78,361 research outputs found
Transforming Power Relationships: Leadership, Risk, and Hope. IHS Political Science Series No. 135, May 2013
No full textChronic communal conflicts resemble the prisoner’s dilemma. Both communities prefer peace to war. But neither trusts the other, viewing the other’s gain as its own loss, so
potentially shared interests often go unrealized.
Achieving positive-sum outcomes from apparently zero-sum struggles requires a kind of riskembracing leadership. To succeed leaders must: a) see power relations as potentially
positive-sum; b) strengthen negotiating adversaries instead of weakening them; and c) demonstrate hope for a positive future and take great personal risks to achieve it.
Such leadership is exemplified by Nelson Mandela and F.W. de Klerk in the South African democratic transition. To illuminate the strategic dilemmas Mandela and de Klerk faced, we examine the work of Robert Axelrod, Thomas Schelling, and Josep Colomer, who highlight important dimensions of the problem but underplay the role of risk-embracing leadership. Finally we discuss leadership successes and failures in the Northern Ireland settlement and the Israeli-Palestinian conflict
Single and combined effects of sympathetic and parasympathetic activity on perceptual sensitivity and attention
No full textPulse rate and cephalic pulse volume were recorded from 17 male and 37 female normal subjects during performance of an attentional task under high and low stress conditions. Verbal threshold (perceptual sensitivity) and word recognition (attention) were assessed using a visual verbal recognition task. Subjects were divided at the median for pulse rate and pulse volume during baseline, instruction, and task periods and grouped in terms of these two measures to represent different patterns of parasympathetic (vagal) and sympathetic activity. Analysis of variance was used to examine the effects of gender, stress condition, and autonomic pattern on autonomic activity, perceptual sensitivity, and attentional performance. Gender showed significant effects for pulse rate with higher scores for women during the instruction and task periods. High stress reduced perceptual sensitivity and resulted in better attentional performance. Whereas stress-induced sympathetic activity was related to low perceptual sensitivity and good attentional performance, high sympathetic in conjunction with low vagal baseline activity predicted relatively high perceptual sensitivity and poor attentional performance. Low or high baseline activity in both autonomic systems predicted low perceptual sensitivity and good attentional performance. Predictions of perception and attention can be improved by examining the effects of patterns of sympathetic and parasympathetic activity
Probing Topological Superconductivity of oxide nanojunctions using fractional Shapiro steps
No full textWe theoretically discuss the emergence of fractional Shapiro steps in a Josephson junction created by confining a two-dimensional electron gas at an oxide interface. This phenomenon is induced by an alternating current of proper amplitude and frequency and can be tuned by a magnetic field applied perpendicular to the Rashba spin–orbit axis. The presence of fractional Shapiro steps can be associated with the creation of Majorana bound states at the boundaries of the superconducting leads. Our findings represent a route for the identification of topological superconductivity in non-centrosymmetric materials and confined systems in the presence of spin–orbit interaction, offering also new insights into recently explored frameworks
On the divisor function over Piatetski-Shapiro sequences
No full textsummary:Let be an integer part of and be the number of positive divisor of . Inspired by some results of M. Jutila (1987), we prove that for , where is the Euler constant and is the Piatetski-Shapiro sequence. This gives an improvement upon the classical result of this problem
Geo. Cohan's rag
No full textGift of Dr. Mary Jane Esplen.Piano. [instrumentation]C major [key]Slow-rag tempo [tempo]Ragtime. [form/genre]Portrait of Geo M. Cohan. [illustration]Starmer [engraver]Shapiro Music Publisher, New York. [dealer stamp]Publisher's advertisement on back cover. [note
Local cerebral blood flow during lidocaine-induced seizures in rats
No full textNeurophysiologic and local cerebral metabolic mapping techniques indicate that seizures associated with lidocaine toxicity originate in subcortical brain structures. Normally local cerebral blood flow (l-CBF) is quantitatively coupled to local cerebral metabolic rate for glucose (l-CMR(g)). In the present study the response of l-CBF to a lidocaine-induced preconvulsive state (localized seizure activity in the absence of a grand mal seizure) was evaluated in rats anesthetized with 60% nitrous oxide. Lidocaine administered as a bolus (20 mg/kg) followed by an infusion (4 mg/kg) over 5.5 min resulted in progressive alteration in the electroencephalogram (EEG). L-CBF was studied with the 14 C-iodoantypyrine autographic method when the preconvulsive EEG pattern consisted of a repetitive spike and wave complex at a frequency of 14 ± 1·min -1 complexes, superimposed on practically isoelectric background activity. Under these conditions high doses of lidocaine significantly (P < 0.05) decreased (range -30% to -68%) l-CBF in 71% of the 34 brain regions studied. The greatest exception to this trend for l-CBF to decrease was observed in the limbic system wherein l-CBF remained within control ranges in eight of the 11 structures evaluated. Qualitative comparison of lidocaine l-CBF changes with l-CMR(g) changes obtained under similar conditions indicated a general trend for local flow and metabolism to decrease in parallel. Exceptions to this were confined to certain limbic areas (amygdala and hippocampus) in which increases in l-CMR(g) were more than 100% greater than slight (P > 0.05) increases in l-CBF. This comparison demonstrates uncoupling of local brain metabolism from blood flow during lidocaine-induced subcortical epileptoid discharges (preconvulsive state) in areas recognized to be prone to irreversible damage when seizure activity is much prolonged beyond the duration of this study
