198 research outputs found
An improvement of the Berry--Esseen inequality with applications to Poisson and mixed Poisson random sums
By a modification of the method that was applied in (Korolev and Shevtsova,
2009), here the inequalities
and
are proved for the
uniform distance between the standard normal distribution
function and the distribution function of the normalized sum of an
arbitrary number of independent identically distributed random
variables with zero mean, unit variance and finite third absolute moment
. The first of these inequalities sharpens the best known version of
the classical Berry--Esseen inequality since
by virtue of
the condition , and 0.4785 is the best known upper estimate of the
absolute constant in the classical Berry--Esseen inequality. The second
inequality is applied to lowering the upper estimate of the absolute constant
in the analog of the Berry--Esseen inequality for Poisson random sums to 0.3051
which is strictly less than the least possible value of the absolute constant
in the classical Berry--Esseen inequality. As a corollary, the estimates of the
rate of convergence in limit theorems for compound mixed Poisson distributions
are refined.Comment: 33 page
Gaussian Bounds for Noise Correlation of Functions
In this paper we derive tight bounds on the expected value of products of
{\em low influence} functions defined on correlated probability spaces. The
proofs are based on extending Fourier theory to an arbitrary number of
correlated probability spaces, on a generalization of an invariance principle
recently obtained with O'Donnell and Oleszkiewicz for multilinear polynomials
with low influences and bounded degree and on properties of multi-dimensional
Gaussian distributions. The results derived here have a number of applications
to the theory of social choice in economics, to hardness of approximation in
computer science and to additive combinatorics problems.Comment: Typos and references correcte
Building a network of ADPKD reference centres across Europe: the EuroCYST initiative
BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic inherited kidney disease, affecting an estimated 600 000 individuals in Europe. The disease is characterized by age-dependent development of a multiple cysts in the kidneys, ultimately leading to end-stage renal failure and the need of renal replacement therapy in the majority of patients, typically by the fifth or sixth decade of life. The variable disease course, even within the same family, remains largely unexplained. Similarly, assessing disease severity and prognosis in an individual with ADPKD remains difficult. Epidemiological studies are limited due to the fragmentation of ADPKD research in Europe. METHODS: The EuroCYST initiative aims: (i) to harmonize and develop common standards for ADPKD research by starting a collaborative effort to build a network of ADPKD reference centres across Europe and (ii) to establish a multicentric observational cohort of ADPKD patients. This cohort will be used to study factors influencing the rate of disease progression, disease modifiers, disease stage-specific morbidity and mortality, health economic issues and to identify predictive disease progression markers. Overall, 1100 patients will be enrolled in 14 study sites across Europe. Patients will be prospectively followed for at least 3 years. Eligible patients will not have participated in a pharmaceutical clinical trial 1 year before enrollment, have clinically proven ADPKD, an estimated glomerular filtration rate (eGFR) of 30 mL/min/1.73 m(2) and above, and be able to provide written informed consent. The baseline visit will include a physical examination and collection of blood, urine and DNA for biomarker and genetic studies. In addition, all participants will be asked to complete questionnaires detailing self-reported health status, quality of life, socioeconomic status, health-care use and reproductive planning. All subjects will undergo annual follow-up. A magnetic resonance imaging (MRI) scan will be carried out at baseline, and patients are encouraged to undergo a second MRI at 3-year follow-up for qualitative and quantitative kidney and liver assessments. CONCLUSIONS: The ADPKD reference centre network across Europe and the observational cohort study will enable European ADPKD researchers to gain insights into the natural history, heterogeneity and associated complications of the disease as well as how it affects the lives of patients across Europ
The EULAR Study Group for Registers and Observational Drug Studies: comparability of the patient case mix in the European biologic disease modifying anti-rheumatic drug registers
Objective. Under the auspices of the European League Against Rheumatism (EULAR), a study group of investigators representing European biologic DMARD (bDMARD) registers was convened. The purpose of this initial assessment was to collect and compare a cross section of patient characteristics and collate information on the availability of potential confounders within these registers. Methods. Baseline characteristics of patients starting their first bDMARD in an arbitrary year (2008) for the treatment of RA, including demographic and disease characteristics, bDMARD drug details and co-morbidities, were collected and compared across 14 European bDMARD registers. Results. A total of 5320 patients were included. Half the registers had restricted recruitment to certain bDMARDs during the study year. All registers's collected data on age, gender, disease duration, seropositivity for IgM-RF and 28-joint DAS (DAS28). The mean DAS28 ranged from 4.2 to 6.6 and the mean HAQ from 0.8 to 1.9. Current smoking ranged from 9% to 34%. Nine registers reported co-morbidities with varying prevalence. Conclusion. In addition to demonstrating European-wide collaboration across rheumatology bDMARD registers, this assessment identified differences in prescribing patterns, recruitment strategies and data items collected. These differences need to be considered when applying strategies for combined analysis. The lack of a common data model across Europe calls for further work to harmonize data collection across register
MICROBIOLOGICAL DETERMINATION OF LACTIC ACID BACTERIA FROM FERMENTED DAIRY PRODUCTS IN DIFFERENT STORAGE TIMES
Lactic acid bacteria evolution (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) from two Romanian fermented dairy products (yoghurt and sana) was followed in tree stages of storage during shelf-life: in first day of storage after processing; in the middle of storage period and in the last day of storage period.
An important decrease of lactic acid bacteria was observed to storage during shelf-life. This indicates a low stability of starter culture, viable germs being inhibited by other micro-organisms development (first Enterobacteriaceae then yeast and molds)
THE ANALYSIS OF PHYSICAL – CHEMICAL PARAMETERS OF MILK DURING HARD AND SEMI-HARD PASTE CHEESE PROCESSING
The aim of the present paper is the study of some physical-chemical parameters’ variation at the milk processing for obtaining cheese. For these investigations, it had been started from milk-raw material and finally it was analyzed some parameters (water content, fat, salt) for two cheese assortments obtained from analyzed milk:
- ?vai?er, cheese with hard paste and long period of maturation;
- Tilsit, cheese with semi-hard paste.
The physical-chemical exam betray a good quality of milk-raw material. As regarding the variation of the fat content reported to dried substance during maturation, it was found out low values after three months of maturation for all analyzed cases. During maturation the water content is decrease. Making a comparison between maturated cheese and fresh cheese, as regards salt content it is found out an increase for all samples. During maturation it is found out a decrease of protein content through it’s proteolitic degradation, resulting more simple compounds
RESEARCHES CONCERNING MICROBIOLOGICAL EVOLUTION OF LACTIC ACID BACTERIA TO YOGHURT STORAGE DURING SHELF-LIFE
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