304 research outputs found

    How Exemplary Educational Leadership Preparation Programs Hone the Interpersonal-Intrapersonal (i2) Skills of Future Leaders

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    John P. Kotter argues that business schools continue to prepare leaders for 20th century needs, as they typically teach students how to manage an organization, rather than how to lead one. In this article, we explore how Kotter’s assertion applies to educational leadership preparation programs. We examine the ways a purposive sample of exemplary programs structure and implement learning experiences for aspiring educational leaders. Leveraging our findings from these cases and the literature on transformational learning and leadership, we argue that today’s programs should include “powerful learning experiences” that challenge and coach leadership candidates to build the skills and capacities necessary to both manage and lead organizations. If educational leaders are the “driving subsystem” for school improvement efforts, then leadership preparation must move aspiring leaders beyond technical competence and toward the more transformational aspects of leading

    Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS).

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    The inclusion of a chapter on pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (or PANDAS) is essential to provide a history of the disease and provide current information about its association with Streptococcus pyogenes (group A streptococci), tics, obsessive compulsive disorder (OCD) and its relationship to Sydenham chorea (SC), which is the neurologic manifestation of acute rheumatic fever. PANDAS has been misunderstood and confusing to doctors since its discovery, but the original group of the first 50 cases as described by Dr Susan Swedo (Swedo, et al., 1998) has a similarity to Sydenham chorea that distinguishes this initial group from tic and OCD cases. As this chapter will examine, the acute onset is an important feature of these disorders, as are their piano-playing choreiform movements, enuresis, night-time fears, separation anxiety, learning regression, and handwriting disabilities. The most current literature, which has been recently published in the Journal of Child and Adolescent Psychopharmacology (Murphy, et al., 2015b; Murphy, Parker-Athill, Lewin, Storch, & Mutch, 2015a; Toufexis, et al., 2015; Gerardi, Casadonte, Patel, & Murphy, 2015; Chang, et al., 2015), provides new insight into the clinical phenotype of PANDAS; namely, a subgroup of pediatric acute-onset neuropsychiatric syndrome (PANS), which has been proposed to have multiple etiologies, including those that are genetic and immunologic, and that present either with or without preceding infections, such as with Streptococcus pyogenes (Toufexis, et al., 2015). PANS is a subtype of obsessive compulsive disorder (OCD) that presents with an abrupt onset or exacerbation of neuropsychiatric symptoms (Murphy, et al., 2015b), including moderate or severe OCD. Elevated anti-streptococcal antibody titers tended to have higher OCD severity and the symptoms tended to lead to sudden and severe impairment, due to comorbidities, such as anxiety, behavioral regression, depression, and suicidality. Comorbid tics in PANS were associated with decline in school performance, visuomotor impairment, eating disorders, deterioration of handwriting skills, and lower quality of life, as compared to children without tics (Murphy, et al., 2015b). In addition, clinical evaluation of youth with PANS and PANDAS and recommendations for diagnosis were reported from the 2013 PANS conference held at Stanford University where a group of clinicians and researchers who were academicians with clinical and research interest in PANDAS and PANS (Chang, et al., 2015). PANDAS is clearly a subtype of PANS (Murphy, et al., 2015b; Murphy, Parker-Athill, Lewin, Storch, & Mutch, 2015a; Chang, et al., 2015) and not all PANS cases have an underlying streptococcal infection—but all PANDAS cases are associated with streptococcal infections, at least temporally. When these diseases appear, treatment with antibiotics can be successful, and a treatment trial of cefdinir by Murphy and colleagues indicated that therapy with cefdinir, a β lactam antibiotic, provided notable improvements in tic symptoms rated by the Yale Global Tic Severity Scale (YGTSS) and OCD symptoms rated by the Children’s Yale-Brown Obsessive Compulsive Scale (CY-BOCS). However, the differences within the groups as a whole were not significant. β-lactam antibiotics have been proposed to be neuroprotective above and beyond their antibiotic efficacy (Murphy, Parker-Athill, Lewin, Storch, & Mutch, 2015a). Anti-neuronal autoantibodies against the brain in SC and PANDAS react with brain antigens including dopamine receptors (Cox, et al., 2013; Brimberg, et al., 2012), lysoganglioside (Kirvan, Swedo, Heuser, & Cunningham, 2003; Kirvan, Swedo, Snider, & Cunningham, 2006a), and tubulin (Kirvan, Cox, Swedo, & Cunningham, 2007), as well as the activation of the calcium calmodulin-dependent protein kinase II (CaM KII) in human neuronal cells (Kirvan, Swedo, Heuser, & Cunningham, 2003). Human anti-brain antibodies expressed in Tg mice targeted dopaminergic neurons and signaled the dopamine D2 receptor (D2R) (Cox, et al., 2013). Evidence strongly suggests that human anti-brain autoantibodies induced by Streptococcus pyogenes infections target the dopamine receptors (Cox, et al., 2013; Brimberg, et al., 2012) and that animal models immunized with the S. pyogenes antigen develop obsessive behaviors and movement problems, along with antibodies that react with the dopamine receptors and signal the CaMKII, similar to antibodies found in humans with SC and PANDAS (Brimberg, et al., 2012; Lotan, et al., 2014a)

