying each mass by 14.00000/14.01565) further simplifies the display by rectilinearizing the peak patterns. The resulting display preserves not only the “coarse” spacings (e...

Customer Orientation: Effects on Customer Service Perceptions and Outcome Behaviors

Abstract: This study investigates the effect of being customer oriented on service performance perceptions and outcome behaviors. Specifically, the focus is on identifying the influence that being perceived ...

A History of Instructional Design and Technology: Part II: A History of Instructional Design

Abstract: This is the second of a two-part article that discusses the history of the field of instructional design and technology in the United States. The first part, which focused on the history of instructional media, appeared in the previous issue of this journal (volume 49, number 1). This part of the article focuses on the history of instructional design. Starting with a description of the efforts to develop training programs during World War II, and continuing on through the publication of some of the first instructional design models in the 1960s and 1970s, major events in the development of the instructional design process are described. Factors that have affected the field of instructional design over the last two decades, including increasing interest in cognitive psychology, microcomputers, performance technology, and constructivism, are also described.

Neutron Star Structure and the Neutron Radius of 208Pb

Abstract: We study relationships between the neutron-rich skin of a heavy nucleus and the properties of neutron-star crusts. Relativistic effective field theories with a thicker neutron skin in ${}^{208}\mathrm{Pb}$ have a larger electron fraction and a lower liquid-to-solid transition density for neutron-rich matter. These properties are determined by the density dependence of the symmetry energy which we vary by adding nonlinear couplings between isoscalar and isovector mesons. An accurate measurement of the neutron radius in ${}^{208}\mathrm{Pb}$---via parity violating electron scattering---may have important implications for the structure of the crust of neutron stars.

Neighborhood disadvantage, stress, and drug use among adults.

Abstract: This paper explores the relationships among neighborhood disadvantage, stress, and the likelihood of drug use in a sample of adults (N = 1,101). Using the 1995 Detroit Area Study in conjunction with tract-level data from the 1990 census, we find a positive relationship between neighborhood disadvantage and drug use, and this relationship remains statistically significant net of controls for individual-level socioeconomic status. Neighborhood disadvantage is moderately associated with drug related behaviors, indirectly through increased social stressors and higher levels of psychological distress among residents of disadvantaged neighborhoods. A residual effect of neighborhood disadvantage remains, net of a large number of socially relevant controls. Finally, results from interactive models suggest that the relationship between neighborhood disadvantage and drug use is most pronounced among individuals with lower incomes.

The Effect of Implied Orientation Derived from Verbal Context on Picture Recognition

Abstract: Perceptual symbol systems assume an analogue relationship between a symbol and its referent, whereas amodal symbol systems assume an arbitrary relationship between a symbol and its referent. According to perceptual symbol theories, the complete representation of an object, called a simulation, should reflect physical characteristics of the object. Amodal theories, in contrast, do not make this prediction. We tested the hypothesis, derived from perceptual symbol theories, that people mentally represent the orientation of an object implied by a verbal description. Orientation (vertical-horizontal) was manipulated by having participants read a sentence that implicitly suggested a particular orientation for an object. Then recognition latencies to pictures of the object in each of the two orientations were measured. Pictures matching the orientation of the object implied by the sentence were responded to faster than pictures that did not match the orientation. This finding is interpreted as offering support for theories positing perceptual symbol systems.

Heavy-fermion superconductivity in CeCoIn5 at 2.3 K

Abstract: We report the observation of heavy-fermion superconductivity in CeCoIn5 at Tc = 2.3 K. When compared to the pressure-induced Tc of its cubic relative CeIn3 (Tc~200 mK), the Tc of CeCoIn5 is remarkably high. We suggest that this difference may arise from magnetically mediated superconductivity in the layered crystal structure of CeCoIn5.

Climatic and environmental change in Africa during the last two centuries

Abstract: Climatic and environmental changes in Africa during the last 2 centuries have been examined, using both systematic rainfall records and proxy information concerning lakes and rivers and the occurrence of famine and drought. The rainfall records provide excellent detail for the 20th century. The proxy data have been used to produce a semi-quantitative data set spanning most of the continent and having an annual time resolution. These provide an overview of conditions during the 19th century. Various issues related to the causes of these 2 centuries of variability are also considered: atmospheric and oceanic processes, desertification, surface albedo, mineral dust and hydrological feedbacks. The most significant climatic change that has occurred has been a long-term reduction in rainfall in the semi-arid regions of West Africa. This was on the order of 20 to 40% in parts of the Sahel. There have been 3 decades of protracted aridity. Nearly all of Africa has been affected by increased aridity, particularly since the 1980s. Few changes in temperature have been demonstrated. These have occurred on a much smaller scale and are of considerably lower magni- tude than those over the continents. The rainfall conditions over Africa during the last 2 to 3 decades are not unprecedented. A similar dry episode prevailed during most of the first half of the 19th cen- tury. By mid-century, conditions more typical of the 'normal' for the current century again prevailed. Thus, the 3 decades of dry conditions evidenced in the Sahel are not in themselves evidence of irre- versible global change. On the other hand, the processes controlling rainfall over most of the conti- nent are now reasonably well understood. One of the most important factors, particularly in the Sahel, is sea-surface temperatures. It has been hypothesized that anthropogenic changes in the land surface, particularly land use change and desertification, have contributed significantly to the decline in rainfall. Current evidence suggests that if changes in the land surface (e.g., vegetation cover, sur- face albedo, soil moisture) signficantly impact climate, they are much more strongly controlled by natural climate variations, such as the recent decline in rainfall, than by human-induced land-use change or degradation. Unfortunately, we still do not have any accurate large-scale assessments of the extent, nature and degree of such changes. The dreaded 'desertification' process appears to be confined to relatively small scales. However, there is still cause for concern because the net effect of the various feedback processes involved in land degradation appears to be destabilization of ecosys- tems. Thus, a priority must be large-scale monitoring of the land surface and estimates of the degree of change.

