Ponticulin is the major high affinity link between the plasma membrane and the cortical actin network in Dictyostelium

Interactions between the plasma membrane and underlying actin-based cortex have been implicated in membrane organization and stability, the control of cell shape, and various motile processes. To ascertain the function of high affinity actin-membrane associations, we have disrupted by homologous recombination the gene encoding ponticulin, the major high affinity actin-membrane link in Dictyostelium discoideum amoebae. Cells lacking detectable amounts of ponticulin message and protein also are deficient in high affinity actin-membrane binding by several criteria. First, only 10-13% as much endogenous actin cosediments through sucrose and crude plasma membranes from ponticulin-minus cells, as compared with membranes from the parental strain. Second, purified plasma membranes exhibit little or no binding or nucleation of exogenous actin in vitro. Finally, only 10-30% as much endogenous actin partitions with plasma membranes from ponticulin-minus cells after these cells are mechanically unroofed with polylysine-coated coverslips. The loss of the cell\u27s major actin-binding membrane protein appears to be surprisingly benign under laboratory conditions. Ponticulin-minus cells grow normally in axenic culture and pinocytose FITC-dextran at the same rate as do parental cells. The rate of phagocytosis of particles by ponticulin-minus cells in growth media also is unaffected. By contrast, after initiation of development, cells lacking ponticulin aggregate faster than the parental cells. Subsequent morphogenesis proceeds asynchronously, but viable spores can form. These results indicate that ponticulin is not required for cellular translocation, but apparently plays a role in cell patterning during development

A Rating Scale for the Measurement of Teacher Readiness for the Role of Administrative Leadership

This study has a twofold purpose. The first is to demonstrate the use of the Forced-Choice Technique in developing a rating scale for the selection of teachers adjudged to be ready to assume responsibility of an administrative nature and a role of leadership. The second is to develop a tentative rating scale for this purpose in the Dallas Independent School District, Dallas, Texas

Effectiveness evaluation of STOL transport operations

A short-takeoff and landing (STOL) systems simulation model has been developed and implemented in a computer code (known as STOL OPS) which permits evaluation of the operation of a STOL aircraft and its avionics in a commercial airline operating environment. STOL OPS concentrated on the avionics functions of navigation, guidance, control, communication, hazard aviodance, and systems management. External world factors influencing the operation of the STOL aircraft include each airport and its geometry, air traffic at each airport, air traffic control equipment and procedures, weather (including winds and visibility), and the flight path between each airport served by the route. The development of the STOL OPS program provides NASA a set of computer programs which can be used for detailed analysis of a STOL aircraft and its avionics and permit establishment of system requirements as a function of airline mission performance goals

Usability / Accessibility Protocols

Curatorial note from Digital Pedagogy in the Humanities: This assignment for an undergraduate course asks students to go beyond evaluating digital content with criteria provided by someone else. Here, they must develop their own “collection of customized usability and accessibility testing steps and procedures,” or “protocols,” to be used for such evaluation. Allison Hitt asks students to consult Steve Krug’s Don’t Make Me Think, Revisited when creating their usability testing protocol and the Web Content Accessibility Guidelines from the World Wide Web Consortium when creating their accessibility testing protocol. As a result, Hitt requires students to think critically about the impact of design choices that go into creating digital content as well as the technical standards that govern such content’s code and markup

Pattern formation driven by nematic ordering of assembling biopolymers

The biopolymers actin and microtubules are often in an ongoing assembling/disassembling state far from thermal equilibrium. Above a critical density this leads to spatially periodic patterns, as shown by a scaling argument and in terms of a phenomenological continuum model, that meets also Onsager's statistical theory of the nematic--to--isotropic transition in the absence of reaction kinetics. This pattern forming process depends much on nonlinear effects and a common linear stability analysis of the isotropic distribution of the filaments is often misleading. The wave number of the pattern decreases with the assembling/disassembling rate and there is an uncommon discontinuous transition between the nematic and the periodic state.Comment: 4 pages, 3 figure

Targeting Nucleotide Biosynthesis: A Strategy for Improving the Oncolytic Potential of DNA Viruses

The rapid growth of tumors depends upon elevated levels of dNTPs, and while dNTP concentrations are tightly regulated in normal cells, this control is often lost in transformed cells. This feature of cancer cells has been used to advantage to develop oncolytic DNA viruses. DNA viruses employ many different mechanisms to increase dNTP levels in infected cells, because the low concentration of dNTPs found in non-cycling cells can inhibit virus replication. By disrupting the virus-encoded gene(s) that normally promote dNTP biosynthesis, one can assemble oncolytic versions of these agents that replicate selectively in cancer cells. This review covers the pathways involved in dNTP production, how they are dysregulated in cancer cells, and the various approaches that have been used to exploit this biology to improve the tumor specificity of oncolytic viruses. In particular, we compare and contrast the ways that the different types of oncolytic virus candidates can directly modulate these processes. We limit our review to the large DNA viruses that naturally encode homologs of the cellular enzymes that catalyze dNTP biogenesis. Lastly, we consider how this knowledge might guide future development of oncolytic viruses

