bluuebunny/crossref_metadata_2025_split huggingface dataset:
Making Sense of Distributed Leadership: Exploring the Multiple Usages of the Concept in the Field
Authors: Mayrowetz David 
Published: July 2008

Background: The term distributed leadership is now widely used among scholars and practitioners in the field of educational leadership. Major actors in the nonprofit sector promote and financially support the development of distributed leadership. Unfortunately, there is confusion and ambiguity about what distributed leadership means, and there is no strong link between distributed leadership and two primary goals of the educational leadership field: school improvement and leadership development. Purpose: The author inventories usages of distributed leadership and exposes some of the key fault lines between these meanings and the implicit disagreements that underlie them. The author's objective in this exercise is to catalyze discussions about how to keep research around distributed leadership both theoretically anchored and connected to problems of practice central to the field. Findings: There are four common usages of the term distributed leadership , which include the original descriptive theoretical lens and three prescriptions for how sharing leadership in schools can improve practice. Each usage has its strengths and weaknesses, though two of the prescriptive usages are actually contradicted by empirical research. Conclusions: While not dismissing any particular definition, the author encourages those who use the descriptive definition to focus more on making connections to school improvement and leadership development. The author also encourages those who use the prescriptive definitions to use theoretically and empirically grounded research frames and offers suggestions about how to link research on distributed leadership to the practical concerns of the field.
Managing Conflict in School Teams: The Impact of Task and Goal Interdependence on Conflict Management and Team Effectiveness
Authors: Somech Anit 
Published: July 2008

Purpose: Although conflict has traditionally been considered destructive, recent studies have indicated that conflict management can contribute to effective teamwork. The present study explores conflict management as a team phenomenon in schools. The author examined how the contextual variables (task interdependence, goal interdependence) are related to team conflict management style (integrating vs. dominating) and school team effectiveness (team performance). Research Design: Data were collected from 149 school teams (including team coordinators and team members) at 149 elementary schools. Results: Hierarchical regression analyses demonstrate, as expected, a positive relation between conflict management of integrating and team performance and a negative relation between dominating and team performance. In addition, there are positive relations between the congruent low-low or high-high combinations of task and goal interdependence and integrating and positive relations between the incongruent low-high or high-low combinations of task and goal interdependence and team conflict management of dominating. Moreover, results indicate that the highest level of integrating is under the condition of high task interdependence and high goal interdependence, whereas the highest level of dominating is under the condition of high task interdependence and low goal interdependence. Finally, a team's conflict management was partially mediated by the combination of task and goal interdependence and team performance. Conclusions: The present results provide additional empirical support for the notion that conflict management can be considered a team phenomenon. The study should serve to encourage educational administration researchers to focus more attention on characteristics of organizational and team context as related to team conflict management and team effectiveness.
Districts as Institutional Actors in Educational Reform
Authors: Rorrer Andrea K. , Skrla Linda , Scheurich James Joseph 
Published: July 2008

Purpose: Intermittent attention to the district as the unit of study has left a void in our understanding of the complexities associated with the ability of district-level leaders to contribute to successful, systemic educational reform. In this article, the authors address this void by providing a narrative synthesis of previous findings, proposing a theory of districts as institutional actors in systemic reform with the goal being to increase achievement and advance equity, and suggesting areas of future research that extend our understanding of districts as institutional actors in educational reform and build our knowledge of reform that improves achievement and advances equity. Proposed Conceptual Argument: The four roles of districts evident in research to date are (a) providing instructional leadership, (b) reorienting the organization, (c) establishing policy coherence, and (d) maintaining an equity focus. These four roles, which are interdependent, variably coupled, and coevolving through a nonlinear process, serve as a foundation for the authors' proposed framework of districts as institutional actors in improving achievement and advancing equity. Implications for Research and Practice: The discontinuous and limited nature of previous research has contributed to the lack of theoretical advancement with regard to a research-based understanding of district reform and thus to a lack of research-based guidance for district leaders to follow to create systemically districts that improve achievement and advance educational equity for all children. The framework presented here contributes toward the resolution of these issues by developing an intentional, coherent, and integrated framework of districts as institutional actors in reform.
The Epidemiology of United States High School Soccer Injuries, 2005–2007
Authors: Yard Ellen E. , Schroeder Matthew J. , Fields Sarah K. , Collins Christy L. , Comstock R. Dawn 
Published: July 2008

