3,338 research outputs found
Logarithmic Corrections to Scaling in the --Model
We study the distribution of partition function zeroes for the --model in
two dimensions. In particular we find the scaling behaviour of the end of the
distribution of zeroes in the complex external magnetic field plane in the
thermodynamic limit (the Yang--Lee edge) and the form for the density of these
zeroes. Assuming that finite--size scaling holds, we show that there have to
exist logarithmic corrections to the leading scaling behaviour of thermodynamic
quantities in this model. These logarithmic corrections are also manifest in
the finite--size scaling formulae and we identify them numerically. The method
presented here can be used to check the compatibility of scaling behaviour of
odd and even thermodynamic functions in other models too.Comment: 3 pages, latex, 2 figure
Generalized retarded integral inequalities
We prove some new retarded integral inequalities. The results generalize
those in [J. Math. Anal. Appl. 301 (2005), no. 2, 265--275].Comment: Changes suggested by the referee don
Logarithmic Corrections to Scaling in the Two Dimensional --Model
By expressing thermodynamic functions in terms of the edge and density of
Lee--Yang zeroes, we relate the scaling behaviour of the specific heat to that
of the zero field magnetic susceptibility in the thermodynamic limit of the
--model in two dimensions. Assuming that finite--size scaling holds, we
show that the conventional Kosterlitz--Thouless scaling predictions for these
thermodynamic functions are not mutually compatable unless they are modified by
multiplicative logarithmic corrections. We identify these logarithmic
corrections analytically in the case of the specific heat and numerically in
the case of the susceptibility. The techniques presented here are general and
can be used to check the compatibility of scaling behaviour of odd and even
thermodynamic functions in other models too.Comment: 11 pages, latex, 4 figure
Relative Cost-effectiveness Of Using An Extensively Hydrolyzed Casein Formula In Managing Infants With Cow’s Milk Allergy In Brazil
To estimate the cost-effectiveness of three alternative dietetic strategies for cow’s milk allergy in Brazil: 1) using an extensively hydrolyzed casein formula (eHCF; Nutramigen) as a first-line formula, but switching to an amino acid formula (AAF) if infants remain symptomatic; 2) using an AAF as a first-line formula and then switching to an eHCF after 4 weeks once infants are symptom-free, but switching back to an AAF if infants become symptomatic; and 3) using an AAF as a first-line formula and keeping all infants on that formula. The analysis was conducted from the perspective of the Brazilian public health care system, Sistema Único de Saude. Methods: Decision modeling was used to estimate the probability of immunoglobulin E (IgE)-mediated and non-IgE-mediated allergic infants developing tolerance to cow’s milk by 12 months from starting a formula. The models also estimated the Sistema Único de Saude cost (at 2013/2014 prices) of managing infants over 12 months after starting a formula, as well as the relative cost-effectiveness of each of the dietetic strategies. Results: The probability of developing tolerance to cow’s milk by 12 months from starting a formula was higher among infants with either IgE-mediated or non-IgE-mediated allergy who were initially fed with an eHCF, compared with those who were initially fed with an AAF. The total health care cost of initially feeding an eHCF to cow’s milk allergic infants was less than that of initially feeding both IgE-mediated and non-IgE-mediated infants with an AAF. Conclusion: Within the study’s limitations, using an eHCF instead of an AAF for the first-line management of newly-diagnosed infants with cow’s milk allergy affords a cost-effective use of publicly funded resources, since it improves the outcome for less cost. © 2016 Guest et al.862963
Normal forms and linearization of resonant vector fields with multiple eigenvalues
We discuss the linearization and normal forms of resonant vector fields X(x) = Ax +a(x), where
A has one double or triple eigenvalue or a pair of double eigenvalues: we present a simple way
of identifying the resonant monomials that have to appear in its normal form, and also effective conditions on the nonlinearity a(x) for the resonant vector field to be linearizable.Fundação Calouste Gulbenkian (FCG)Fundação para a Ciência e a Tecnologia (FCT
Hadronic Charmed Meson Decays Involving Tensor Mesons
Charmed meson decays into a pseudoscalar meson P and a tensor meson T are
studied. The charm to tensor meson transition form factors are evaluated in the
Isgur-Scora-Grinstein-Wise (ISGW) quark model. It is shown that the
Cabibbo-allowed decay is dominated by the
W-annihilation contribution and has the largest branching ratio in
decays. We argue that the Cabibbo-suppressed mode
should be suppressed by one order of magnitude relative to . When the finite width effect of the tensor resonances is taken
into account, the decay rate of is generally enhanced by a factor of
. Except for , the predicted branching ratios
of decays are in general too small by one to two orders of magnitude
compared to experiment. However, it is very unlikely that the
transition form factors can be enhanced by a factor of within the
ISGW quark model to account for the discrepancy between theory and experiment.
