1,422 research outputs found
Weight gain and dietary intake during pregnancy in industrialized countries - a systematic review of observational studies
Background: Gestational weight gain (GWG) above the recently recommended ranges is likely to be related to adverse pregnancy outcomes and therefore a challenge in industrialized countries. Aims: We conducted a systematic review on observational studies in order to gain more evidence on whether diets with lower caloric/protein content or other diets might be associated with lower GWG. Methods: We searched in MEDLINE and EMBASE for observational studies written in English or German reporting associations between diet and GWG in singleton pregnancies of healthy women in industrialized countries. Results: We identified 12 studies which met the inclusion criteria. Five studies suggested significant positive associations between energy intake and GWG, whereas three found no significant association. Further significant positive associations of GWG were reported with respect to protein intake, animal lipids, energy density and a number of different food servings per day, whereas intake of carbohydrates and vegetarian diet were associated with less GWG. Conclusions: We suggest that GWG might be reduced by lower energy intake in pregnancy
Prospect relativity: how choice options influence decision under risk.
In many theories of decision under risk (e.g., expected utility theory, rank-dependent utility theory, and prospect theory), the utility of a prospect is independent of other options in the choice set. The experiments presented here show a large effect of the available options, suggesting instead that prospects are valued relative to one another. The judged certainty equivalent for a prospect is strongly influenced by the options available. Similarly, the selection of a preferred prospect is strongly influenced by the prospects available. Alternative theories of decision under risk (e.g., the stochastic difference model, multialternative decision field theory, and range frequency theory), where prospects are valued relative to one another, can provide an account of these context effects
Structure calculation, refinement and validation using CcpNmr Analysis
CcpNmr Analysis provides a streamlined pipeline for both NMR chemical shift assignment and structure determination of biological macromolecules. In addition, it encompasses tools to analyse the many additional experiments that make NMR such a pivotal technique for research into complex biological questions. This report describes how CcpNmr Analysis can seamlessly link together all of the tasks in the NMR structure-determination process. It details each of the stages from generating NMR restraints [distance, dihedral,hydrogen bonds and residual dipolar couplings (RDCs)],exporting these to and subsequently re-importing them from structure-calculation software (such as the programs CYANA or ARIA) and analysing and validating the results obtained from the structure calculation to, ultimately, the streamlined deposition of the completed assignments and the refined ensemble of structures into the PDBe repository. Until recently, such solution-structure determination by NMR has been quite a laborious task, requiring multiple stages and programs. However, with the new enhancements to CcpNmr Analysis described here, this process is now much more intuitive and efficient and less error-prone
In Vitro Studies of Cells Grown on the Superconductor PrOxFeAs
The recent discovery of arsenic-based high temperature superconductors has
reignited interest in the study of superconductor : biological interfaces.
However, the new superconductor materials involve the chemistry of arsenic,
their toxicity remain unclear [ Nature, 2008, 452(24):922]. In this study the
possible adverse effects of this new family of superconductors on cells have
been examined. Cell culture studies in conjunction with microscopy and
viability assays were employed to examine the influence of arsenic-based
superconductor PrOxFeAs (x=0.75) material in vitro. Imaging data revealed that
cells were well adhered and spread on the surface of the superconductor.
Furthermore, cytotoxicity studies showed that cells were unaffected during the
time-course of the experiments, providing support for the biocompatibility
aspects of PrOxFeAs-based superconductor material.Comment: Are the FeAs based superconductors toxic
The importance of interocean exchange south of Africa in a numerical model
A fine resolution numerical model of the Southern Ocean (the Fine Resolution Antarctic Model (FRAM)) has been used to investigate the way in which heat is supplied to the South Atlantic. The heat budget in the model is compared with other estimates and is found to be broadly realistic. The temperature structure in the Atlantic, and therefore the meridional heat transport, depend heavily on the input of heat from the Indian Ocean via the Agulhas Retroflection region. FRAM is compared with three models which do not exhibit a significant input of heat from the Indian Ocean. These models also have a lower equatorward heat transport in the South Atlantic. Horizontal resolution affects the amount of Agulhas transfer with coarser resolution leading to lower heat transport in the Atlantic, a result which has implications for ocean models used in climate simulations
Rich Counter-Examples for Temporal-Epistemic Logic Model Checking
Model checking verifies that a model of a system satisfies a given property,
and otherwise produces a counter-example explaining the violation. The verified
properties are formally expressed in temporal logics. Some temporal logics,
such as CTL, are branching: they allow to express facts about the whole
computation tree of the model, rather than on each single linear computation.
This branching aspect is even more critical when dealing with multi-modal
logics, i.e. logics expressing facts about systems with several transition
relations. A prominent example is CTLK, a logic that reasons about temporal and
epistemic properties of multi-agent systems. In general, model checkers produce
linear counter-examples for failed properties, composed of a single computation
path of the model. But some branching properties are only poorly and partially
explained by a linear counter-example.
This paper proposes richer counter-example structures called tree-like
annotated counter-examples (TLACEs), for properties in Action-Restricted CTL
(ARCTL), an extension of CTL quantifying paths restricted in terms of actions
labeling transitions of the model. These counter-examples have a branching
structure that supports more complete description of property violations.
Elements of these counter-examples are annotated with parts of the property to
give a better understanding of their structure. Visualization and browsing of
these richer counter-examples become a critical issue, as the number of
branches and states can grow exponentially for deeply-nested properties.
This paper formally defines the structure of TLACEs, characterizes adequate
counter-examples w.r.t. models and failed properties, and gives a generation
algorithm for ARCTL properties. It also illustrates the approach with examples
in CTLK, using a reduction of CTLK to ARCTL. The proposed approach has been
implemented, first by extending the NuSMV model checker to generate and export
branching counter-examples, secondly by providing an interactive graphical
interface to visualize and browse them.Comment: In Proceedings IWIGP 2012, arXiv:1202.422
Human intestinal tissue tropism of intimin epsilon O103 Escherichia coli
Human intestinal in vitro organ culture was used to assess the tissue tropism of human isolates of Escherichia coli O103:H2 and O103:H- that express intimin F. Both strains showed tropism for follicle associated epithelium and limited adhesion to other regions of the small and large intestine. This is similar to the tissue tropism shown by intimin gamma enterohaemorrhagic (EHEC) O157:H7, but distinct from that of intimin a enteropathogenic (EPEC) O127:H6. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserve
Can we avoid high coupling?
It is considered good software design practice to organize source code into modules and to favour within-module connections (cohesion) over between-module connections (coupling), leading to the oft-repeated maxim "low coupling/high cohesion". Prior research into network theory and its application to software systems has found evidence that many important properties in real software systems exhibit approximately scale-free structure, including coupling; researchers have claimed that such scale-free structures are ubiquitous. This implies that high coupling must be unavoidable, statistically speaking, apparently contradicting standard ideas about software structure. We present a model that leads to the simple predictions that approximately scale-free structures ought to arise both for between-module connectivity and overall connectivity, and not as the result of poor design or optimization shortcuts. These predictions are borne out by our large-scale empirical study. Hence we conclude that high coupling is not avoidable--and that this is in fact quite reasonable
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