3,738 research outputs found
Mini-charged tau neutrinos?
Theoretically, the electric charge of the tau neutrino may be non-zero. The
experimental bound on the electric charge of the tau neutrino is many orders of
magnitude weaker than that for any other known neutrino. If the tau neutrino
does have a small electric charge, and its mass is greater than 1 MeV, then it
can annihilate sufficiently in the early Universe by electromagnetic
interactions to avoid conflict with the standard cosmology model. A novel
feature of this scenario is that there can be effectively less than three
neutrino species present during nucleosynthesis.Comment: 8 pages in LaTeX, 1 uuencoded figure file appended, PURD-TH-93-1
Unbroken versus broken mirror world: a tale of two vacua
If the Lagrangian of nature respects parity invariance then there are two
distinct possibilities: either parity is unbroken by the vacuum or it is
spontaneously broken. We examine the two simplest phenomenologically consistent
gauge models which have unbroken and spontaneously broken parity symmetries,
respectively. These two models have a Lagrangian of the same form, but a
different parameter range is chosen in the Higgs potential. They both predict
the existence of dark matter and can explain the MACHO events. However, the
models predict quite different neutrino physics. Although both have light
mirror (effectively sterile) neutrinos, the ordinary-mirror neutrino mixing
angles are unobservably tiny in the broken parity case. The minimal broken
parity model therefore cannot simultaneously explain the solar, atmospheric and
LSND data. By contrast, the unbroken parity version can explain all of the
neutrino anomalies. Furthermore, we argue that the unbroken case provides the
most natural explanation of the neutrino physics anomalies (irrespective of
whether evidence from the LSND experiment is included) because of its
characteristic maximal mixing prediction.Comment: About 15 pages, Late
Danalog: Digital Music Synthesizer
The Danalog is a 25 key portable digital music synthesizer that uses multiple synthesis methods and effects to generate sounds. Sound varieties included three synthesis methods including FM, subtractive, and sample-based, with up to eight adjustable parameters, at least four effects, including reverb, chorus, and flange, with five adjustable parameters, and at least two note polyphony, and a five band equalizer. The user would be able to adjust these effects using digital encoders and potentiometers and view the settings on two LCD screens.
The finals project was unable to meet the original design requirements. The FM synthesis method was primarily working in the end product. The synthesizer was built to produce two note polyphony. The LCD screens displayed the information about the synthesis method as the user plays
Intracellular Measurements of the Electrical Properties of Walled Cells
The electrical properties of plant (and other walled) cells have a tremendous impact on the transport of ions into or out of the cell. Ion transport is necessary for plant growth and survival. Thus, the electrical properties of the plant cell are crucial to the survival and growth of the plant. The most direct way to measure the electrical properties of the cell is intracellular impalement with a microelectrode. A range of techniques, their execution, and potential pitfalls are described in this chapter. Special attention is paid to dual impalement techniques to measure current–voltage relations of the cell
Consistent discretizations: the Gowdy spacetimes
We apply the consistent discretization scheme to general relativity
particularized to the Gowdy space-times. This is the first time the framework
has been applied in detail in a non-linear generally-covariant gravitational
situation with local degrees of freedom. We show that the scheme can be
correctly used to numerically evolve the space-times. We show that the
resulting numerical schemes are convergent and preserve approximately the
constraints as expected.Comment: 10 pages, 8 figure
Few-Shot Bayesian Imitation Learning with Logical Program Policies
Humans can learn many novel tasks from a very small number (1--5) of
demonstrations, in stark contrast to the data requirements of nearly tabula
rasa deep learning methods. We propose an expressive class of policies, a
strong but general prior, and a learning algorithm that, together, can learn
interesting policies from very few examples. We represent policies as logical
combinations of programs drawn from a domain-specific language (DSL), define a
prior over policies with a probabilistic grammar, and derive an approximate
Bayesian inference algorithm to learn policies from demonstrations. In
experiments, we study five strategy games played on a 2D grid with one shared
DSL. After a few demonstrations of each game, the inferred policies generalize
to new game instances that differ substantially from the demonstrations. Our
policy learning is 20--1,000x more data efficient than convolutional and fully
convolutional policy learning and many orders of magnitude more computationally
efficient than vanilla program induction. We argue that the proposed method is
an apt choice for tasks that have scarce training data and feature significant,
structured variation between task instances.Comment: AAAI 202
Out of Place, Out of Mind: Schema-Driven False Memory Effects for Object-Location Bindings
Events consist of diverse elements, each processed in specialized neocortical networks, with temporal lobe memory systems binding these elements to form coherent event memories. We provide a novel theoretical analysis of an unexplored consequence of the independence of memory systems for elements and their bindings, 1 that raises the paradoxical prediction that schema-driven false memories can act solely on the binding of event elements despite the superior retrieval of individual elements. This is because if 2, or more, schema-relevant elements are bound together in unexpected conjunctions, the unexpected conjunction will increase attention during encoding to both the elements and their bindings, but only the bindings will receive competition with evoked schema-expected bindings. We test our model by examining memory for object-location bindings in recognition (Study 1) and recall (Studies 2 and 3) tasks. After studying schema-relevant objects in unexpected locations (e.g., pan on a stool in a kitchen scene), participants who then viewed these objects in expected locations (e.g., pan on stove) at test were more likely to falsely remember this object-location pairing as correct, compared with participants that viewed a different unexpected object-location pairing (e.g., pan on floor). In recall, participants were more likely to correctly remember individual schema-relevant objects originally viewed in unexpected, as opposed to expected locations, but were then more likely to misplace these items in the original room scene to expected places, relative to control schema-irrelevant objects. Our theoretical analysis and novel paradigm provide a tool for investigating memory distortions acting on binding processes
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