1,260 research outputs found
A posteriori agreement as a quality measure for readability prediction systems
All readability research is ultimately concerned with the research question whether it is possible for a prediction system to automatically determine the level of readability of an unseen text. A significant problem for such a system is that readability might depend in part on the reader. If different readers assess the readability of texts in fundamentally different ways, there is insufficient a priori agreement to justify the correctness of a readability prediction system based on the texts assessed by those readers. We built a data set of readability assessments by expert readers. We clustered the experts into groups with greater a priori agreement and then measured for each group whether classifiers trained only on data from this group exhibited a classification bias. As this was found to be the case, the classification mechanism cannot be unproblematically generalized to a different user group
Determination of nasal and oropharyngeal microbiomes in a multicenter population-based study – findings from Pretest 1 of the German National Cohort
We examined acceptability, preference and feasibility of collecting nasal and
oropharyngeal swabs, followed by microbiome analysis, in a population-based
study with 524 participants. Anterior nasal and oropharyngeal swabs were
collected by certified personnel. In addition, participants self-collected
nasal swabs at home four weeks later. Four swab types were compared regarding
(1) participants’ satisfaction and acceptance and (2) detection of microbial
community structures based on deep sequencing of the 16 S rRNA gene V1–V2
variable regions. All swabbing methods were highly accepted. Microbial
community structure analysis revealed 846 phylotypes, 46 of which were unique
to oropharynx and 164 unique to nares. The calcium alginate tipped swab was
found unsuitable for microbiome determinations. Among the remaining three swab
types, there were no differences in oropharyngeal microbiomes detected and
only marginal differences in nasal microbiomes. Microbial community structures
did not differ between staff-collected and self-collected nasal swabs. These
results suggest (1) that nasal and oropharyngeal swabbing are highly feasible
methods for human population-based studies that include the characterization
of microbial community structures in these important ecological niches, and
(2) that self-collection of nasal swabs at home can be used to reduce cost and
resources needed, particularly when serial measurements are to be taken
Orbital-order melting in rare-earth manganites: the role of super-exchange
We study the mechanism of orbital-order melting observed at temperature T_OO
in the series of rare-earth manganites. We find that many-body super-exchange
yields a transition-temperature T_KK that decreases with decreasing rare-earth
radius, and increases with pressure, opposite to the experimental T_OO. We show
that the tetragonal crystal-field splitting reduces T_KK further increasing the
discrepancies with experiments. This proves that super-exchange effects,
although very efficient, in the light of the experimentally observed trends,
play a minor role for the melting of orbital ordering in rare-earth manganites.Comment: 4 pages, 5 figure
Stochastic games on a product state space
We examine so-called product-games with an aperiodic transition structure, with respect to the average reward, for which we present an approach based on communicating states. For the general n-player case, we establish the existence of 0-equilibria. In addition, for the special case of two-player zero-sum games of this type, we show that both players have stationary 0-optimal strategies
The Nebraska Mathematics Readiness Project: Year 1 Evaluation Report
The Nebraska Math Readiness Project (NMRP) is a targeted curriculum designed for seniors who have plans of attending college, yet lack the foundational math skills needed for college-level courses. They are given a fourth-year mathematics class to help them improve their mathematical skills and prepare for required college math courses. The project is a collaboration between community colleges across the state and high schools within the Nebraska school districts
Nonadiabatic Dynamics of Ultracold Fermions in Optical Superlattices
We study the time-dependent dynamical properties of two-component ultracold
fermions in a one-dimensional optical superlattice by applying the adaptive
time-dependent density matrix renormalization group to a repulsive Hubbard
model with an alternating superlattice potential. We clarify how the time
evolution of local quantities occurs when the superlattice potential is
suddenly changed to a normal one. For a Mott-type insulating state at quarter
filling, the time evolution exhibits a profile similar to that expected for
bosonic atoms, where correlation effects are less important. On the other hand,
for a band-type insulating state at half filling, the strong repulsive
interaction induces an unusual pairing of fermions, resulting in some striking
properties in time evolution, such as a paired fermion co-tunneling process and
the suppression of local spin moments. We further address the effect of a
confining potential, which causes spatial confinement of the paired fermions.Comment: 4 pages, 5 figure
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