597 research outputs found
Impact of implementing a fast-track protocol and standardized guideline for the management of pediatric appendicitis
Background: In 2017, a provincial guideline was created to fast track and standardize care for pediatric appendicitis in Alberta. We conducted a study to determine the impact of implementation of the guideline at our institution on length of stay (LOS), antibiotic stewardship efforts and costs. Methods: We performed a retrospective review of the charts of all patients younger than 18 years of age who underwent appendectomy at our institution in 2 periods: before guideline implementation (Dec. 1, 2016, to May 31, 2017) and after implementation (Dec. 1, 2017, to May 31, 2018). We compared LOS, duration of antibiotic therapy, 30-day postdischarge complication rates and variable cost between the 2 cohorts. Results: Of the 276 total appendectomy procedures performed, 185 were for simple appendicitis (81 before guideline implementation and 104 after implementation), and 91 were for complicated appendicitis (44 and 47, respectively). The median LOS was shorter in the postimplementation cohort for both simple and complicated appendicitis (15.5 h [interquartile range (IQR) 12-19 h] v. 17.0 h [IQR 13-22 h], p = 0.03; and 3.0 d [IQR 2-4 d] v. 3.0 d [IQR 3-5 d], p = 0.05, respectively). Patients with complicated appendicitis had fewer antibiotic days after guideline implementation; the difference was statistically significant for patients without diffuse peritoneal contamination or abscess formation (p = 0.02). There were no differences between the cohorts with respect to 30-day rates of complications, including emergency department visits, readmission and surgical site infections. After guideline implementation, the average variable cost per patient was reduced by 75 842 for our institution. Conclusion: The implementation of a provincial guideline aimed at standardizing care in pediatric appendicitis at our institution was associated with shortened LOS, improved antibiotic stewardship efforts and reduced cost of care. Other institutions may replicate our model of a standardized pathway in the management of pediatric appendicitis in an effort to improve the quality of patient care and reduce health care costs
Compressed Membership for NFA (DFA) with Compressed Labels is in NP (P)
In this paper, a compressed membership problem for finite automata, both
deterministic and non-deterministic, with compressed transition labels is
studied. The compression is represented by straight-line programs (SLPs), i.e.
context-free grammars generating exactly one string. A novel technique of
dealing with SLPs is introduced: the SLPs are recompressed, so that substrings
of the input text are encoded in SLPs labelling the transitions of the NFA
(DFA) in the same way, as in the SLP representing the input text. To this end,
the SLPs are locally decompressed and then recompressed in a uniform way.
Furthermore, such recompression induces only small changes in the automaton, in
particular, the size of the automaton remains polynomial.
Using this technique it is shown that the compressed membership for NFA with
compressed labels is in NP, thus confirming the conjecture of Plandowski and
Rytter and extending the partial result of Lohrey and Mathissen; as it is
already known, that this problem is NP-hard, we settle its exact computational
complexity. Moreover, the same technique applied to the compressed membership
for DFA with compressed labels yields that this problem is in P; for this
problem, only trivial upper-bound PSPACE was known
Functional characterization of a melon alcohol acyl-transferase gene family involved in the biosynthesis of ester volatiles. Identification of the crucial role of a threonine residue for enzyme activity
Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by
alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var.
cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging
from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4).
All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show
differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl
esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3
also accepts a wide range of substrates but with very strong preference for producing benzyl acetate.
Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl
acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is
related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating
268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished
activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase
during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in
antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene
(1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the
multiplicity of AAT genes accounts for the great diversity of esters formed in melon
Effect of the GaAsP shell on optical properties of self-catalyzed GaAs nanowires grown on silicon
We realize growth of self-catalyzed core-shell GaAs/GaAsP nanowires (NWs) on
Si substrates using molecular-beam epitaxy. Transmission electron microscopy
(TEM) of single GaAs/GaAsP NWs confirms their high crystal quality and shows
domination of the zinc-blende phase. This is further confirmed in optics of
single NWs, studied using cw and time-resolved photoluminescence (PL). A
detailed comparison with uncapped GaAs NWs emphasizes the effect of the GaAsP
capping in suppressing the non-radiative surface states: significant PL
enhancement in the core-shell structures exceeding 2000 times at 10K is
observed; in uncapped NWs PL is quenched at 60K whereas single core-shell
GaAs/GaAsP NWs exhibit bright emission even at room temperature. From analysis
of the PL temperature dependence in both types of NW we are able to determine
the main carrier escape mechanisms leading to the PL quench
Season of birth and Alzheimer's disease: a population-based study in Saguenay-Lac-St-Jean/Québec (IMAGE Project)
The birth distribution of 399 cases of Alzheimer's disease (AD) identified in the region of Saguenay-Lac-St-Jean (Québec) was compared with that of: (a) the population currently living in the area; and (b) the population born during the same period in the area. AD cases have been recruited since 1986 by the IMAGE Project. Cases and controls were grouped according to the month of birth and according to the day of birth using density estimation. Analyses showed a significant deficit of births in the month of May. We believe these preliminary results deserve further attention and we suggest two possible explanations that could lead to a deficit of AD births at specific periods during the year
Experimental measurement-device-independent quantum digital signatures
The development of quantum networks will be paramount towards practical and secure telecommunications. These networks will need to sign and distribute information between many parties with information-Theoretic security, requiring both quantum digital signatures (QDS) and quantum key distribution (QKD). Here, we introduce and experimentally realise a quantum network architecture, where the nodes are fully connected using a minimum amount of physical links. The central node of the network can act either as a totally untrusted relay, connecting the end users via the recently introduced measurement-device-independent (MDI)-QKD, or as a trusted recipient directly communicating with the end users via QKD. Using this network, we perform a proof-of-principle demonstration of QDS mediated by MDI-QKD. For that, we devised an efficient protocol to distil multiple signatures from the same block of data, thus reducing the statistical fluctuations in the sample and greatly enhancing the final QDS rate in the finite-size scenario
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