Positive Ends Research Articles

When "Helping Someone Else" Is the Right Answer: Bridging Cultures in Assessment

The Bridging Cultures Project is a longitudinal action-research project that began with teacher professional development on differences in cultural values orientations that have been associated with conflicts between home and school. Teachers used the cultures values framework of individualism and collectivism as a starting point for exploring students' home values and devising new strategies that were more culturally harmonious for their students. Data show how elementrary school teachers have used immigrant Latino students' value of helping, in both instruction and test preparation, to positive ends. Two questions are addressed. First, how did teachers' knowledge of children's home-culture value of helping affect their assessment practices? Second, where does helping leave off and cheating begin? The implications of teachers' beliefs about what constitutes helping versus cheating in terms of their potential effects on students are explored in light of cultural value systems. Keywords: assessment, culture, helping, cheating, professional development, Latino

Charles Johnson's Middle Passage: Fictionalizing History and Historicizing Fiction

Charles Johnson's Middle Passage owes much to contemporary and postmodern themes and techniques, as it asks us to reconsider any preconceived notions we might have of identity, history, and historical accuracy. But the novel can also be placed in the slave narrative tradition, a tradition that concerns individual growth in spite of tremendous odds and contains an explicit political agenda. However, after reading the novel, one wonders to what extent the story's lead character, Rutherford Calhoun, does grow, does develop into a different, changed, and, assumedly, better person, and, furthermore, to what end is Johnson's political commentary concerning slavery, freedom, and the contemporary status of African American men and women. Johnson radically rewrites the traditional slave narrative, filling in a number of interpersonal, philosophical gaps whose absences are evident in the originals. His focus is varied, with interests in relationships, home, narration, and revision. He especially focuses on the veracity of written history, the connections and distinctions between what is written and what has been experienced. He demonstrates how slippery the written document can be and how it might readily be re-inscribed and overwritten for positive or sinister ends. Johnson is also profoundly interested in the nature of writing/ creating/producing. By fictionalizing a historical event, he suggests that history, once it takes form as words, can be viewed as a fiction (something which might or might not contain truths and omissions).

Discourse Communities and the Discourse of Experience

Discourse communities are groups of people who share common ideologies, and common ways of speaking about things. They can be sharply or loosely defined. We are each members of multiple discourse communities. Discourse can colonize the members of discourse communities, taking over domains of thought by means of ideology. The development of new discourse communities can serve positive ends, but discourse communities create risks as well. In our own work on the narratives of people with interests in health care, for example, we find that patients speak of their illness experiences as victims of circumstance; policy makers construct adverse experiences and challenges as opportunities to be taken; health care workers speak from a mixed perspective, seeing themselves as both victims and opportunists depending on context. To be trapped within the discourse of a particular community is to put at risk the ability to communicate across discourses. Membership of a discourse community can impair the habit of critique, and deny opportunities for heteroglossic discourse. Privileging critique as a mode of discourse perhaps might define the ethical community, suggesting that ethical community may be an antidote to the constraining effects of conventional discourse community.

The Art of Genocide

Rumours of art's death have been highly exaggerated. Such is the (negative) conclusion reached by two recent studies that explore with fresh insight Germany's art and architectural worlds during and after the Third Reich. Under the Nazi regime, idealist and transcendent notions of the aesthetic all but disappeared given the overtly propagandistic purpose Hitler and his minions compelled the arts to serve. After 1945, however, belief in art's 'autonomy' and 'freedom' reappeared and flourished and not for wholly positive ends. Within the context of Germany's attempt to come to terms with its unmasterable past, art's allegedly transcendent quality served the sinister purpose of exonerating art world luminaries of their complicity in some of the Third Reich's most criminal acts. Post-war judges concluded, time after time, that art had nothing to do with politics that those so intimately involved in 'culture' between 1933 and 1945 could scarcely have been guilty of political wrong-doing. In their recently published books, Jonathan Petropoulos and Paul Jaskot expose the political instrumentality of such notions of artistic autonomy. Petropoulos's Faustian Bargain: The Art World in Nazi Germany and Jaskot's Architecture of Oppression: The SS, Forced Labor and the Nazi Monumental Building Economy take as their moral centre and point of departure the postWorld War Two oblivion that made it possible for unrepentant art-world criminals to escape prosecution. Petropoulos's and Jaskot's texts cause us to look anew at such familiar luminaries as Albert Speer and Arno Breker and to consider, as well, a host of other art world figures who operated in their half-light. Through their meticulous sifting of previously unexplored archival materials, both authors uncover excoriating evidence that made its way neither into the denazification proceedings nor into the Nuremberg trials of the post-war era. These are sober and sobering accounts that fundamentally reorient our notions about the role of the arts administration and the nature of art and

CYTOKINESIS AND BUILDING OF THE CELL PLATE IN PLANTS.

