9,567 research outputs found
City-wide Analysis of Electronic Health Records Reveals Gender and Age Biases in the Administration of Known Drug-Drug Interactions
The occurrence of drug-drug-interactions (DDI) from multiple drug
dispensations is a serious problem, both for individuals and health-care
systems, since patients with complications due to DDI are likely to reenter the
system at a costlier level. We present a large-scale longitudinal study (18
months) of the DDI phenomenon at the primary- and secondary-care level using
electronic health records (EHR) from the city of Blumenau in Southern Brazil
(pop. ). We found that 181 distinct drug pairs known to
interact were dispensed concomitantly to 12\% of the patients in the city's
public health-care system. Further, 4\% of the patients were dispensed drug
pairs that are likely to result in major adverse drug reactions (ADR)---with
costs estimated to be much larger than previously reported in smaller studies.
The large-scale analysis reveals that women have a 60\% increased risk of DDI
as compared to men; the increase becomes 90\% when considering only DDI known
to lead to major ADR. Furthermore, DDI risk increases substantially with age;
patients aged 70-79 years have a 34\% risk of DDI when they are dispensed two
or more drugs concomitantly. Interestingly, a statistical null model
demonstrates that age- and female-specific risks from increased polypharmacy
fail by far to explain the observed DDI risks in those populations, suggesting
unknown social or biological causes. We also provide a network visualization of
drugs and demographic factors that characterize the DDI phenomenon and
demonstrate that accurate DDI prediction can be included in healthcare and
public-health management, to reduce DDI-related ADR and costs
Enhancement of the critical temperature in iron-pnictide superconductors by finite size effects
Recent experiments have shown that, in agreement with previous theoretical
predictions, superconductivity in metallic nanostructures can be enhanced with
respect to the bulk limit. Motivated by these results we study finite size
effects (FSE) in an iron-pnictide superconductor. For realistic values of the
bulk critical temperature Tc ~ 20-50K, we find that, in the nanoscale region L
~ 10 nm, Tc(L) has a complicated oscillating pattern as a function of the
system size L. A substantial enhancement of Tc with respect to the bulk limit
is observed for different boundary conditions, geometries and two microscopic
models of superconductivity. Thermal fluctuations, which break long range
order, are still small in this region. Finally we show that the differential
conductance, an experimental observable, is also very sensitive to FSE.Comment: 4 pages, 3 figure
Recent advances and open challenges in percolation
Percolation is the paradigm for random connectivity and has been one of the
most applied statistical models. With simple geometrical rules a transition is
obtained which is related to magnetic models. This transition is, in all
dimensions, one of the most robust continuous transitions known. We present a
very brief overview of more than 60 years of work in this area and discuss
several open questions for a variety of models, including classical, explosive,
invasion, bootstrap, and correlated percolation
A matter of time: Implicit acquisition of recursive sequence structures
A dominant hypothesis in empirical research on the evolution of language is the following: the fundamental difference between animal and human communication systems is captured by the distinction between regular and more complex non-regular grammars. Studies reporting successful artificial grammar learning of nested recursive structures and imaging studies of the same have methodological shortcomings since they typically allow explicit problem solving strategies and this has been shown to account for the learning effect in subsequent behavioral studies. The present study overcomes these shortcomings by using subtle violations of agreement structure in a preference classification task. In contrast to the studies conducted so far, we use an implicit learning paradigm, allowing the time needed for both abstraction processes and consolidation to take place. Our results demonstrate robust implicit learning of recursively embedded structures (context-free grammar) and recursive structures with cross-dependencies (context-sensitive grammar) in an artificial grammar learning task spanning 9 days. Keywords: Implicit artificial grammar learning; centre embedded; cross-dependency; implicit learning; context-sensitive grammar; context-free grammar; regular grammar; non-regular gramma
Critical Cooperation Range to Improve Spatial Network Robustness
A robust worldwide air-transportation network (WAN) is one that minimizes the
number of stranded passengers under a sequence of airport closures. Building on
top of this realistic example, here we address how spatial network robustness
can profit from cooperation between local actors. We swap a series of links
within a certain distance, a cooperation range, while following typical
constraints of spatially embedded networks. We find that the network robustness
is only improved above a critical cooperation range. Such improvement can be
described in the framework of a continuum transition, where the critical
exponents depend on the spatial correlation of connected nodes. For the WAN we
show that, except for Australia, all continental networks fall into the same
universality class. Practical implications of this result are also discussed
Theory of Andreev reflection in a two-orbital model of iron-pnictide superconductors
A recently developed theory for the problem of Andreev reflection between a
normal metal (N) and a multiband superconductor (MBS) assumes that the incident
wave from the normal metal is coherently transmitted through several bands
inside the superconductor. Such splitting of the probability amplitude into
several channels is the analogue of a quantum waveguide. Thus, the appropriate
matching conditions for the wave function at the N/MBS interface are derived
from an extension of quantum waveguide theory. Interference effects between the
transmitted waves inside the superconductor manifest themselves in the
conductance. We provide results for a FeAs superconductor, in the framework of
a recently proposed effective two-band model and two recently proposed gap
symmetries: in the sign-reversed s-wave () scenario
resonant transmission through surface Andreev bound states (ABS) at nonzero
energy is found as well as destructive interference effects that produce zeros
in the conductance; in the extended s-wave ()
scenario no ABS at finite energy are found.Comment: 4 pages, 5 figure
Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures
Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizuremouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.Foundation for Science and Technology (FCT, Portugal); COMPETE; FEDER [PTDC/SAU-NEU/102612/2008, PTDC/NEU-OSD/0473/2012, PEst-C/SAU/LA0001/2013-2014, PEst-OE/EQB/LA0023/2013-2014]; FCT, Portugal [SFRH/BPD/78901/2011, SFRH/BD/77903/2011
Lateral resistance of log timber walls subjected to horizontal loads
The present works intends to represent a further step in the knowledge of timber log-houses through an
experimental approach, from which only few information is available. The main part of the experimental work is based
on in-plane static tests conducted on timber log walls with distinct transversal stiffness, two vertical compression levels
and two values of slenderness. Monotonic and cyclic tests were performed according to EN 12512:2001. The formers
were performed to define the elastic slip values and assessment of the failure mechanisms while the lasts allowed
evaluating impairment of strength, to measure the ductility and to quantify the energy dissipation. In a first step
research, an extensive characterization of the timber logs was made. The connection between the first timber log and the
basement was also evaluated.(undefined
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