17,636 research outputs found
The Discovery of Neutrino Masses
The recent observation of neutrino oscillations with atmospheric and solar
neutrinos, implying that neutrinos are not massless, is a discovery of
paramount importance for particle physics and particle astrophysics. This
invited lecture discusses - hopefully in a way understandable also for the
non-expert - the physics background and the results mainly from the two most
relevant experiments, Super-Kamiokande and SNO. It also addresses the
implications for possible neutrino mass spectra. We restrict the discussion to
three neutrino flavours (nu_e, nu_mu, nu_tau), not mentioning a possible
sterile neutrino.Comment: Contribution to CF 200
Distinguishing Hidden Markov Chains
Hidden Markov Chains (HMCs) are commonly used mathematical models of
probabilistic systems. They are employed in various fields such as speech
recognition, signal processing, and biological sequence analysis. We consider
the problem of distinguishing two given HMCs based on an observation sequence
that one of the HMCs generates. More precisely, given two HMCs and an
observation sequence, a distinguishing algorithm is expected to identify the
HMC that generates the observation sequence. Two HMCs are called
distinguishable if for every there is a distinguishing
algorithm whose error probability is less than . We show that one
can decide in polynomial time whether two HMCs are distinguishable. Further, we
present and analyze two distinguishing algorithms for distinguishable HMCs. The
first algorithm makes a decision after processing a fixed number of
observations, and it exhibits two-sided error. The second algorithm processes
an unbounded number of observations, but the algorithm has only one-sided
error. The error probability, for both algorithms, decays exponentially with
the number of processed observations. We also provide an algorithm for
distinguishing multiple HMCs. Finally, we discuss an application in stochastic
runtime verification.Comment: This is the full version of a LICS'16 pape
A SYSTEM-WIDE APPROACH FOR ANALYZING THE EFFECT OF EXCHANGE RATES ON FRESH APPLE IMPORT DEMAND
This study examines the impact of changes in exchange rate and import market composition on fresh apple import demand using source differentiated import demand functions. We modify the standard Rotterdam model to incorporate exchange rate effects by revisiting Barten's fundamental matrix equation of consumer demand theory and viewing exchange rate as a "sticky" preference variable. The results show that the preference variable had a significant impact on UK but not on Malaysian and Saudi Arabian import demands.International Relations/Trade,
Diffusion-Induced Oscillations of Extended Defects
From a simple model for the driven motion of a planar interface under the
influence of a diffusion field we derive a damped nonlinear oscillator equation
for the interface position. Inside an unstable regime, where the damping term
is negative, we find limit-cycle solutions, describing an oscillatory
propagation of the interface. In case of a growing solidification front this
offers a transparent scenario for the formation of solute bands in binary
alloys, and, taking into account the Mullins-Sekerka instability, of banded
structures
A Collection Divided: an Analysis of Accession 16082, the Ohio Hopewell Site Collection at the Milwaukee Public Museum
This thesis investigates and documents sixty-one Ohio Hopewellian objects that form a collection currently housed at the Milwaukee Public Museum (MPM). The objects were excavated from the Hopewell site of Ross County, Ohio which lends its name to a renowned and geographically expansive archaeological cultural horizon. The meaning and interpretation of these MPM objects, and the site itself have evolved over time through decisions made by Native peoples, archaeologists, and museum curators. The MPM’s collection can be used as a conduit enabling discussion of the evolution of interpretations for the entire Hopewell site and the extraordinary number of artifacts which have been removed from it. Further, this collection is a mechanism for understanding decisions and practices in the nineteenth and twentieth century fields of archaeology and museology.
To fill displays at the Chicago World’s Colombian Exposition of 1893, Warren K. Moorehead excavated mounds at the Hopewell Mound Group in Ohio from 1891 to 1892. Thousands of objects removed from the site were transported to Chicago, later becoming one of the founding collections for the Field Museum (FM). Objects from the Hopewell site were used as a representative specimen type collection for identification of other Hopewellian sites throughout the Eastern Woodlands of the United States. On April 6th, 1945, the Milwaukee Public Museum received 61 objects from the Hopewell site in an exchange with the FM.
This thesis contains two components: a review of decisions made by varying constituents which affected and currently affect the objects and a descriptive analysis of the Hopewell collection at the MPM. First, the review focuses on the transition of these Hopewellian objects’ meaning over time though the decisions of Native peoples, archaeologists, and museum professionals. This begins with a history of the Hopewell site and archaeological practices associated with the site. Next, an object biography is presented, following the MPM Hopewell site collection artifacts journey from southern Ohio to Milwaukee, Wisconsin. The final portion of the review discusses the transition of Hopewellian objects’ interpretation over time in museums and National Parks. The second component of this thesis, includes examination and photography of the physical objects, assessment of provenience information, and a comparison to the larger Hopewell collection at the FM.
The goals of this thesis are to gather information and associate a largely unresearched collection at the MPM to an important archaeological site, connect to an expansive archaeological cultural horizon, and explore the related professional practices of the previous era. Data collected for this thesis will be provided to the MPM and submitted to the FM for potential incorporation into their “Ohio Hopewell” digital project. By including this information in the digital project, this small collection at the Milwaukee Public Museum will be linked to other Hopewellian objects now spread throughout the world, and as a result, will be more accessible for future research
Correlation between electric-field-induced phase transition and piezoelectricity in lead zirconate titanate films
We observed that electric field induces phase transition from tetragonal to
rhombohedral in polycrystalline morphotropic lead zirconate titanate (PZT)
films, as reported in 2011 for bulk PZT. Moreover, we evidenced that this
field-induced phase transition is strongly correlated with PZT film
piezoelectric properties, that is to say the larger the phase transition, the
larger the longitudinal piezoelectric coefficient d 33,eff . Although d 33,eff
is already comprised between as 150 to 170 pm/V, our observation suggests that
one could obtain larger d 33,eff values, namely 250 pm/V, by optimizing the
field-induced phase transition thanks to composition fine tuning
Growth and structural changes of viviparous mangrove propagules: the effect of environment on dispersal and establishment
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