Background United States high school soccer participation increased 5 fold over the last 30 years. With increased participation comes increased injury incidence. Hypothesis High school soccer injury patterns will vary by gender and type of exposure. Study Design Descriptive epidemiologic study. Methods Soccer-related injury data were collected over the 2005–2006 and 2006–2007 school years from 100 nationally representative United States high schools via Reporting Information Online (RIO, an Internet-based sports-related injury surveillance system). Results Participating certified athletic trainers reported 1524 soccer injuries during 637 446 athlete exposures (AEs), for an injury rate of 2.39 per 1000 AEs, corresponding to a nationally estimated 807 492 soccer-related injuries during the 2005–2006 and 2006–2007 seasons. The injury rate per 1000 AEs was greater during competition (4.77) than practice (1.37) (rate ratio [RR] = 3.49; 95% confidence interval [CI], 3.15–3.87). Overall, the most frequent diagnoses were incomplete ligament sprains (26.8%), incomplete muscle strains (17.9%), contusions (13.8%), and concussions (10.8%). The most commonly injured body sites were the ankle (23.4%), knee (18.7%), head/face (13.7%), and thigh/upper leg (13.1%). Similar proportions of boys (57.9%) and girls (53.9%) returned to activity in <1 week. During competition, girls sustained complete knee ligament sprains requiring surgery at a rate of 26.4 per 100 000 AEs, higher than the rate among boys during competition (1.98 per 100 000 AEs) (RR = 13.3; 95% CI, 3.15–56.35) and among girls during practice (2.34 per 100 000 AEs) (RR = 11.3; 95% CI, 4.31–29.58). Player-to-player contact was more common among competition injuries (injury proportion ratio [IPR] = 2.42; 95% CI, 2.01–2.92), while noncontact mechanisms were more common among practice injuries (IPR = 2.39; 95% CI, 1.90–3.01). Conclusions High school soccer injury patterns vary by gender and type of exposure. Identifying such differences in injury patterns is the important first step in the development of evidence-based, targeted injury prevention efforts.
Crystal structure and crystal chemistry of fluorannite and its relationships
to annite
Authors: Brigatti M. F. , Caprilli E. , Malferrari D. , Mottana A. 
Published: July 2008

Abstract
This study focuses on the crystal-chemical characterization of fluorannite
from the Katugin Ta-Nb deposit, Chitinskaya Oblast’, Kalar Range, Transbaikalia,
eastern Siberia, Russia. The chemical formula of this mineral is
(K0.960Na0.020Ba0.001)(Fe2+2.102Fe3+0.425Cr3+0.002Mg0.039Li0.085Ti0.210Mn0.057)(Al0.674Si3.326)
O10(F1.060OH0.028O0.912).
This mica belongs to the 1M polytype (space group C2/m) with layer parameters a =
5.3454(2) Å, b = 9.2607(4) Å, c = 10.2040(5) Å, b = 100.169(3)º. Structure
refinement, using anisotropic displacement parameters, converged at R = 0.0384.
When compared to annite, fluorannite shows a smaller cell volume
(Vfluorannite = 497.19 Å3;
Vannite = 505.71 Å3), because of its
smaller lateral dimensions and c parameter. Flattening in the plane of the
tetrahedral basal oxygen atoms decreases with F content, together with the A–O4
distance (i.e. the distance between interlayer cation A and the octahedral anionic
position) due to the reduced repulsion between the interlayer cation and the anion
sited in O4.
Overexpression of B cell–activating factor of TNF family (BAFF) is associated with Helicobacter pylori–independent growth of gastric diffuse large B-cell lymphoma with histologic evidence of MALT lymphoma
Authors: Kuo Sung-Hsin , Yeh Pei-Yen , Chen Li-Tzong , Wu Ming-Shiang , Lin Chung-Wu , Yeh Kun-Huei , Tzeng Yi-Shin , Chen Jing-Yi , Hsu Ping-Ning , Lin Jaw-Town , Cheng Ann-Lii 
Published: July 2008