    Single-electron transport driven by surface acoustic waves: moving quantum dots versus short barriers

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    We have investigated the response of the acoustoelectric current driven by a surface-acoustic wave through a quantum point contact in the closed-channel regime. Under proper conditions, the current develops plateaus at integer multiples of ef when the frequency f of the surface-acoustic wave or the gate voltage Vg of the point contact is varied. A pronounced 1.1 MHz beat period of the current indicates that the interference of the surface-acoustic wave with reflected waves matters. This is supported by the results obtained after a second independent beam of surface-acoustic wave was added, traveling in opposite direction. We have found that two sub-intervals can be distinguished within the 1.1 MHz modulation period, where two different sets of plateaus dominate the acoustoelectric-current versus gate-voltage characteristics. In some cases, both types of quantized steps appeared simultaneously, though at different current values, as if they were superposed on each other. Their presence could result from two independent quantization mechanisms for the acoustoelectric current. We point out that short potential barriers determining the properties of our nominally long constrictions could lead to an additional quantization mechanism, independent from those described in the standard model of 'moving quantum dots'.Comment: 25 pages, 12 figures, to be published in a special issue of J. Low Temp. Phys. in honour of Prof. F. Pobel

    The angiotensin II type I receptor contributes to impaired cerebral blood flow autoregulation caused by placental ischemia in pregnant rats

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    BACKGROUND: Placental ischemia and hypertension, characteristic features of preeclampsia, are associated with impaired cerebral blood flow (CBF) autoregulation and cerebral edema. However, the factors that contribute to these cerebral abnormalities are not clear. Several lines of evidence suggest that angiotensin II can impact cerebrovascular function; however, the role of the renin angiotensin system in cerebrovascular function during placental ischemia has not been examined. We tested whether the angiotensin type 1 (AT1) receptor contributes to impaired CBF autoregulation in pregnant rats with placental ischemia caused by surgically reducing uterine perfusion pressure. METHODS: Placental ischemic or sham operated rats were treated with vehicle or losartan from gestational day (GD) 14 to 19 in the drinking water. On GD 19, we assessed CBF autoregulation in anesthetized rats using laser Doppler flowmetry. RESULTS: Placental ischemic rats had impaired CBF autoregulation that was attenuated by treatment with losartan. In addition, we examined whether an agonistic autoantibody to the AT1 receptor (AT1-AA), reported to be present in preeclamptic women, contributes to impaired CBF autoregulation. Purified rat AT1-AA or vehicle was infused into pregnant rats from GD 12 to 19 via mini-osmotic pumps after which CBF autoregulation was assessed. AT1-AA infusion impaired CBF autoregulation but did not affect brain water content. CONCLUSIONS: These results suggest that the impaired CBF autoregulation associated with placental ischemia is due, at least in part, to activation of the AT1 receptor and that the RAS may interact with other placental factors to promote cerebrovascular changes common to preeclampsia

    Quasi-Normal Modes of Schwarzschild Anti-De Sitter Black Holes: Electromagnetic and Gravitational Perturbations

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    We study the quasi-normal modes (QNM) of electromagnetic and gravitational perturbations of a Schwarzschild black hole in an asymptotically Anti-de Sitter (AdS) spacetime. Some of the electromagnetic modes do not oscillate, they only decay, since they have pure imaginary frequencies. The gravitational modes show peculiar features: the odd and even gravitational perturbations no longer have the same characteristic quasinormal frequencies. There is a special mode for odd perturbations whose behavior differs completely from the usual one in scalar and electromagnetic perturbation in an AdS spacetime, but has a similar behavior to the Schwarzschild black hole in an asymptotically flat spacetime: the imaginary part of the frequency goes as 1/r+, where r+ is the horizon radius. We also investigate the small black hole limit showing that the imaginary part of the frequency goes as r+^2. These results are important to the AdS/CFT conjecture since according to it the QNMs describe the approach to equilibrium in the conformal field theory.Comment: 2 figure