Some Lower Bounds in the B. and M. Shapiro Conjecture for Flag Varieties
No full textThe B. and M. Shapiro conjecture stated that all solutions of the Schubert Calculus problems associated with real points on the rational normal curve should be real. For Grassmannians, it was proved by Mukhin, Tarasov, and Varchenko. For flag varieties, Sottile found a counterexample and suggested that all solutions should be real under certain monotonicity conditions. In this paper, we compute lower bounds on the number of real solutions for some special cases of the B. and M. Shapiro conjecture for flag varieties, when Sottile's monotonicity conditions are not satisfied. © 2010 Springer Science+Business Media, LLC.BROWDER F, 1976, P S PURE MATH AM MAT, V28; Degtyarev A. I., 2000, USP MAT NAUK, V55, P129; Eremenko A, 2002, ANN MATH, V155, P105, DOI 10.2307-3062151; EREMENKO A, 2005, ELEMENTARY PROOF B M; Eremenko A, 2002, DISCRETE COMPUT GEOM, V28, P331, DOI 10.1007-s00454-002-0735-x; Eremenko A, 2006, P AM MATH SOC, V134, P949, DOI 10.1090-S0002-9939-05-08048-2; FULTON W, 1984, CBMS REGIONAL C SERI, V54; GOLDBERG LR, 1991, ADV MATH, V85, P129, DOI 10.1016-0001-8708(91)90052-9; Hodge W., 1952, METHODS ALGEBRAIC GE, V2; Itenberg I, 2003, INT MATH RES NOTICES, P2639; Mikhalkin G, 2003, CR MATH, V336, P629, DOI 10.1016-S1631-073X(03)00104-3; Mukhin E, 2009, ANN MATH, V170, P863; Pandharipande R, 2008, J AM MATH SOC, V21, P1169, DOI 10.1090-S0894-0347-08-00597-3; Petersen TK, 2009, J ALGEBR COMB, V30, P19, DOI 10.1007-s10801-008-0150-3; Purbhoo K, 2010, ADV MATH, V224, P827, DOI 10.1016-j.aim.2009.12.013; Ruffo J, 2006, EXP MATH, V15, P199, DOI 10.1080-10586458.2006.10128954; Schubert H., 1979, KALKUL ABZAHLENDEN G; SOLOMON J, 2006, ARXIVMATH0606429V1; Soprunova E, 2006, ADV MATH, V204, P116, DOI 10.1016-j.aim.2005.05.016; SOTTILE F, 2010, ARXIVMATH0609829V2; Sottile F, 1997, DUKE MATH J, V87, P59, DOI 10.1215-S0012-7094-97-08703-2; Sottile F, 2000, EXP MATH, V9, P161; Sottile F, 2010, B AM MATH SOC, V47, P31; Stanley R.P., 1999, ENUMERATIVE COMBINAT, V2; Welschinger J. Y., 2010, ARXIV10032707V1; Welschinger JY, 2003, CR MATH, V336, P341, DOI 10.1016-S1631-073X(03)00059-112
Local cerebral blood flow with fentanyl-induced seizures.
No full textLocal cerebral blood flow (LCBF) was evaluated with the [ 14 C]iodoantipyrine quantitative autoradiographic technique in 29 brain structures in conscious control rats and during fentanyl-induced electroencephalographic (EEG) spike and/or seizure activity and in the postseizure EEG suppression phase. During spike activity, LCBF increased in all structures; the increase reached statistical significance (p<0.05) in the superior colliculus, sensorimotor cortex, and pineal body (+130%, +187%, and +185% from control, respectively). With progressive development of seizure activity, LCBF significantly increased in 24 brain structures (range, +58% to +231% from control). During the postseizure EEG suppression phase, LCBF remained elevated in all structures (+80% to +390% from control). The local cerebrovascular resistance (LCVR) significantly decreased in 10 of 29 structures with the onset of spike activity (range, -24% to -64%), and remained decreased in all brain structures during seizure activity (range, -34% to -67%) and during the EEG suppression phase (range, -24% to 74%). This reduction of LCVR represents a near maximal state of cerebrovasodilation during fentanyl-induced EEG seizure or postseizure suppression activity. The global nature of the LCBF elevation indicates that factors other than local metabolic control are responsible for CBF regulation during local seizure activit
Functional imaging reveals working memory and attention interact to produce the attentional blink
No full textCopyright @ 2012 Massachusetts Institute of Technology PressIf two centrally presented visual stimuli occur within approximately half a second of each other, the second target often fails to be reported correctly. This effect, called the attentional blink (AB; Raymond, J. E., Shapiro, K. L., & Arnell, K. M. Temporary suppression of visual processing in an RSVP task: An attentional blink? Journal of Experimental Psychology, Human Perception and Performance, 18, 849-860, 1992], has been attributed to a resource "bottleneck," likely arising as a failure of attention during encoding into or retrieval from visual working memory (WM). Here we present participants with a hybrid WM-AB study while they undergo fMRI to provide insight into the neural underpinnings of this bottleneck. Consistent with a WM-based bottleneck account, fronto-parietal brain areas exhibited a WM load-dependent modulation of neural responses during the AB task. These results are consistent with the view that WM and attention share a capacity-limited resource and provide insight into the neural structures that underlie resource allocation in tasks requiring joint use of WM and attention.This research was supported by a project grant (071944) from the Wellcome Trust to Kimron Shapiro
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