Cytokinesis in plant cells is more complex than in animals, as it involves building a cell plate as the final step in generating two cells. The cell plate is built in the center of phragmoplast by fusion of Golgi-derived vesicles. This step imposes an architectural problem where ballooning of the fused structures has to be avoided to create a plate instead. This is apparently achieved by squeezing the vesicles into dumbbell-shaped vesicle-tubule-vesicle (VTV) structures with the help of phragmoplastin, a homolog of dynamin. These structures are fused at their ends in a star-shaped body creating a tubulovesicular "honeycomb-like" structure sandwiched between the positive ends of the phragmoplast microtubules. This review summarizes our current understanding of various mechanisms involved in budding-off of Golgi vesicles, delivery and fusion of vesicles to initiate cell plate, and the synthesis of polysaccharides at the forming cell plate. Little is known about the molecular mechanisms involved in determining the site, direction, and the point of attachment of the growing cell plate with the parental cell wall. These gaps may be filled soon, as many genes that have been identified by mutations are analyzed and functions of their products are deciphered.

Spatially Selective Photochemical Reduction of Silver on the Surface of Ferroelectric Barium Titanate

When BaTiO3 is immersed in an aqueous AgNO3 solution and illuminated by UV light, silver metal deposits on the surface in patterns determined by the ferroelectric domain structure. Because the photochemical reduction of Ag occurs preferentially on the positive ends of the dipoles, metal patterns with submicron dimensions are produced. The static dipolar field in certain domains is thought to promote the transport of photogenerated electrons to the solid−liquid interface where they reduce silver cations.

The effects of interpersonal and personal agency on perceived control and psychological well-being in adulthood.

A theoretical model that links social support with global beliefs in primary control and provides a developmental perspective on how normative age-related changes alter control beliefs was examined with data from 482 adults aged 18 to 93. Generalized belief in primary control was hypothesized to have a direct positive effect on psychological well-being and to arise from two distinct sources: (a) interpersonal agency (obtaining positive ends through interactions with others) and (b) personal agency (achieving desired outcomes on one's own behalf). Age was believed to affect both types of agency indirectly as a result of age-related changes in physical health and emotional support. Although physical health was presumed to have a direct positive effect on psychological well-being, the effect of emotional support on well-being was mediated by interpersonal agency and perceived primary control. Structural equation modeling analyses with the EQS 5.4 program revealed good model fit (goodness-of-fit index = .98, comparative fit index = .94, root mean square residual [RMR] = .02, standardized RMR = .05, root mean square error of approximation = .06) after a negative direct path from age to generalized beliefs in primary control was added to the a priori model.

The Dynamics of Microtubules in Cultured Cells

The behavior of microtubules in cultured cells in a cooled matrix after the microinjection of fluorescent tubulin was studied using a frame recording with a digital camcorder. In the cell lamella, the positive ends of individual microtubules extend and shorten at random. The histograms of rate distribution have an almost normal distribution with a mode close to 0. The maximum rate of lengthening and shortening reaches 30 and 50 μm/min, respectively. The positive ends of microtubules in PtK cells were in an equilibrium state, while in murine embryonic fibroblasts and Vero cells, they were usually displaced to the cell edge. Free microtubules were present in the cells of all three cultures. In the epithelial cells, they were numerous and relatively stable, while in the fibroblasts, they occurred rarely and were depolymerized at the proximal end. Free microtubules in PtK cells appeared mostly due to spontaneous assembly in the cytoplasm (not in the relationship with the preexisting microtubules) and, more rarely, due to breakage of long microtubules. Separation of microtubules from the centrosome is a very rare event. Unlike positive ends that were characterized by dynamic instability, negative ends were stable and were sometimes depolymerized. When long microtubules were broken, new negative ends were formed that were, as a rule, stable, while in the lamella of fibroblasts (in murine embryonic fibroblasts and Vero cells), new negative ends were immediately depolymerized: free microtubules existed in these cells no more than 1–2 min. A diffusion model has been proposed where the behavior of microtubule ends is considered as unidimensional diffusion. The coefficient of diffusion of positive ends in the epithelial cells is several times less than in the fibroblasts, thus suggesting a higher rate of tubulin metabolism in the fibroblasts as compared to the epithelium. The results obtained indicate that for the exchange of long microtubules, the dynamic instability is not sufficient. In the fibroblasts, their exchange takes place mostly at the expense of depolymerization of the liberating negative ends, which agrees with the previously proposed conveyer hypothesis of microtubule assembly on the centrosome.

