Telescience Resource Kit Software Lifecycle

The challenge of a global operations capability led to the Telescience Resource Kit (TReK) project, an in-house software development project of the Mission Operations Laboratory (MOL) at NASA's Marshall Space Flight Center (MSFC). The TReK system is being developed as an inexpensive comprehensive personal computer- (PC-) based ground support system that can be used by payload users from their home sites to interact with their payloads on board the International Space Station (ISS). The TReK project is currently using a combination of the spiral lifecycle model and the incremental lifecycle model. As with any software development project, there are four activities that can be very time consuming: Software design and development, project documentation, testing, and umbrella activities, such as quality assurance and configuration management. In order to produce a quality product, it is critical that each of these activities receive the appropriate amount of attention. For TReK, the challenge was to lay out a lifecycle and project plan that provides full support for these activities, is flexible, provides a way to deal with changing risks, can accommodate unknowns, and can respond to changes in the environment quickly. This paper will provide an overview of the TReK lifecycle, a description of the project's environment, and a general overview of project activities

Effective Department Meetings: The right approach varies

This workshop will provide positive and instrumental approaches to meeting planning and management that allow chairs to effectively address challenging situations with confidence. Scenarios where specific meeting dynamics may be implemented to address difficult situations or maximize productivity will be discussed in breakout groups and finally considered by all

Crack initiation and fracture features of Fe–Co–B–Si–Nb bulk metallic glass during compression

The aim of the paper was investigation crack initiation and fracture features developed during compression of Fe-based bulk metallic glass (BMG). These Fe-based BMG has received great attention as a new class of structural material due to an excellent properties (e.g. high strength and high elasticity) and low costs. However, the poor ductility and brittle fracture exhibited in BMGs limit their structural application. At room temperature, BMGs fails catastrophically without appreciable plastic deformation under tension and only very limited plastic deformation is observed under compression or bending. Hence a well understanding of the crack initiation and fracture morphology of Fe-based BMGs after compression is of much importance for designing high performance BMGs. The raw materials used in this experiment for the production of BMGs were pure Fe, Co, Nb metals and nonmetallic elements: Si, B. The Fe–Co–B–Si–Nb alloy was cast as rods with three different diameters. The structure of the investigated BMGs rod is amorphous. The measurement of mechanical properties (Young modulus - E, compressive stress - ?c, elastic strain - ?, unitary elastic strain energy – Uu) were made in compression test. Compression test indicates the rods of Fe-based alloy to exhibit high mechanical strength. The development of crack initiation and fracture morphology after compression of Fe-based BMG were examined with scanning electron microscope (SEM). Fracture morphology of rods has been different on the cross section. Two characteristic features of the compressive fracture morphologies of BMGs were observed. One is the smooth region. Another typical feature of the compressive fracture morphology of BMGs is the vein pattern. The veins on the compressive fracture surface have an obvious direction as result of initial displace of sample along shear bands. This direction follows the direction of the displacement of a material. The formation of veins on the compressive fracture surface is closely related to the shear fracture mechanism. The results of these studies may improve the understanding on the fracture features and mechanisms of BMGs and may provide instructions on future design for ductile BMGs with high resistance for fracture

Structure-based inhibitors of amyloid beta core suggest a common interface with tau.

Alzheimer's disease (AD) pathology is characterized by plaques of amyloid beta (Aβ) and neurofibrillary tangles of tau. Aβ aggregation is thought to occur at early stages of the disease, and ultimately gives way to the formation of tau tangles which track with cognitive decline in humans. Here, we report the crystal structure of an Aβ core segment determined by MicroED and in it, note characteristics of both fibrillar and oligomeric structure. Using this structure, we designed peptide-based inhibitors that reduce Aβ aggregation and toxicity of already-aggregated species. Unexpectedly, we also found that these inhibitors reduce the efficiency of Aβ-mediated tau aggregation, and moreover reduce aggregation and self-seeding of tau fibrils. The ability of these inhibitors to interfere with both Aβ and tau seeds suggests these fibrils share a common epitope, and supports the hypothesis that cross-seeding is one mechanism by which amyloid is linked to tau aggregation and could promote cognitive decline