Abstract
We have recently demonstrated that nuclear expression of BCL10 predicts Helicobacter pylori (HP) independence of early-stage gastric diffuse large B-cell lymphoma (DLBCL) with histologic evidence of mucosa-associated lymphoid tissue (MALT). In this study, we examined the role of B cell–activating factor of TNF family (BAFF) in mediating BCL10 nuclear translocation and HP independence of gastric DLBCL (MALT). We used immunohistochemistry and immunoblotting to measure the expression of BAFF, pAKT, BCL3, BCL10, and NF-κB. Transactivity of NF-κB was measured by electromobility shift assay. In lymphoma samples from 26 patients with gastric DLBCL (MALT), we detected aberrant expression of BAFF in 7 of 10 (70%) HP-independent and in 3 of 16 (18.8%) HP-dependent cases (P = .015). BAFF overexpression was associated with pAKT expression (P = .032), and nuclear expression of BCL3 (P = .014), BCL10 (P = .015), and NF-κB (P = .004). In B-cell lymphoma Pfeiffer cells, BAFF activated NF-κB and AKT; the activated NF-κB up-regulated BCL10, and the activated AKT caused formation of BCL10/BCL3 complexes that translocated to the nucleus. Inhibition of AKT by LY294002 (a PI3K inhibitor) blocked BCL10 nuclear translocation, NF-κB transactivity, and BAFF expression. Our results indicate that autocrine BAFF signal transduction pathways may contribute to HP-independent growth of gastric DLBCL (MALT).
Tissue-type plasminogen activator and the low-density lipoprotein receptor–related protein induce Akt phosphorylation in the ischemic brain
Authors: An Jie , Zhang Chen , Polavarapu Rohini , Zhang Xiaohui , Zhang Xiumei , Yepes Manuel 
Published: July 2008

AbstractTissue-type plasminogen activator (tPA) is found in the intravascular space and in the central nervous system. The low-density lipoprotein receptor–related protein (LRP) is expressed in neurons and in perivascular astrocytes. During cerebral ischemia, tPA induces the shedding of LRP's extracellular domain from perivascular astrocytes, and this is followed by the development of cerebral edema. Protein kinase B (Akt) is a serine/threonine kinase that plays a critical role not only in cell survival but also in the regulation of the permeability of the blood-brain barrier. We found that, in the early phases of the ischemic insult, the interaction between tPA and LRP induces Akt phosphorylation (pAkt) in perivascular astrocytes and inhibits pAkt in neurons. Coimmunoprecipitation studies indicate that pAkt and LRP's intracellular domain interact in perivascular astrocytes and that this interaction is dependent on the presence of tPA and results in the development of edema. Together, these results indicate that, in the early stages of cerebral ischemia, the interaction between tPA and LRP in perivascular astrocytes induces the activation of a cell signaling event mediated by pAkt that leads to increase in the permeability of the blood-brain barrier.
A role for multidrug resistance protein 4 (MRP4; ABCC4) in human dendritic cell migration
Authors: van de Ven Rieneke , Scheffer George L. , Reurs Anneke W. , Lindenberg Jelle J. , Oerlemans Ruud , Jansen Gerrit , Gillet Jean-Pierre , Glasgow Joel N. , Pereboev Alexander , Curiel David T. , Scheper Rik J. , de Gruijl Tanja D. 
Published: July 2008