Photochemical Reduction and Oxidation Reactions on Barium Titanate Surfaces

AbstractThe influence of the ferroelectric domain structure of BaTiO3 on the photochemical reactions that occur on its surface has been examined using atomic force microscopy. Both the photochemical reduction of aqueous silver cations and the oxidation of steric acid thin films were studied. During reduction, silver selectively deposits on the surface in patterns determined by the ferroelectric domain structure. Based on the analysis of domain polarization in single crystals, we find that the photochemical reduction reaction occurs preferentially on the positive ends of the dipoles. The most likely explanation for this phenomenon is that when the static dipolar field is oriented with the positive end of the dipole on the surface, photogenerated electrons are driven to the solid-liquid interface where they reduce metal cations. The oxidation of steric acid films, on the other hand, is not spatially selective. During oxidation, the films dissipate uniformly as they are converted to CO2 and H2O. In this case, we conclude that the oxidation occurs indirectly. Photogenerated holes create hydroxyl radicals which can migrate on the surface before reacting with the steric acid molecules.

Positive and Negative Creativity in Groups, Institutions, and Organizations: A Model and Theoretical Extension

Potential environmental and individual influences on creativity at work are described with an emphasis on how they relate to the possibility that creativity can be directed toward either positive or negative ends. A model of the psychological processes that might underlie positive and negative creativity is briefly delineated, and some outcomes of each type of creativity are outlined. The main focus is on the factors that might trigger the processes of and outcomes from positive and negative creativity and only tangentially on the cognitive processes underlying creativity and on the organizational outcomes of creativity. Literature from settings other than organizations (e.g., families, schools) that have been subject to limited theoretical and empirical attention of scholars of organizational and group processes and outcomes is mustered to support the theory.

Neuropathic pain: Between the positive and negative ends

Neuropathic pain: Between the positive and negative ends

Polarity of microtubule assemblies during neuronal cell migration.

The active migration of neurons from their sites of origin to their final destinations requires the unidirectional translocation of the nuclei and somatic cytoplasm within the growing leading processes. To explore the cellular machinery underlying this translocation, we determined the polarity of microtubules situated within the leading and trailing processes of migrating cerebellar granule cells in situ. Our analysis reveals that the newly assembled positive ends of the microtubules in the leading process uniformly face the growing tip, while their disintegrating negative ends face the nucleus. In the trailing process, by contrast, microtubule arrays are of mixed polarity. We suggest that the dynamics of slow polymerization in combination with fast disintegration of oriented microtubules create "push" and "pull" forces that contribute to the piston-like saltatory displacement of the nucleus and cytoplasm within the membrane cylinder of the leading process of the migrating neuron.

Cytoskeletal rearrangements and the functional role of T-plastin during entry of Shigella flexneri into HeLa cells.

Shigella flexneri is an enteroinvasive bacterium which causes bacillary dysentery in humans. A major feature of its pathogenic potential is the capacity to invade epithelial cells. Shigella entry into epithelial cells is considered a parasite-induced internalization process requiring polymerization of actin. Here we describe the cytoskeletal rearrangements during S. flexneri invasion of HeLa cells. After an initial contact of the bacterium with the cell surface, distinct nucleation zones of heavy chain actin polymerization appear in close proximity to the contact site underneath the parasite with long filaments being polymerized. These structures then push cellular protrusions that rise beside the entering bacterium, being sustained by tightly bundled long actin filaments organized in parallel orientation with their positive ends pointing to the cytoplasmic membrane. Finally, the cellular projections coalesce above the bacterial body, leading to its internalization. In addition, we found the actin-bundling protein plastin to be concentrated in these protrusions. Since plastin is known to bundle actin filaments in parallel orientation, colocalization of parallel actin filaments and plastin in the cellular protrusions strongly suggested a functional role of this protein in the architecture of parasite-induced cellular projections. Using transfection experiments, we show the differential recruitment of the two plastin isoforms (T- and L-) into Shigella entry zones. By transient expression of a truncated T-plastin which is deprived of one of its actin-binding sites, we also demonstrate the functional role of T-plastin in Shigella entry into HeLa cells.

