303 research outputs found
Minimax optimization of a unimodal function by variable block derivative search with time delay
AbstractA minimax search plan is developed for locating the maximum of a unimodal function with a sequence of blocks of simultaneous evaluations of the derivative of the function. The search strategy permits any number of blocks and any number of experiments in each block. Further, any time delay is permissible where the time delay is the number of blocks placed after the m-th block but before the results of the m-th block become known. The proposed variable block search plan is optimal in the sense that for a required final interval of uncertainty, known to contain the point where the function attains its maximum, and for any given value for time delay and the number of experiments in each block, it has the largest possible initial interval. A method of optimizing the number of experiments per block is given. An extension to non-linear programming algorithms is given
Identifying crop variants with high resistant starch content to maintain healthy glucose homeostasis
Identifying dietary tools that prevent disordered insulin secretion from pancreatic β‐cells is an attractive strategy to combat the increasing prevalence of type 2 diabetes. Dietary resistant starch has been linked to improvements in the function of β‐cells, possibly via increased colonic fermentation and production of short‐chain fatty acids (SCFAs). Increasing the resistant starch content of commonly consumed foods could therefore maintain glucose homeostasis at the population level. As part of Biotechnology and Biological Sciences Research Council (BBSRC) Diet and Health Research Industry Club (DRINC) initiative, variants of Pisum sativum L. (pea) are being investigated to identify the features of pea starch that make it resistant to digestion and available for colonic fermentation and SCFA production. Parallel in vitro and in vivo studies are being conducted using both whole pea seeds and pea flour to facilitate a better understanding of how cells in the pea cotyledons are affected by processing and, in turn, how this influences starch digestibility. Trials in human volunteers are being used to monitor a full spectrum of short‐ and long‐term physiological responses relevant to pancreatic β‐cell function and glucose homeostasis. This project is providing new insights into variants of crops that are associated with the specific types of resistant starch that provide the best protection against defects in insulin secretion and function
Surgical outcomes of laparoscopic and open resection of benign liver tumours in the Netherlands: a nationwide analysis
Background: Data on surgical outcomes of laparoscopic liver resection (LLR) versus open liver resection (OLR) of benign liver tumour (BLT) are scarce. This study aimed to provide a nationwide overview of postoperative outcomes after LLR and OLR of BLT. Methods: This was a nationwide retrospective study including all patients who underwent liver resection for hepatocellular adenoma, haemangioma and focal nodular hyperplasia in the Netherlands from 2014 to 2019. Propensity score matching (PSM) was applied to compare 30-day overall and major morbidity and 30-day mortality after OLR and LLR. Results: In total, 415 patients underwent BLT resection of whom 230 (55.4%) underwent LLR. PSM for OLR and LLR resulted in 250 matched patients. Median (IQR) length of stay was shorter after LLR than OLR (4 versus 6 days, 5.0-8.0, p < 0.001). Postoperative 30-day overall morbidity was lower after LLR than OLR (12.0% vs. 22.4%, p = 0.043). LLR was associated with reduced 30-day overall morbidity in multivariable analysis (aOR:0.46, CI:0.22-0.95, p = 0.043). Both 30-day major morbidity and 30-day mortality were not different. Conclusions: LLR for BLT is associated with shorter hospital stay and reduced overall morbidity and is preferred if technically feasible.Transplant surger
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
Measurement of charm production at central rapidity in proton-proton collisions at TeV
The -differential production cross sections of the prompt (B
feed-down subtracted) charmed mesons D, D, and D in the rapidity
range , and for transverse momentum GeV/, were
measured in proton-proton collisions at TeV with the ALICE
detector at the Large Hadron Collider. The analysis exploited the hadronic
decays DK, DK, DD, and their charge conjugates, and was performed on a
nb event sample collected in 2011 with a
minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space
the -differential production cross sections at TeV
and our previous measurements at TeV. The results were compared
to existing measurements and to perturbative-QCD calculations. The fraction of
cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/307
Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at = 2.76 TeV
The yield of charged particles associated with high- trigger
particles ( GeV/) is measured with the ALICE detector in
Pb-Pb collisions at = 2.76 TeV relative to proton-proton
collisions at the same energy. The conditional per-trigger yields are extracted
from the narrow jet-like correlation peaks in azimuthal di-hadron correlations.
In the 5% most central collisions, we observe that the yield of associated
charged particles with transverse momenta GeV/ on the
away-side drops to about 60% of that observed in pp collisions, while on the
near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/350
A re-examination of the life and work of A.F.G. Kerr and of his colleagues and friends
Arthur Francis George Kerr’s life is reviewed and related to a previously published account. Kerr’s collecting activity
is analysed using an expanded version of the Thai Biogeography Group’s database of collections. 8,666 of the total 48,970 collections
are Kerr’s and 3,178 are those of his colleagues and friends. Therefore, the total number of collections made by Kerr and his
acquaintances is likely to be larger and more diverse than previously believed. Mapping of these data using GIS show that Kerr’s
collecting activities focussed on particular regions of Thailand at particular times. Also large areas of the country remained unexplored
by Kerr and his acquaintances: a pattern that, to some extent, persists to this day. The large, but dispersed, archive of Kerr’s
photographs, maps, living collections and correspondence indicate that he was a skilled photographer (taking at least 3,000 images),
cartographer (producing many hand-drawn maps) and exceptionally acute, accurate and detailed observer (filling numerous notebooks
and leaving other records). It is clear that digitising these collections to form an on-line dedicated website is highly desirable
to further progress on the flora of Thailand and surrounding countries and would form an unique record of the social history of early
20thC Thailand
Implementation and outcome of robotic liver surgery in the Netherlands: a nationwide analysis
Objective:To determine the nationwide implementation and surgical outcome of minor and major robotic liver surgery (RLS) and assess the first phase of implementation of RLS during the learning curve. Background:RLS may be a valuable alternative to laparoscopic liver surgery. Nationwide population-based studies with data on implementation and outcome of RLS are lacking. Methods:Multicenter retrospective cohort study including consecutive patients who underwent RLS for all indications in 9 Dutch centers (August 2014-March 2021). Data on all liver resections were obtained from the mandatory nationwide Dutch Hepato Biliary Audit (DHBA) including data from all 27 centers for liver surgery in the Netherlands. Outcomes were stratified for minor, technically major, and anatomically major RLS. Learning curve effect was assessed using cumulative sum analysis for blood loss. Results:Of 9437 liver resections, 400 were RLS (4.2%) procedures including 207 minor (52.2%), 141 technically major (35.3%), and 52 anatomically major (13%). The nationwide use of RLS increased from 0.2% in 2014 to 11.9% in 2020. The proportion of RLS among all minimally invasive liver resections increased from 2% to 28%. Median blood loss was 150 mL (interquartile range 50-350 mL] and the conversion rate 6.3% (n=25). The rate of Clavien-Dindo grade >= III complications was 7.0% (n=27), median length of hospital stay 4 days (interquartile range 2-5) and 30-day/in-hospital mortality 0.8% (n=3). The R0 resection rate was 83.2% (n=263). Cumulative sum analysis for blood loss found a learning curve of at least 33 major RLS procedures. Conclusions:The nationwide use of RLS in the Netherlands has increased rapidly with currently one-tenth of all liver resections and one-fourth of all minimally invasive liver resections being performed robotically. Although surgical outcomes of RLS in selected patient seem favorable, future prospective studies should determine its added value.Surgical oncolog
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