2,028 research outputs found
School-Based Leadership Perspectives on University Partnerships
The success of school-university partnerships depends on the leadership. This qualitative study reports on school-based leaders (SBAs) as critical stakeholders in the collaborative process of forming viable partnerships with colleges and universities. It describes SBAs’ responsibilities as partners, motivation for forming their partnerships, perceived benefits and challenges of the partnership, perspectives on forming and sustaining a partnership, and self-reflective comments about their leadership characteristics as an SBA and a partner. Sixteen SBAs, most of whom were school principals, responded to 12 interview questions. SBAs indicated that they have been engaged with Professional Development Schools (PDSs) an average of 10 years. They pursued their partnerships with colleges and universities to help their students, teachers, and schools. Even with the additional responsibilities and any challenges encountered, SBAs found that PDSs provided additional resources and support, collaboration, and opportunities to impact future teachers. SBAs believed that they had the necessary leadership qualities for developing PDSs as vehicles for promoting the profession. They saw themselves as collaborative, visionary, dedicated, organized, striving for excellence, motivational, and supportive. Ideas are presented for creating a leadership profile of SBAs involved in PDSs to establish guidelines for their optimum roles and responsibilities in partnership work
University Leadership of Professional Development Schools
This study investigated the roles and responsibilities of University-Based Administrators (UBAs) in relation to their oversight of Professional Development Schools PDSs. UBAs refer to college administrators such as department chairs, program coordinators, directors, assistant deans, associate deans, and deans. The participants were 36 UBAs ranging from mid-level administrators to faculty chairpersons. They represented universities of various sizes and Carnegie classifications from across the United States. The UBAs responded through email or by telephone to nine semi-structured interview questions related to their PDS work. The majority of UBAs were tenure-track or clinical faculty, who spent less than 50% of their time on PDS work. Forty-six percent of the UBAs’ Institutions of Higher Education (IHEs) partnered with between one to ten PDSs. The majority of the IHEs had been doing PDS work for 11-19 years. Findings revealed significant variation in UBA’s roles and responsibilities. There is no standardized leadership title, set of responsibilities or qualifications, or structure for the oversight of PDS activities and networks. Three major administrative responsibilities related to PDS work emerged: personnel, programs, and documents. UBAs reported the greatest challenges were time, sustainability, resources/support
Observations of solar wind ion charge exchange in the comet Halley coma
Giotto Ion Mass Spectrometer/High Energy Range Spectrometer (IMS/HERS) observations of solar wind ions show charge exchange effects and solar wind compositional changes in the coma of comet Halley. As the comet was approached, the He(++) to proton density ratio increased until about 1 hour before closest approach after which time it decreased. Abrupt increases in this ratio were also observed in the beginning and near the end of the so-called Mystery Region (8.6 - 5.5(10)(exp 5) km from the comet along the spacecraft trajectory). These abrupt increases in the density ratio were well correlated with enhanced fluxes of keV electrons as measured by the Giotto plasma electron spectrometer. The general increase and then decrease of the He(++) to proton density ratio is quantitatively consistent with a combination of the addition of protons of cometary origin to the plasma and loss of plasma through charge exchange of protons and He(++). In general agreement with the solar wind proton and He(++) observations, solar wind oxygen and carbon ions were observed to charge exchange from higher to lower charge states with decreasing distance to the comet. The more abrupt increases in the He(++) to proton and the He(++) to O(6+) density ratios in the mystery region require a change in the solar wind ion composition in this region while the correlation with energetic electrons indicates processes associated with the comet
Observations of plasma dynamics in the coma of P/Halley by the Giotto Ion Mass Spectrometer
Observations in the coma of P/Halley by the Giotto Ion Mass Spectrometer (IMS) are reported. The High Energy Range Spectrometer (HERS) of the IMS obtained measurements of protons and alpha particles from the far upstream region to the near ionopause region and of ions from mass 12 to 32 at distances of about 250,000 to 40,000 km from the nucleus. Plasma parameters from the High Intensity Spectrometer (HIS) of the IMS obtained between 150,000 to 5000 km from the nucleus are also discussed. The distribution functions of water group ions (water group will be used to refer to ions of 16 to 18 m/q, where m is in AMU and q is in unit charges) are observed to be spherically symmetric in velocity space, indicating strong pitch angle scattering. The discontinuity known as the magnetic pile-up boundary (MPB) is apparent only in proton, alpha, and magnetometer data, indicating that it is a tangential discontinuity of solar wind origin. HERS observations show no significant change in the properties of the heavy ions across the MPB. A comparison of the observations to an MHD model is made. The plasma flow directions at all distances greater than 30,000 km from the nucleus are in agreement with MHD calculations. However, despite the agreement in flow direction, within 200,000 km of the nucleus the magnitude of the velocity is lower than predicted by the MHD model and the density is much larger (a factor of 4). Within 30,000 km of the nucleus there are large theoretical differences between the MHD model flow calculations for the plane containing the magnetic field and for the plane perpendicular to the magnetic field. The observations agreed much better with the pattern calculated for the plane perpendicular to the magnetic field. The data obtained by the High Energy Range Spectrometer (HERS) of the IMS that are published herein were provided to the International Halley Watch archive
