50,118 research outputs found
Lost Lives: Miscarriages of Justice in Capital Cases
Gross discusses the incidence of erroneous convictions for capital murder, which are systematic consequences of the natuere of homicide prosection in general and capital prosecution in particular
Electromagnetic structure of the deuteron
Recent measurements of the deuteron electromagnetic structure functions A, B,
and extracted from high energy elastic scattering, and the cross
sections and asymmetries extracted from high energy photodisintegration
, are reviewed and compared to theory. The theoretical
calculations range from nonrelativistic and relativistic models using the
traditional meson and baryon degrees of freedom, to effective field theories,
to models based on the underlying quark and gluon degrees of freedom of QCD,
including nonperturbative quark cluster models and perturbative QCD. We review
what has been learned from these experiments, and discuss why elastic
scattering and photodisintegration seem to require very different theoretical
approaches, even though they are closely related experimentally.Comment: review paper; 93 pages, 35 figure
Image Processing Instrumentation for Giardia lamblia Detection
Currently, the identification and enumeration of Giardia Iamblia cysts are based upon microscopic methods requiring individuals proficient in this area. It is a tedious process which consumes time that could be constructively used elsewhere. This project attempts to alleviate that burden by employing a computer to automatically process Indirect Fluorescent Antibody (IFA) prepared slides using digital image processing techniques. A computer controlled frame grabber, in conjunction with a CCD TV camera mounted on the epi-fluorescence microscope phototube, captures the light intensities of the objects in view under the microscope objective. The captured image is stored as pixels, with each pixel having a numerical value that can be altered using linear contrast enhancement and bit-slicing to emphasize the cysts and eliminate the majority of unwanted objects from the image. The altered image is then analyzed by a vector trace routine for typical area and perimeters characteristic to Giardia lamblia cysts. Objects in the image matching these characteristics are most likely cysts and are added to a running tally of the number of cysts present on the slide
The stability of the spectator, Dirac, and Salpeter equations for mesons
Mesons are made of quark-antiquark pairs held together by the strong force.
The one channel spectator, Dirac, and Salpeter equations can each be used to
model this pairing. We look at cases where the relativistic kernel of these
equations corresponds to a time-like vector exchange, a scalar exchange, or a
linear combination of the two. Since the model used in this paper describes
mesons which cannot decay physically, the equations must describe stable
states. We find that this requirement is not always satisfied, and give a
complete discussion of the conditions under which the various equations give
unphysical, unstable solutions
Yesterday, today and tomorrow: A perspective of CFD at NASA's Ames Research Center
The opportunity to reflect on the computational fluid dynamics (CFD) progam at the NASA Ames Research Center (its beginning, its present state, and its direction for the future) is afforded. Essential elements of the research program during each period are reviewed, including people, facilities, and research problems. The burgeoning role that CFD is playing in the aerospace business is discussed, as is the necessity for validated CFD tools. The current aeronautical position of this country is assessed, as are revolutionary goals to help maintain its aeronautical supremacy in the world
The cadmium electrode: Review of the status of research
Investigations characterizing the negative cadmium electrode used in a nickel cadmium battery cell are summarized with citations to references where more detailed information is available. Emphasis is placed on data pertinent to aerospace applications. An evaluation of some of the published results of cadmium electrode research is included
Two-photon excitation of nitric oxide fluorescence as a temperature indicator in unsteady gas-dynamic processes
A laser induced fluorescence technique, suitable for measuring fluctuating temperatures in cold turbulent flows containing very low concentrations of nitric oxide is described. Temperatures below 300 K may be resolved with signal to noise ratios greater than 50 to 1 using high peak power, tunable dye lasers. The method relies on the two photon excitation of selected ro-vibronic transitions. The analysis includes the effects of fluorescence quenching and shows the technique to be effective at all densities below ambient. Signal to noise ratio estimates are based on a preliminary measurement of the two photon absorptivity for a selected rotational transition in the NO gamma (0,0) band
Break-up fragment topology in statistical multifragmentation models
Break-up fragmentation patterns together with kinetic and configurational
energy fluctuations are investigated in the framework of a microcanonical model
with fragment degrees of freedom over a broad excitation energy range. As far
as fragment partitioning is approximately preserved, energy fluctuations are
found to be rather insensitive to both the way in which the freeze-out volume
is constrained and the trajectory followed by the system in the excitation
energy - freeze-out volume space. Due to hard-core repulsion, the freeze-out
volume is found to be populated un-uniformly, its highly depleted core giving
the source a bubble-like structure. The most probable localization of the
largest fragments in the freeze-out volume may be inferred experimentally from
their kinematic properties, largely dictated by Coulomb repulsion
Lockdown: Dynamic Control-Flow Integrity
Applications written in low-level languages without type or memory safety are
especially prone to memory corruption. Attackers gain code execution
capabilities through such applications despite all currently deployed defenses
by exploiting memory corruption vulnerabilities. Control-Flow Integrity (CFI)
is a promising defense mechanism that restricts open control-flow transfers to
a static set of well-known locations. We present Lockdown, an approach to
dynamic CFI that protects legacy, binary-only executables and libraries.
Lockdown adaptively learns the control-flow graph of a running process using
information from a trusted dynamic loader. The sandbox component of Lockdown
restricts interactions between different shared objects to imported and
exported functions by enforcing fine-grained CFI checks. Our prototype
implementation shows that dynamic CFI results in low performance overhead.Comment: ETH Technical Repor
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