10,001 research outputs found
Measuring software technology
Results are reported from a series of investigations into the effectiveness of various methods and tools used in a software production environment. The basis for the analysis is a project data base, built through extensive data collection and process instrumentation. The project profiles become an organizational memory, serving as a reference point for an active program of measurement and experimentation on software technology
Managers Handbook for Software Development
Methods and aids for the management of software development projects are presented. The recommendations are based on analyses and experiences with flight dynamics software development. The management aspects of organizing the project, producing a development plan, estimation costs, scheduling, staffing, preparing deliverable documents, using management tools, monitoring the project, conducting reviews, auditing, testing, and certifying are described
N terminus is key to the dominant negative suppression of CaV2 calcium channels: implications for episodic ataxia type 2
Expression of the calcium channels CaV2.1 and CaV2.2 is markedly suppressed by co-expression with truncated constructs containing Domain I. This is the basis for the phenomenon of dominant negative suppression observed for many of the episodic ataxia type 2 mutations in CaV2.1 that predict truncated channels. The process of dominant negative suppression has been shown previously to stem from interaction between the full-length and truncated channels and to result in downstream consequences of the unfolded protein response and endoplasmic reticulum-associated protein degradation. We have now identified the specific domain that triggers this effect. For both CaV2.1 and CaV2.2, the minimum construct producing suppression was the cytoplasmic N terminus. Suppression was enhanced by tethering the N terminus to the membrane with a CAAX motif. The 11-amino acid motif (including Arg52 and Arg54) within the N terminus, which we have previously shown to be required for G protein modulation, is also essential for dominant negative suppression. Suppression is prevented by addition of an N-terminal tag (XFP) to the full-length and truncated constructs. We further show that suppression of CaV2.2 currents by the N terminus-CAAX construct is accompanied by a reduction in CaV2.2 protein level, and this is also prevented by mutation of Arg52 and Arg54 to Ala in the truncated construct. Taken together, our evidence indicates that both the extreme N terminus and the Arg52, Arg54 motif are involved in the processes underlying dominant negative suppression
Complex Instantons and Charged Rotating Black Hole Pair Creation
We consider the general process of pair-creation of charged rotating black
holes. We find that instantons which describe this process are necessarily
complex due to regularity requirements. However their associated probabilities
are real, and fully consistent with the interpretation that the entropy of a
charged rotating black hole is the logarithm of the number of its quantum
states.Comment: 11 pages, 1 figure, Latex, text shortened with only minor changes in
content, accepted for Phys Rev Letter
New broad 8Be nuclear resonances
Energies, total and partial widths, and reduced width amplitudes of 8Be
resonances up to an excitation energy of 26 MeV are extracted from a coupled
channel analysis of experimental data. The presence of an extremely broad J^pi
= 2^+ ``intruder'' resonance is confirmed, while a new 1^+ and very broad 4^+
resonance are discovered. A previously known 22 MeV 2^+ resonance is likely
resolved into two resonances. The experimental J^pi T = 3^(+)? resonance at 22
MeV is determined to be 3^-0, and the experimental 1^-? (at 19 MeV) and 4^-?
resonances to be isospin 0.Comment: 16 pages, LaTe
Does Positronium Form in the Universe ?
Positronium (the bound state of electron and positron) has been thought to be
formed after proton decay (yr) through collisional recombination and
then decays by pair annihilation, thereby changing the matter content of the
universe. We revisit the issue of the formation of positronium in the long-term
future of the universe in light of recent indication that the universe is
dominated by dark energy and dark matter. We find that if the equation of state
of dark energy is less than -1/3 (including the cosmological constant
), then the formation of positronium would not be possible, while it is
possible through bound-bound transitions for -1/3\siml w\siml-0.2, or through
collisional recombination for w\simg-0.2. The radiation from \epm pair
annihilation cannot dominate over \epm, while that from proton decay will
dominate over baryon and \epm for a while but not over dark matter.Comment: 13 pages, to appear in JCA
Exchange Bias Induced by the Fe3O4 Verwey transition
We present a study of the exchange bias in different configurations of V2O3
thin films with ferromagnetic layers. The exchange bias is accompanied by a
large vertical shift in the magnetization. These effects are only observed when
V2O3 is grown on top of Ni80Fe20 permalloy. The magnitude of the vertical shift
is as large as 60% of the total magnetization which has never been reported in
any system. X-Ray diffraction studies show that the growth conditions promote
the formation of a ferrimagnetic Fe3O4 interlayer. The change in the easy
magnetization axis of Fe3O4 across the Verwey transition at 120 K is correlated
with the appearance of exchange bias and vertical shift in magnetization. Both
phenomena disappear above 120 K, indicating for the first time a direct
relationship between the magnetic signature of the Verwey transition and
exchange bias.Comment: Accepted for publication Physical Review
Chaotic Scattering and Capture of Strings by Black Hole
We consider scattering and capture of circular cosmic strings by a
Schwarzschild black hole. Although being a priori a very simple axially
symmetric two-body problem, it shows all the features of chaotic scattering. In
particular, it contains a fractal set of unstable periodic solutions; a
so-called strange repellor. We study the different types of trajectories and
obtain the fractal dimension of the basin-boundary separating the space of
initial conditions according to the different asymptotic outcomes. We also
consider the fractal dimension as a function of energy, and discuss the
transition from order to chaos.Comment: RevTeX 3.1, 9 pages, 5 figure
Method and System for Diagnosis of \u3cem\u3eLawsonia Intracellularis\u3c/em\u3e
A method, system, and kit are provided for diagnosing L. intracellularis infection or exposure in a subject. The method includes purifying whole L. intracellularis from host cells and host debris produced in or on a suitable medium and adhering the purified whole L. intracellularis on a suitable material to form an antigen substrate for determining whether a subject produces L. intracellularis-specific antibodies against the antigen to thereby indicate L. intracellularis exposure or infection in the subject. The kit includes purified whole L. intracellularis produced from host cells and host debris adhered to a suitable material to form an antigen substrate adapted for screening serum from a subject. A method for diagnosing L. intracellularis exposure or infection in a subject includes acquiring a serum sample from a subject, introducing the serum sample to an antigen substrate followed by detecting a presence of L. intracellularis-specific antibodies in the serum
- …