Structure and properties of the metal–liquid interface

Theoretical results are given for simple dipolar liquids in contact with a metallic slab. The metal is treated by employing a jellium model together with density functional (DF) theory. The liquid structure at the interface is given by the reference hypernetted-chain (RHNC) approximation. The liquid and metal interact electrostatically and the coupled DF/RHNC equations are solved iteratively to obtain electron density distributions and metal–liquid correlation functions which are completely self-consistent. The electron density, liquid structure, and potential drop across the interface are discussed in detail. It is found that dipoles in contact with the metal prefer to orient perpendicular to the surface with their positive ends out. This is in accord with earlier calculations for dipolar monolayers on metal surfaces. Further from the surface, the dipolar orientations oscillate and the liquid structure rapidly decays to the bulk fluid limit.

Hydraulic jumps on adverse slopes

The adverse hydraulic jump has been investigated and analyzed in order to derive the limiting design parameters for this type of jump. The limiting design condition refers to the adverse jump when it occurs entirely on the adverse slope; as such, this jump was difficult to establish at Froude numbers less than 9 and required continuous tailwater adjustment to maintain a stationary position for Froude numbers less than about 4. It was found that the sequent depth as well as the roller length for the adverse hydraulic jump is less than that for a horizontal jump with the same approach conditions. The results for the limiting adverse jump are compared with published results on a stabilized jump that starts on a positive slope and ends on an adverse slope. A momentum based theory is presented to determine the sequent depth ratio. An empirical equation is presented for the roller length.

Influence of temperature variations on the visualisation of the ferroelectric domains of TGS and TAAP crystals by scanning electron microscopy

Abstract Temperature variations of aged Triglycine Sulphate (TGS) and Telluric Acid Ammonium Phosphate (TAAP) samples increase the contrast between positive and negative ends of domains observed with a scanning electron microscope. For freshly cleaved surface of TGS, an increase of temperature of 2°C inverts the contrast between these domains. When the temperature of the TGS samples increases continuously, we observe a deformation of the picture on the screen, but it is not observed for TAAP samples. Thermally stimulated electron emission is also observed and measured. These phenomena are due to the surface charges produced by the modification of the spontaneous electric polarization of the samples when the temperature varies.

Seizing the moment: Harnessing the information technologies

Abstract In this article, we review some of the historical trends and events that suggest the scope and power of the Information Revolution. We speculate how these trends and events may be interpreted in new models or theories of human affairs, in perhaps the greatest and most fundamental change since the latter part of the eighteenth century for human transactions of power of all kinds—political, economic, and military—and at all levels—global, national, and factional. Traditional hierarchies, based on the control of information, are being eroded and bypassed. At a time of great change, where institutions can provide for some measure of stability and continuity, many may be unable to function effectively in the face of a new abundance of public information. The relationships between information, the information technologies, and conflict are complex and not universally positive, but positive effects are evident and pose apparent opportunities to harness the information technologies to inhibit conflicts. We describe some of these opportunities in both general and specific terms. In general terms, we sketch the landscape of possibilities out to the horizon of the information technologies as they are currently understood, without regard to the limitations of politics, costs, or time. In these sketches we look at worlds in which anyone can listen or watch or broadcast anything that they want on global networks. We conclude with an initial agenda for research into issues that need to be addressed to properly support a program for exploring and investing in high‐leverage information initiatives to open societies and enhance human rights, thereby inhibiting conflict and promoting a more peaceful world. These are the issues that we will need to fully appreciate if we hope to make wise judgments in harnessing the Information Revolution to the positive and peaceful ends sought by most of the world public.

Expanded Head Surface EEG Electrode Array

Aided by computerized voltage topographic display, conventional time-series EEG display methods were expanded. Representations of both negative and positive ends of an equivalent current dipole can be localized in EEG sampled over the head surface. Intuitive EEG analysis can be applied to source localization in three dimensions of scalp focal epileptiform discharges.

A study on the pyroelectricity of a new polar crystal-tris(Hydroxymethyl)-aminomethane(TAM)

Abstract Tris(Hydroxymethyl)Aminomethane (TAM) is a polar organic crystal with pyroelectric properties. In this paper the pyroelectric coefficient, dielectric constant, loss tangent, a.c.-, d.c.-resistivity, P-E characteristic, and infrared transmissivity in a polar direction are reported. In addition, the samples were measured in both the positive and negative directions of the polar axis by means of the positron annihilation technique. In the positron annihilation lifetime and the intensity, obvious differences between the positive and negative ends were found. These differences demonstrate that the inclusions relate to structural factors, which principally affect crystal quality and its pyroelectric performance.

Evaluating the Growth of Helplessness Literature

Evaluating the Growth of Helplessness Literature