1,094 research outputs found
On the necessity of complexity
Wolfram's Principle of Computational Equivalence (PCE) implies that universal
complexity abounds in nature. This paper comprises three sections. In the first
section we consider the question why there are so many universal phenomena
around. So, in a sense, we week a driving force behind the PCE if any. We
postulate a principle GNS that we call the Generalized Natural Selection
Principle that together with the Church-Turing Thesis is seen to be equivalent
to a weak version of PCE. In the second section we ask the question why we do
not observe any phenomena that are complex but not-universal. We choose a
cognitive setting to embark on this question and make some analogies with
formal logic. In the third and final section we report on a case study where we
see rich structures arise everywhere.Comment: 17 pages, 3 figure
Tungsten Behavior at High Temperature and High Stress
Recently reported results on the tungsten lifetime/fatigue tests under conditions expected in the Neutrino Factory target have strengthened the case of solid target option for a Neutrino Factory. This paper gives description of the detailed measurements of the tungsten properties at high temperature and high stress. We have performed extensive set of measurements of the surface displacement and velocity of the tungsten wires that were stressed by passing a fast, high current pulse through a thin sample. Radial and longitudinal oscillations of the wire were measured by a Laser Doppler Vibrometer. The wire was operated at temperatures of 300-2500 K by adjusting the pulse repetition rate. In doing so we have tried to simulate the conditions (high stress and temperature) expected at the Neutrino Factory. Most important result of this study is an experimental confirmation that strength of tungsten remains high at high temperature and high stress. The experimental results have been found to agree very well with LS-DYNA modelling results
Effect of Late Season Supplementation on Performance of Yearling Steers Grazing Mixed Native Range or Cool Season, Russian Wildrye Pastures
Seventy-six yearling, black-baldy steers were utilized in a grazing experiment to study the effect of Level of Late summer, early fall protein supplement (1 versus 2 lb., 40% all natural) and type of f all pasture (mixed native range versus Russian wildrye) on average daily gain. Cattle were purchased i n May as part of a larger group and gained at the rate of 1.4 lb. per head daily prior to initiation of the study on September 1, 1987. Average daily gain was not affected by pasture type. Steers grazing native range and Russian wildrye gained .81 and .72 lb. per head daily, respectively, during September and October. Daily gain was significantly (P\u3c.05) greater for steers receiving 2 lb. of supplement than for steers receiving 1 lb. (1.01 vs .515 lb..per head daily, respectively). Providing 2 lb. of a 40% all natural protein supplement improved range utilization for growth
First African record of Leucocytozoon tawaki (Apicomplexa: Leucocytozoidae) from the Jackass Penguin Spheniscus demersus
The occurrence of Leucocytozoon tawaki is recorded from blood smears of the jackass penguin Spheniscus demersus taken along the South African coast. Illese records represent both the first African specimens of this parasite as well as the first records since its description from the Fiordland crested penguin Eudyptes pachyrhynchus in New Zealand in 1976
Babesia peircei sp. nov. from the jackass penguin
An avian piroplasm, Babesia peircei sp. nov. is described from the jackass penguin Spheniscus demersus. Morphological differences between Babesia peircei sp. nov. and the other valid Babesia spp. are discussed together with the possible vectors
Cosmic String Cusps with Small-Scale Structure: Their Forms and Gravitational Waveforms
We present a method for the introduction of small-scale structure into
strings constructed from products of rotation matrices. We use this method to
illustrate a range of possibilities for the shape of cusps that depends on the
properties of the small-scale structure. We further argue that the presence of
structure at cusps under most circumstances leads to the formation of loops at
the size of the smallest scales. On the other hand we show that the
gravitational waveform of a cusp remains generally unchanged; the primary
effect of small-scale structure is to smooth out the sharp waveform emitted in
the direction of cusp motion.Comment: RevTeX, 8 pages. Replaced with version accepted for publication by
PR
Weak force detection with superposed coherent states
We investigate the utility of non classical states of simple harmonic
oscillators, particularly a superposition of coherent states, for sensitive
force detection. We find that like squeezed states a superposition of coherent
states allows displacement measurements at the Heisenberg limit. Entangling
many superpositions of coherent states offers a significant advantage over a
single mode superposition states with the same mean photon number.Comment: 6 pages, no figures: New section added on entangled resources.
Changes to discussions and conclusio
Correlated Errors in Quantum Error Corrections
We show that errors are not generated correlatedly provided that quantum bits
do not directly interact with (or couple to) each other. Generally, this
no-qubits-interaction condition is assumed except for the case where two-qubit
gate operation is being performed. In particular, the no-qubits-interaction
condition is satisfied in the collective decoherence models. Thus, errors are
not correlated in the collective decoherence. Consequently, we can say that
current quantum error correcting codes which correct single-qubit-errors will
work in most cases including the collective decoherence.Comment: no correction, 3 pages, RevTe
Do actions occur inside the body?
The paper offers a critical examination of Jennifer Hornsby's view that actions are internal to the body. It focuses on three of Hornsby's central claims: (P) many actions are bodily movements (in a special sense of the word “movement”) (Q) all actions are tryings; and (R) all actions occur inside the body. It is argued, contra Hornsby, that we may accept (P) and (Q) without accepting also the implausible (R). Two arguments are first offered in favour of the thesis (Contrary-R): that no actions occur inside the body. Three of Hornsby's arguments in favour of R are then examined. It is argued that we need to make a distinction between the causes and the causings of bodily movements (in the ordinary sense of the word “movement”) and that actions ought to be identified with the latter rather than the former. This distinction is then used to show how Hornsby's arguments for (R) may be resisted
D-term inflation and neutrino mass
We study a -term inflation scenario in a model extended from the minimal
supersymmetric standard model (MSSM) by two additional abelian factor groups
focussing on its particle physics aspects. Condensates of the fields related to
the inflation can naturally give a possible solution to both the -problem
in the MSSM and the neutrino mass through their nonrenormalizable couplings to
the MSSM fields. Mixings between neutrinos and neutralinos are also induced by
some of these condensates. Small neutrino masses are generated by a weak scale
seesaw mechanism as a result of these mixings. Moreover, the decay of the
condensates may be able to cause the leptogenesis. Usually known discrepancy
between both values of a Fayet-Iliopoulos -term which are predicted by the
COBE normalization and also by an anomalous U(1) in the weakly-coupled
superstring might be reconciled.Comment: 21 pages, LaTeX, small modifications, one reference adde
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