Structure and soft magnetic properties of Fe72B20Si4Nb4 bulk metallic glasses

Purpose: The paper presents a microstructure characterization, thermal stability and soft magnetic properties analysis of Fe-based bulk amorphous materials. Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 glassy alloy in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The magnetic properties were determined by the Maxwell-Wien bridge and VSM methods. Findings: The X-ray diffraction and transmission electron microscopy investigations have revealed that the studied as-cast bulk metallic glasses were amorphous. Broad diffraction halo can be seen for all tested samples, indicating the formation of a glassy phase with the diameters up to 2 mm. The fracture surface of rod samples appears to consist of small fracture zones, which leads to breaking of the samples into parts. A two stage crystallization process was observed for studied amorphous alloy. The changes of crystallization temperatures and magnetic properties as a function of glassy samples thickness were stated. Practical implications: The studied Fe-based alloy system has good glass-forming ability and thermal stability for casting bulk metallic glasses, which exhibit good soft magnetic properties, useful for many electric and magnetic applications. Originality/value: The obtained examination results confirm the utility of applied investigation methods in the microstructure, thermal and soft magnetic properties analysis of examined bulk amorphous alloys

Atomic structures of fibrillar segments of hIAPP suggest tightly mated β-sheets are important for cytotoxicity.

hIAPP fibrils are associated with Type-II Diabetes, but the link of hIAPP structure to islet cell death remains elusive. Here we observe that hIAPP fibrils are cytotoxic to cultured pancreatic β-cells, leading us to determine the structure and cytotoxicity of protein segments composing the amyloid spine of hIAPP. Using the cryoEM method MicroED, we discover that one segment, 19-29 S20G, forms pairs of β-sheets mated by a dry interface that share structural features with and are similarly cytotoxic to full-length hIAPP fibrils. In contrast, a second segment, 15-25 WT, forms non-toxic labile β-sheets. These segments possess different structures and cytotoxic effects, however, both can seed full-length hIAPP, and cause hIAPP to take on the cytotoxic and structural features of that segment. These results suggest that protein segment structures represent polymorphs of their parent protein and that segment 19-29 S20G may serve as a model for the toxic spine of hIAPP

Exact Thermodynamics of the Double sinh-Gordon Theory in 1+1-Dimensions

We study the classical thermodynamics of a 1+1-dimensional double-well sinh-Gordon theory. Remarkably, the Schrodinger-like equation resulting from the transfer integral method is quasi-exactly solvable at several temperatures. This allows exact calculation of the partition function and some correlation functions above and below the short-range order (``kink'') transition, in striking agreement with high resolution Langevin simulations. Interesting connections with the Landau-Ginzburg and double sine-Gordon models are also established.Comment: 4 pages, 3 figures (embedded using epsf), uses RevTeX plus macro (included). Minor revision to match journal version, Phys. Rev. Lett. (in press

Noise-Induced Phase Space Transport in Two-Dimensional Hamiltonian Systems

First passage time experiments were used to explore the effects of low amplitude noise as a source of accelerated phase space diffusion in two-dimensional Hamiltonian systems, and these effects were then compared with the effects of periodic driving. The objective was to quantify and understand the manner in which ``sticky'' chaotic orbits that, in the absence of perturbations, are confined near regular islands for very long times, can become ``unstuck'' much more quickly when subjected to even very weak perturbations. For both noise and periodic driving, the typical escape time scales logarithmically with the amplitude of the perturbation. For white noise, the details seem unimportant: Additive and multiplicative noise typically have very similar effects, and the presence or absence of a friction related to the noise by a Fluctuation-Dissipation Theorem is also largely irrelevant. Allowing for colored noise can significantly decrease the efficacy of the perturbation, but only when the autocorrelation time becomes so large that there is little power at frequencies comparable to the natural frequencies of the unperturbed orbit. Similarly, periodic driving is relatively inefficient when the driving frequency is not comparable to these natural frequencies. This suggests strongly that noise-induced extrinsic diffusion, like modulational diffusion associated with periodic driving, is a resonance phenomenon. The logarithmic dependence of the escape time on amplitude reflects the fact that the time required for perturbed and unperturbed orbits to diverge a given distance scales logarithmically in the amplitude of the perturbation.Comment: 15 pages, including 13 Figures and 1 Table, uses Phys. Rev. macro