As many of the current data are still preliminary and lack sufficient statistic
significance, more accurate measurements are needed to pin down the issue.Comment: 11 page
On the value of from the analysis of the SLAC/BCDMS deep inelastic scattering data
We performed NLO QCD analysis of the nonsinglet part of the combined
SLAC/BCDMS data on with the extraction of and high twist
contribution. It was shown that the value of obtained in the
analysis is sensitive to the statistical inference procedures dealing with
systematic errors on the data. The fit with the complete account of
point-to-point correlations of the data gave the value of
, to be compared with the previously
reported value of . This new value of
is compatible with the LEP measurements and the world average. The
high twist contribution being strongly anti-correlated with the value of
became lower than it was previously reported.Comment: 9 pages, LATEX, 2 figures (PS), report-no added, English improved,
misprints corrected, minor changes of the tex
Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study
Background
Single embryo transfer (SET) remains underutilized as a strategy to reduce multiple gestation risk in IVF, and its overall lower pregnancy rate underscores the need for improved techniques to select one embryo for fresh transfer. This study explored use of comprehensive chromosomal screening by array CGH (aCGH) to provide this advantage and improve pregnancy rate from SET.
Methods
First-time IVF patients with a good prognosis (age <35, no prior miscarriage) and normal karyotype seeking elective SET were prospectively randomized into two groups: In Group A, embryos were selected on the basis of morphology and comprehensive chromosomal screening via aCGH (from d5 trophectoderm biopsy) while Group B embryos were assessed by morphology only. All patients had a single fresh blastocyst transferred on d6. Laboratory parameters and clinical pregnancy rates were compared between the two groups.
Results
For patients in Group A (n=55), 425 blastocysts were biopsied and analyzed via aCGH (7.7 blastocysts/patient). Aneuploidy was detected in 191/425 (44.9%) of blastocysts in this group. For patients in Group B (n=48), 389 blastocysts were microscopically examined (8.1 blastocysts/patient). Clinical pregnancy rate was significantly higher in the morphology+aCGH group compared to the morphology-only group (70.9 and 45.8%, respectively; p=0.017); ongoing pregnancy rate for Groups A and B were 69.1 vs. 41.7%, respectively (p=0.009). There were no twin pregnancies.
Conclusion
Although aCGH followed by frozen embryo transfer has been used to screen at risk embryos (e.g., known parental chromosomal translocation or history of recurrent pregnancy loss), this is the first description of aCGH fully integrated with a clinical IVF program to select single blastocysts for fresh SET in good prognosis patients. The observed aneuploidy rate (44.9%) among biopsied blastocysts highlights the inherent imprecision of SET when conventional morphology is used alone. Embryos randomized to the aCGH group implanted with greater efficiency, resulted in clinical pregnancy more often, and yielded a lower miscarriage rate than those selected without aCGH. Additional studies are needed to verify our pilot data and confirm a role for on-site, rapid aCGH for IVF patients contemplating fresh SET
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