AbstractThe capacity of dendritic cells (DCs) to migrate from peripheral organs to lymph nodes (LNs) is important in the initiation of a T cell–mediated immune response. The ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp; ABCB1) and the multidrug resistance protein 1 (MRP1; ABCC1) have been shown to play a role in both human and murine DC migration. Here we show that a more recently discovered family member, MRP4 (ABCC4), is expressed on both epidermal and dermal human skin DCs and contributes to the migratory capacity of DCs. Pharmacological inhibition of MRP4 activity or down-regulation through RNAi in DCs resulted in reduced migration of DCs from human skin explants and of in vitro generated Langerhans cells. The responsible MRP4 substrate remains to be identified as exogenous addition of MRP4's known substrates prostaglandin E2, leukotriene B4 and D4, or cyclic nucleotides (all previously implicated in DC migration) could not restore migration. This notwithstanding, our data show that MRP4 is an important protein, significantly contributing to human DC migration toward the draining lymph nodes, and therefore relevant for the initiation of an immune response and a possible target for immunotherapy.
Graft rejection as a Th1-type process amenable to regulation by donor Th2-type cells through an interleukin-4/STAT6 pathway
Authors: Mariotti Jacopo , Foley Jason , Ryan Kaitlyn , Buxhoeveden Nicole , Kapoor Veena , Amarnath Shoba , Fowler Daniel H. 
Published: July 2008

AbstractGraft rejection has been defined as the mirror image of graft-versus-host disease, which is biologically characterized primarily as a Th1-type process. As such, we reasoned that graft rejection would represent a Th1 response amenable to Th2 modulation. Indeed, adoptive transfer of host Th1-type cells mediated rejection of fully MHC-disparate murine bone marrow allografts more effectively than host Th2-type cells. Furthermore, STAT1-deficient host T cells did not differentiate into Th1-type cells in vivo and failed to mediate rejection. We next hypothesized that donor Th2 cell allograft augmentation would prevent rejection by modulation of the host Th1/Th2 balance. In the setting of donor Th2 cell therapy, host–anti-donor allospecific T cells acquired Th2 polarity, persisted posttransplantation, and did not mediate rejection. Abrogation of rejection required donor Th2 cell IL-4 secretion and host T-cell STAT6 signaling. In conclusion, T cell–mediated marrow graft rejection primarily resembles a Th1-type process that can be abrogated by donor Th2 cell therapy that promotes engraftment through a novel mechanism whereby cytokine polarization is transferred to host T cells.
Accelerated exchange of exon segments in Viperid three-finger toxin genes (Sistrurus catenatus edwardsii; Desert Massasauga)
Authors: Doley Robin , Pahari Susanta , Mackessy Stephen P , Kini R Manjunatha 
Published: July 2008

AbstractBackgroundSnake venoms consist primarily of proteins and peptides showing a myriad of potent biological activities which have been shaped by both adaptive and neutral selective forces. Venom proteins are encoded by multigene families that have evolved through a process of gene duplication followed by accelerated evolution in the protein coding region.ResultsHere we report five gene structures of three-finger toxins from a viperid snake,Sistrurus catenatus edwardsii. These toxin genes are structured similarly to elapid and hydrophiid three-finger toxin genes, with two introns and three exons. Both introns and exons show distinct patterns of segmentation, and the insertion/deletion of segments may define their evolutionary history. The segments in introns, when present, are highly similar to their corresponding segments in other members of the gene family. In contrast, some segments in the exons show high similarity, while others are often distinctly different among corresponding regions of the isoforms.ConclusionOrdered, conserved exon structure strongly suggests that segments in corresponding regions in exons have been exchanged with distinctly different ones during the evolution of these genes. Such a "switching" of segments in exons may result in drastically altering the molecular surface topology and charge, and hence the molecular targets of these three-finger toxins. Thus the phenomenon ofacceleratedsegmentswitch inexons to altertargeting (ASSET) may play an important role in the evolution of three-finger toxins, resulting in a family of toxins with a highly conserved structural fold but widely varying biological activities.
Complex population genetic and demographic history of the Salangid, Neosalanx taihuensis, based on cytochrome b sequences
Authors: Zhao Liang , Zhang Jie , Liu Zhijin , Funk Stephan M , Wei Fuwen , Xu Muqi , Li Ming 
Published: July 2008