    RNA interference therapeutics targeting angiotensinogen ameliorate preeclamptic phenotype in rodent models

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    Preeclampsia, with the hallmark features of new-onset hypertension and proteinuria after 20 weeks of gestation, is a major cause of fetal and maternal morbidity and mortality. Studies have demonstrated a role for the renin-angiotensin system (RAS) in its pathogenesis; however, small-molecule RAS blockers are contraindicated because of fetal toxicity. We evaluated whether siRNA targeting maternal hepatic angiotensinogen (Agt) could ameliorate symptoms of preeclampsia without adverse placental or fetal effects in 2 rodent models. The first model used a cross of females expressing human Agt with males expressing human renin, resulting in upregulation of the circulating and uteroplacental RAS. The second model induced ischemia/reperfusion injury and subsequent local and systemic inflammation by surgically reducing placental blood flow midgestation (reduced uterine perfusion pressure [RUPP]). These models featured hypertension, proteinuria, and fetal growth restriction, with altered biomarkers. siRNA treatment ameliorated the preeclamptic phenotype in both models, reduced blood pressure, and improved intrauterine growth restriction, with no observed deleterious effects on the fetus. Treatment also improved the angiogenic balance and proteinuria in the transgenic model, and it reduced angiotensin receptor activating antibodies in both. Thus, an RNAi therapeutic targeting Agt ameliorated the clinical sequelae and improved fetal outcomes in 2 rodent models of preeclampsia

    Blockade of CD40 ligand for intercellular communication reduces hypertension, placental oxidative stress, and AT1-AA in response to adoptive transfer of CD4(+) T lymphocytes from RUPP rats

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    Preeclampsia (PE) is associated with altered immune activation during pregnancy. We have previously shown that adoptive transfer of CD4+ T cells from the reduced uterine perfusion pressure (RUPP) rat model of PE increases blood pressure, oxidative stress (ROS), and inflammation in normal pregnant recipient rats. The objective of this study was to determine if blockade of communication via the CD40-CD40 ligand (CD40L) interaction between placental ischemia-induced CD4+ T cells with endogenous normal pregnant (NP) cells would improve pathophysiology that was previously observed in NP recipient rats of RUPP CD4+ T cells. Splenic CD4+ T lymphocytes were magnetically separated, incubated with 2.5 {mu}g/ml anti-CD40 ligand ({alpha}CD40L) overnight, and transferred into NP rats on day 12 of gestation (NP+RUPP CD4+ T+anti-CD40L). On day 19 of gestation, blood pressure (MAP), blood, and tissues were collected. MAP was 99 +/- 2 in NP (n = 13), 116 +/- 4 in NP+RUPP CD4+ T cells (n = 7; P < 0.01); MAP only increased to 104 +/- 2 in NP+RUPP CD4+ T cells+CD40L (n = 24) (P < 0.05 vs. NP+RUPP CD4+ T cells). Mechanisms of hypertension in response to RUPP CD4+ T cells include endothelin-1 (ET-1), ROS, and angiotensin II type I receptor (AT1-AA) were analyzed. Inhibition of CD40L binding reduced placental ET-1 to 2.3-fold above NP rats and normalized placental ROS from 318.6 +/- 89 in NP+RUPP CD4+ T cells (P < 0.05) to 118.7 +/- 24 in NP+RUPP CD4+ T+anti-CD40L (P < 0.05). AT1-AA was also normalized with inhibition of CD40L. These data suggest that placental ischemia-induced T-cell communication via the CD40L is one important mechanism leading to much of the pathophysiology of PE

    Detecting microstructural deviations in individuals with deep diffusion MRI tractometry

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    Most diffusion magnetic resonance imaging studies of disease rely on statistical comparisons between large groups of patients and healthy participants to infer altered tissue states in the brain; however, clinical heterogeneity can greatly challenge their discriminative power. There is currently an unmet need to move away from the current approach of group-wise comparisons to methods with the sensitivity to detect altered tissue states at the individual level. This would ultimately enable the early detection and interpretation of microstructural abnormalities in individual patients, an important step towards personalized medicine in translational imaging. To this end, Detect was developed to advance diffusion magnetic resonance imaging tractometry towards single-patient analysis. By operating on the manifold of white-matter pathways and learning normative microstructural features, our framework captures idiosyncrasies in patterns along white-matter pathways. Our approach paves the way from traditional group-based comparisons to true personalized radiology, taking microstructural imaging from the bench to the bedside
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