Regulation of cell survival by sphingosine-1-phosphate receptor S1P1 via reciprocal ERK-dependent suppression of bim and PI-3-kinase/protein kinase C-mediated upregulation of Mcl-1

Although the ability of bioactive lipid sphingosine-1-phosphate (S1P) to positively regulate anti-apoptotic/pro-survival responses by binding to S1P1 is well known, the molecular mechanisms remain unclear. Here we demonstrate that expression of S1P1 renders CCL39 lung fibroblasts resistant to apoptosis following growth factor withdrawal. Resistance to apoptosis was associated with attenuated accumulation of pro-apoptotic BH3-only protein Bim. However, although blockade of extracellular signal-regulated kinase (ERK) activation could reverse S1P1-mediated suppression of Bim accumulation, inhibition of caspase-3 cleavage was unaffected. Instead S1P1-mediated inhibition of caspase-3 cleavage was reversed by inhibition of phosphatidylinositol-3-kinase (PI3K) and protein kinase C (PKC), which had no effect on S1P1 regulation of Bim. However, S1P1 suppression of caspase-3 was associated with increased expression of anti-apoptotic protein Mcl-1, the expression of which was also reduced by inhibition of PI3K and PKC. A role for the induction of Mcl-1 in regulating endogenous S1P receptor-dependent pro-survival responses in human umbilical vein endothelial cells was confirmed using S1P receptor agonist FTY720-phosphate (FTY720P). FTY720P induced a transient accumulation of Mcl-1 that was associated with a delayed onset of caspase-3 cleavage following growth factor withdrawal, whereas Mcl-1 knockdown was sufficient to enhance caspase-3 cleavage even in the presence of FTY720P. Consistent with a pro-survival role of S1P1 in disease, analysis of tissue microarrays from ER+ breast cancer patients revealed a significant correlation between S1P1 expression and tumour cell survival. In these tumours, S1P1 expression and cancer cell survival were correlated with increased activation of ERK, but not the PI3K/PKB pathway. In summary, pro-survival/anti-apoptotic signalling from S1P1 is intimately linked to its ability to promote the accumulation of pro-survival protein Mcl-1 and downregulation of pro-apoptotic BH3-only protein Bim via distinct signalling pathways. However, the functional importance of each pathway is dependent on the specific cellular context

Explorations, Vol. 4, No. 1

Articles include: Cover: Old Yarmouth Light, 1960, Cape Forchu, Nova Scotia. By and from the collection of Edgar McKay. The Borderlands Concept: a new look at U.S.-Canada relations, by Victor Konrad and Lauren McKensey Fundy Tidal Power Project, by Gregory White Canadian Poet: Ken Norris Native American Life and Art: a celebration, November, 1986, by Lee-Ann Konrad The Montreal Canadiens: a cultural institution, by James J. Herlan U.S. and Canadian Executives: uses of formal and informal plans in top executive decision-making, by Kent Carter Our Cover Artist: bits and pieces of one man\u27s Nova Scotia, by Edgar McKay The Canadian-American Center and the Canadian Collection of the Fogler Library, by Alice Stewart Capitalist Development in the New England-Atlantic Provinces Region, by Robert H. Babcock Atlantic Canadian Members of Parliament as Representatives, by Howard Cody The Rower and the Pyramid: a tribute to Joe Walsh, by Edward D. Ives The Canadian-American Center: exercise in excellence, by Rand Erb Canadian and Maine Potatoes: a bushel of questions, by George K. Griner, Alan S. Kezis, and James D. Leiby After 20: the Future of the Canadian-American Center, by Victor Konra