Mechanism of Polyelectrolyte Multilayer Growth: Charge Overcompensation and Distribution

Abstract: A mechanism for distributing excess polymer surface charge is used to model the growth of multilayers of strongly charged polyelectrolytes. Two parameters are required for the semiempirical analysis: the surface, or unrestricted, charge overcompensation level, φ, which is assumed to decrease exponentially from the film surface to bulk, and the characteristic length for this decay, lcp, which is termed the charge penetration length. Modeling of the data reveals that only modest levels of polymer charge overcompensation are required to account for large increments in polymer thickness, realized at high salt concentration, since the excess charge is distributed over several “layers”. Experimentally, φ appears to be roughly independent of salt concentration. The thickness increment is primarily controlled by lcp, which is about 2.5 nominal layers for the system studied. Whereas the growth conditions and polyelectrolyte type lead to the formation of intrinsically compensated multilayers in this work, conditio...

Swelling and Smoothing of Polyelectrolyte Multilayers by Salt

Abstract: By use of in situ atomic force microscopy, polyelectrolyte multilayers were shown to swell on exposure to solutions containing salt. The quasilinear swelling response, used to estimate swelling coefficients and equilibria, exhibits orders of magnitude of difference, depending on the pair of polyelectrolytes constituting the multilayer. The surface roughness of as-made multilayers was observed to decrease significantly upon annealing in salt solutions.

Critical Elements of Classroom and Small-Group Instruction Promote Reading Success in All Children.

Abstract: The components of effective reading instruction are the same whether the focus is prevention or intervention: phonemic awareness and phonemic decoding skills, fluency in word recognition and text processing, construction of meaning, vocabulary, spelling, and writing. Findings from evidence-based research show dramatic reductions in the incidence of reading failure when explicit instruction in these components is provided by the classroom teacher. To address the needs of children most at risk of reading failure, the same instructional components are relevant but they need to be made more explicit and comprehensive, more intensive, and more supportive in small-group or one-on-one formats. The argument is made that by coordinating research evidence from effective classroom reading instruction with effective small-group and one-on-one reading instruction we can meet the literacy needs of all children.

Spin waves and electronic interactions in La2CuO4

Abstract: The magnetic excitations of the square-lattice spin-1/2 antiferromagnet and high- T(c) parent compound La2CuO4 are determined using high-resolution inelastic neutron scattering. Sharp spin waves with absolute intensities in agreement with theory including quantum corrections are found throughout the Brillouin zone. The observed dispersion relation shows evidence for substantial interactions beyond the nearest-neighbor Heisenberg term which can be understood in terms of a cyclic or ring exchange due to the strong hybridization path around the Cu4O4 square plaquettes.

Effects of chronic exposure to cocaine are regulated by the neuronal protein Cdk5

Abstract: Cocaine enhances dopamine-mediated neurotransmission by blocking dopamine re-uptake at axon terminals. Most dopamine-containing nerve terminals innervate medium spiny neurons in the striatum of the brain. Cocaine addiction is thought to stem, in part, from neural adaptations that act to maintain equilibrium by countering the effects of repeated drug administration. Chronic exposure to cocaine upregulates several transcription factors that alter gene expression and which could mediate such compensatory neural and behavioural changes. One such transcription factor is DeltaFosB, a protein that persists in striatum long after the end of cocaine exposure. Here we identify cyclin-dependent kinase 5 (Cdk5) as a downstream target gene of DeltaFosB by use of DNA array analysis of striatal material from inducible transgenic mice. Overexpression of DeltaFosB, or chronic cocaine administration, raised levels of Cdk5 messenger RNA, protein, and activity in the striatum. Moreover, injection of Cdk5 inhibitors into the striatum potentiated behavioural effects of repeated cocaine administration. Our results suggest that changes in Cdk5 levels mediated by DeltaFosB, and resulting alterations in signalling involving D1 dopamine receptors, contribute to adaptive changes in the brain related to cocaine addiction.