Indirect learning: how emerging-market firms grow in developed markets

Some emerging-market firms have recently achieved substantial growth in developed markets despite having had little prior experience in these markets. What explains the performance of these firms? Building on the organizational learning literature, the authors argue that indirect learning (i.e., learning from the experience of others) plays a crucial role in explaining this phenomenon. Specifically, they propose that emerging-market firms that grow in developed markets overcome their lack of direct experience in such markets by learning indirectly through their leaders, competitors, and interfirm networks. The authors test their thesis by comparing the international growth in developed markets of a sample of emerging-market firms (116 Indian firms) with a sample of developed-market firms (160 U.K. firms). The results support the authors' thesis about the importance of indirect learning in explaining the international growth of emerging-market (relative to developed-market) firms in developed markets. The authors discuss the implications of these findings for policy makers in the areas of higher education, competition policy, and international trade as well as for managers in the areas of middle-management recruitment, competitor analysis and tracking, and managing interfirm networks

CEH-GEAR: 1 km resolution daily and monthly areal rainfall estimates for the UK for hydrological and other applications

The Centre for Ecology & Hydrology – Gridded Estimates of Areal Rainfall (CEH-GEAR) data set was developed to provide reliable 1 km gridded estimates of daily and monthly rainfall for Great Britain (GB) and Northern Ireland (NI) (together with approximately 3500 km2 of catchment in the Republic of Ireland) from 1890 onwards. The data set was primarily required to support hydrological modelling. The rainfall estimates are derived from the Met Office collated historical weather observations for the UK which include a national database of rain gauge observations. The natural neighbour interpolation methodology, including a normalisation step based on average annual rainfall (AAR), was used to generate the daily and monthly rainfall grids. To derive the monthly estimates, rainfall totals from monthly and daily (when complete month available) rain gauges were used in order to obtain maximum information from the rain gauge network. The daily grids were adjusted so that the monthly grids are fully consistent with the daily grids. The CEH-GEAR data set was developed according to the guidance provided by the British Standards Institution. The CEH-GEAR data set contains 1 km grids of daily and monthly rainfall estimates for GB and NI for the period 1890–2012. For each day and month, CEH-GEAR includes a secondary grid of distance to the nearest operational rain gauge. This may be used as an indicator of the quality of the estimates. When this distance is greater than 100 km, the estimates are not calculated due to high uncertainty

Spectroscopy of 13B via the 13C(t,3He) reaction at 115 AMeV

Gamow-Teller and dipole transitions to final states in 13B were studied via the 13C(t,3He) reaction at Et = 115 AMeV. Besides the strong Gamow-Teller transition to the 13B ground state, a weaker Gamow-Teller transition to a state at 3.6 MeV was found. This state was assigned a spin-parity of 3/2- by comparison with shell-model calculations using the WBP and WBT interactions which were modified to allow for mixing between nhw and (n+2)hw configurations. This assignment agrees with a recent result from a lifetime measurement of excited states in 13B. The shell-model calculations also explained the relatively large spectroscopic strength measured for a low-lying 1/2+ state at 4.83 MeV in 13B. The cross sections for dipole transitions up to Ex(13B)= 20 MeV excited via the 13C(t,3He) reaction were also compared with the shell-model calculations. The theoretical cross sections exceeded the data by a factor of about 1.8, which might indicate that the dipole excitations are "quenched". Uncertainties in the reaction calculations complicate that interpretation.Comment: 11 pages, 6 figure

The 150^{150}Nd(3^3He,tt) and 150^{150}Sm(tt,3^3He) reactions with applications to ββ\beta\beta decay of 150^{150}Nd

The $^{150}$Nd($^3$He,$t$) reaction at 140 MeV/u and $^{150}$Sm($t$,$^3$He) reaction at 115 MeV/u were measured, populating excited states in $^{150}$Pm. The transitions studied populate intermediate states of importance for the (neutrinoless) $\beta\beta$ decay of $^{150}$Nd to $^{150}$Sm. Monopole and dipole contributions to the measured excitation-energy spectra were extracted by using multipole decomposition analyses. The experimental results were compared with theoretical calculations obtained within the framework of Quasiparticle Random-Phase Approximation (QRPA), which is one of the main methods employed for estimating the half-life of the neutrinoless $\beta\beta$ decay ($0\nu\beta\beta$) of $^{150}$Nd. The present results thus provide useful information on the neutrino responses for evaluating the $0\nu\beta\beta$ and $2\nu\beta\beta$ matrix elements. The $2\nu\beta\beta$ matrix element calculated from the Gamow-Teller transitions through the lowest $1^{+}$ state in the intermediate nucleus is maximally about half of that deduced from the half-life measured in $2\nu\beta\beta$ direct counting experiments and at least several transitions through $1^{+}$ intermediate states in $^{150}$Pm are required to explain the $2\nu\beta\beta$ half-life. Because Gamow-Teller transitions in the $^{150}$Sm($t$,$^3$He) experiment are strongly Pauli-blocked, the extraction of Gamow-Teller strengths was complicated by the excitation of the $2\hbar\omega$, $\Delta L=0$, $\Delta S=1$ isovector spin-flip giant monopole resonance (IVSGMR). However, the near absence of Gamow-Teller transition strength made it possible to cleanly identify this resonance, and the strength observed is consistent with the full exhaustion of the non-energy-weighted sum rule for the IVSGMR.Comment: 18 pages, 13 figures, 2 table