Regulators of G-Protein signaling RGS10 and RGS17 regulate chemoresistance in ovarian cancer cells
<p>Abstract</p> <p>Background</p> <p>A critical therapeutic challenge in epithelial ovarian carcinoma is the development of chemoresistance among tumor cells following exposure to first line chemotherapeutics. The molecular and genetic changes that drive the development of chemoresistance are unknown, and this lack of mechanistic insight is a major obstacle in preventing and predicting the occurrence of refractory disease. We have recently shown that Regulators of G-protein Signaling (RGS) proteins negatively regulate signaling by lysophosphatidic acid (LPA), a growth factor elevated in malignant ascites fluid that triggers oncogenic growth and survival signaling in ovarian cancer cells. The goal of this study was to determine the role of RGS protein expression in ovarian cancer chemoresistance.</p> <p>Results</p> <p>In this study, we find that RGS2, RGS5, RGS10 and RGS17 transcripts are expressed at significantly lower levels in cells resistant to chemotherapy compared with parental, chemo-sensitive cells in gene expression datasets of multiple models of chemoresistance. Further, exposure of SKOV-3 cells to cytotoxic chemotherapy causes acute, persistent downregulation of RGS10 and RGS17 transcript expression. Direct inhibition of RGS10 or RGS17 expression using siRNA knock-down significantly reduces chemotherapy-induced cell toxicity. The effects of cisplatin, vincristine, and docetaxel are inhibited following RGS10 and RGS17 knock-down in cell viability assays and phosphatidyl serine externalization assays in SKOV-3 cells and MDR-HeyA8 cells. We further show that AKT activation is higher following RGS10 knock-down and RGS 10 and RGS17 overexpression blocked LPA mediated activation of AKT, suggesting that RGS proteins may blunt AKT survival pathways.</p> <p>Conclusions</p> <p>Taken together, our data suggest that chemotherapy exposure triggers loss of RGS10 and RGS17 expression in ovarian cancer cells, and that loss of expression contributes to the development of chemoresistance, possibly through amplification of endogenous AKT signals. Our results establish RGS10 and RGS17 as novel regulators of cell survival and chemoresistance in ovarian cancer cells and suggest that their reduced expression may be diagnostic of chemoresistance.</p
Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology
<p>Abstract</p> <p>Background</p> <p>Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP) cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development.</p> <p>Results</p> <p>Our results demonstrate that Lysophosphatidic Acid (LPA) and Sphingosine-1-phosphate (S1P) receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to G<sub>i/o </sub>G-proteins that inhibit adenylyl cyclase and to G<sub>q</sub>-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via G<sub>i/o </sub>coupled receptors in an Epidermal Growth Factor Receptor (EGFR)- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK.</p> <p>Conclusion</p> <p>Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors.</p
Crystal structures and freezing of dipolar fluids
We investigate the crystal structure of classical systems of spherical
particles with an embedded point dipole at T=0. The ferroelectric ground state
energy is calculated using generalizations of the Ewald summation technique.
Due to the reduced symmetry compared to the nonpolar case the crystals are
never strictly cubic. For the Stockmayer (i.e., Lennard-Jones plus dipolar)
interaction three phases are found upon increasing the dipole moment:
hexagonal, body-centered orthorhombic, and body-centered tetragonal. An even
richer phase diagram arises for dipolar soft spheres with a purely repulsive
inverse power law potential . A crossover between qualitatively
different sequences of phases occurs near the exponent . The results are
applicable to electro- and magnetorheological fluids. In addition to the exact
ground state analysis we study freezing of the Stockmayer fluid by
density-functional theory.Comment: submitted to Phys. Rev.
Magnetization of ferrofluids with dipolar interactions - a Born--Mayer expansion
For ferrofluids that are described by a system of hard spheres interacting
via dipolar forces we evaluate the magnetization as a function of the internal
magnetic field with a Born--Mayer technique and an expansion in the dipolar
coupling strength. Two different approximations are presented for the
magnetization considering different contributions to a series expansion in
terms of the volume fraction of the particles and the dipolar coupling
strength.Comment: 19 pages, 11 figures submitted to PR
Chemistry and the Science of Transformation in Mary Shelley’s Frankenstein
This essay reads the novel in a new way, examining the way that Victor Frankenstein's chemical education (he does not train to be a doctor!) enables his creation of the monster. It reveals that chemists of the period had a different worldview to others where they saw the world in constant transformation and flux. I have written this essay co-written the introduction to the special issue, and co-edited the whole
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