AbstractBackgroundThe Salangid icefishNeosalanx taihuensis(Salangidae) is an economically important fish, which is endemic to China, restricted to large freshwater systems (e.g. lakes, large rivers and estuaries) and typically exhibit low vagility. The continuous distribution ranges from the temperate region of the Huai and Yellow River basins to the subtropical region of the Pearl River basin. This wide ranging distribution makes the species an ideal model for the study of palaeoclimatic effects on population genetic structure and phylogeography. Here, we aim to analyze population genetic differentiation within and between river basins and demographic history in order to understand how this species responded to severe climatic oscillations, decline of the sea levels during the Pleistocene ice ages and tectonic activity.ResultsWe obtained the complete mtDNA cytochromebsequences (1141 bp) of 354 individuals from 13 populations in the Pearl River, the Yangze River and the Huai River basin. Thirty-six haplotypes were detected. Haplotype frequency distributions were strongly skewed, with most haplotypes (n = 24) represented only in single samples each and thus restricted to a single population. The most common haplotype (H36) was found in 49.15% of all individuals. Analysis of molecular variance (AMOVA) revealed a random pattern in the distribution of genetic diversity, which is inconsistent with contemporary hydrological structure. Significant levels of genetic subdivision were detected among populations within basins rather than between the three basins. Demographic analysis revealed that the population size in the Pearl River basin has remained relatively constant whereas the populations in the Yangze River and the Huai River basins expanded about 221 and 190 kyr ago, respectively, with the majority of mutations occurring after the last glacial maximum (LGM).ConclusionThe observed complex genetic pattern ofN. taihuensisis coherent with a scenario of multiple unrelated founding events by long-distance colonization and dispersal combined with contiguous population expansion and locally restricted gene flow. We also found that this species was likely severely impacted by past glaciations. More favourable climate and the formation of large suitable habitations together facilitated population expansion after the late Quaternary (especially the LGM). We proposed that all populations should be managed and conserved separately, especially for habitat protection.
Molecular phylogeny of diplomonads and enteromonads based on SSU rRNA, alpha-tubulin and HSP90 genes: Implications for the evolutionary history of the double karyomastigont of diplomonads
Authors: Kolisko Martin , Cepicka Ivan , Hampl Vladimir , Leigh Jessica , Roger Andrew J , Kulda Jaroslav , Simpson Alastair GB , Flegr Jaroslav 
Published: July 2008

Abstract

Background
Fornicata is a relatively recently established group of protists that includes the diplokaryotic diplomonads (which have two similar nuclei per cell), and the monokaryotic enteromonads, retortamonads and Carpediemonas, with the more typical one nucleus per cell. The monophyly of the group was confirmed by molecular phylogenetic studies, but neither the internal phylogeny nor its position on the eukaryotic tree has been clearly resolved.

Results
Here we have introduced data for three genes (SSU rRNA, α-tubulin and HSP90) with a wide taxonomic sampling of Fornicata, including ten isolates of enteromonads, representing the genera Trimitus and Enteromonas, and a new undescribed enteromonad genus. The diplomonad sequences formed two main clades in individual gene and combined gene analyses, with Giardia (and Octomitus) on one side of the basal divergence and Spironucleus, Hexamita and Trepomonas on the other. Contrary to earlier evolutionary scenarios, none of the studied enteromonads appeared basal to diplokaryotic diplomonads. Instead, the enteromonad isolates were all robustly situated within the second of the two diplomonad clades. Furthermore, our analyses suggested that enteromonads do not constitute a monophyletic group, and enteromonad monophyly was statistically rejected in 'approximately unbiased' tests of the combined gene data.

Conclusion
We suggest that all higher taxa intended to unite multiple enteromonad genera be abandoned, that Trimitus and Enteromonas be considered as part of Hexamitinae, and that the term 'enteromonads' be used in a strictly utilitarian sense. Our result suggests either that the diplokaryotic condition characteristic of diplomonads arose several times independently, or that the monokaryotic cell of enteromonads originated several times independently by secondary reduction from the diplokaryotic state. Both scenarios are evolutionarily complex. More comparative data on the similarity of the genomes of the two nuclei of diplomonads will be necessary to resolve which evolutionary scenario is more probable.