345 research outputs found
Characterization of the DNA binding and structural properties of the BRCT region of human replication factor C p140 subunit
ProtChe
Modelling the response of phytoplankton in a shallow lake (Loch Leven, UK) to changes in lake retention time and water temperature.
The phytoplankton community of Loch Leven in 2005 was modelled and subjected to a combination of different flushing rates and water temperatures in order to assess the lake’s sensitivity to these two climatic drivers. Whilst the simulated annual mean total chlorophyll a proved relatively insensitive to these changes, at the species level marked changes were recorded. Some species responded positively to increased temperature (e.g. Aulacoseira), some negatively (e.g. Asterionella), whilst others were negatively affected by increased flow (e.g. Aphanocapsa) and others enhanced (e.g. Stephanodiscus). However, this relationship with flow was season dependent with, for example, a simulated increase in summer inflows actually benefiting some species through increased nutrient supply, whereas an equivalent increase in flow in wetter seasons would have negatively affected those species (i.e. through flushing loss). Overall, the simulations showed that the range of species types simulated in the community was sufficient for one species to always benefit from the changing niches created by the multiple climatic drivers applied in this study. The level of exploitation by such a species was only constrained by the nutrient carrying capacity of the system, which led to the overall dampened response in the total chlorophyll a measure, both at the annual and season scale. Thus, whilst overall biomass showed relatively little reaction to the two climatic drivers tested, the phytoplankton community composition responded markedly
Semi- and Non-relativistic Limit of the Dirac Dynamics with External Fields
We show how to approximate Dirac dynamics for electronic initial states by
semi- and non-relativistic dynamics. To leading order, these are generated by
the semi- and non-relativistic Pauli hamiltonian where the kinetic energy is
related to and , respectively. Higher-order
corrections can in principle be computed to any order in the small parameter
v/c which is the ratio of typical speeds to the speed of light. Our results
imply the dynamics for electronic and positronic states decouple to any order
in v/c << 1.
To decide whether to get semi- or non-relativistic effective dynamics, one
needs to choose a scaling for the kinetic momentum operator. Then the effective
dynamics are derived using space-adiabatic perturbation theory by Panati et. al
with the novel input of a magnetic pseudodifferential calculus adapted to
either the semi- or non-relativistic scaling.Comment: 42 page
Microcirculatory perfusion is preserved during off-pump but not on-pump cardiac surgery
OBJECTIVE: This study investigated the perioperative course of microcirculatory perfusion in off-pump compared with on-pump surgery. Additionally, the impact of changes in systemic hemodynamics, hematocrit, and body temperature was studied. DESIGN: Prospective, nonrandomized, observational study. SETTING: Tertiary university hospital. PARTICIPANTS: Patients undergoing coronary artery bypass grafting with (n = 13) or without (n = 13) use of cardiopulmonary bypass. INTERVENTIONS: Microcirculatory measurements were obtained at 5 time points ranging from induction of anesthesia to ICU admission. MEASUREMENTS AND MAIN RESULTS: Microcirculatory recordings were performed with sublingual sidestream dark field imaging. Despite a comparable reduction in intraoperative blood pressure between groups, the perfused vessel density decreased more than 20% after onset of extracorporeal circulation but remained stable in the off-pump group. The reduction in microvascular perfusion in the on-pump group was further paralleled by decreased hematocrit and temperature. Although postbypass hematocrit levels and body temperature were restored to similar levels as in the off-pump group, the median microvascular flow index remained reduced after bypass (2.4 [2.3-2.7]) compared with baseline (2.8 [2.7-2.9]; p = 0.021). CONCLUSIONS: Microcirculatory perfusion remained unaltered throughout off-pump surgery. In contrast, microvascular perfusion declined after initiation of cardiopulmonary bypass and did not recover in the early postoperative phase
Prospects for comparing European hospitals in terms of quality and safety
Purpose. Being able to compare hospitals in terms of quality and safety between countries is important for a number of
reasons. For example, the 2011 European Union directive on patients’ rights to cross-border health care places a requirement
on all member states to provide patients with comparable information on health-care quality, so that they can make an
informed choice. Here, we report on the feasibility of using common process and outcome indicators to compare hospitals
for quality and safety in five countries (England, Portugal, The Netherlands, Sweden and Norway).
Main Challenges Identified. The cross-country comparison identified the following seven challenges with respect to comparing
the quality of hospitals across Europe: different indicators are collected in each country; different definitions of the same
indicators are used; different mandatory versus voluntary data collection requirements are in place; different types of organizations
oversee data collection; different levels of aggregation of data exist (country, region and hospital); different levels of
public access to data exist; and finally, hospital accreditation and licensing systems differ in each country.
Conclusion. Our findings indicate that if patients and policymakers are to compare the quality and safety of hospitals across
Europe, then further work is urgently needed to agree the way forward. Until then, patients will not be able to make
informed choices about where they receive their health care in different countries, and some governments will remain in the
dark about the quality and safety of care available to their citizens as compared to that available in neighbouring countries
A Novel Combined Term Suggestion Service for Domain-Specific Digital Libraries
Interactive query expansion can assist users during their query formulation
process. We conducted a user study with over 4,000 unique visitors and four
different design approaches for a search term suggestion service. As a basis
for our evaluation we have implemented services which use three different
vocabularies: (1) user search terms, (2) terms from a terminology service and
(3) thesaurus terms. Additionally, we have created a new combined service which
utilizes thesaurus term and terms from a domain-specific search term
re-commender. Our results show that the thesaurus-based method clearly is used
more often compared to the other single-method implementations. We interpret
this as a strong indicator that term suggestion mechanisms should be
domain-specific to be close to the user terminology. Our novel combined
approach which interconnects a thesaurus service with additional statistical
relations out-performed all other implementations. All our observations show
that domain-specific vocabulary can support the user in finding alternative
concepts and formulating queries.Comment: To be published in Proceedings of Theories and Practice in Digital
Libraries (TPDL), 201
Moving towards adaptive search in digital libraries
Search applications have become very popular over the last two decades, one of the main drivers being the advent of the Web. Nevertheless, searching on the Web is very different to searching on smaller, often more structured collections such as digital libraries, local Web sites, and intranets. One way of helping the searcher locating the right information for a specific information need in such a collection is by providing well-structured domain knowledge to assist query modification and navigation. There are two main challenges which we will both address in this chapter: acquiring the domain knowledge and adapting it automatically to the specific interests of the user community. We will outline how in digital libraries a domain model can automatically be acquired using search engine query logs and how it can be continuously updated using methods resembling ant colony behaviour. © 2011 Springer-Verlag
Daily interruption of sedation in critically ill children: Study protocol for a randomized controlled trial
Background: In adult patients who are critically ill and mechanically ventilated, daily interruption of sedation (DSI) is an effective method of improving sedation management, resulting in a decrease of the duration of mechanical ventilation, the length of stay in the intensive care unit (ICU) and the length of stay in the hospital. It is a safe and effective approach and is common practice in adult ICUs. For critically ill children it is unknown if DSI is effective and feasible. The aim of this multicenter randomized controlled trial is to evaluate the safety and
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