Analysis of Tourism Service Quality in Kołobrzeg Region by Means of Time Series Models

The undertaken study shows that methods that take into account time series can be successfully used in analysis of parameters of tourist comfort and in evaluation of hotel services.Przeprowadzone badania wskazują, że metody szeregów czasowych mogą być skutecznie zastosowane w badaniu wskaźników turystycznych i ocenie jakości usług hotelarskich

Tree-level contributions to B -> Xs gamma

Weak radiative decay B -> X_s gamma is known to be a loop-generated process. However, it does receive tree-level contributions from CKM-suppressed b -> u ubar s gamma transitions. In the present paper, we evaluate such contributions together with similar ones from the QCD penguin operators. For a low value of the photon energy cutoff E_0 ~ m_b/20 that has often been used in the literature, they can enhance the inclusive branching ratio by more than 10%. For E_0 = 1.6 GeV or higher, the effect does not exceed 0.4%, which is due to phase-space suppression. Our perturbative results contain collinear logarithms that depend on the light quark masses m_q (q=u,d,s). We have allowed m_b/m_q to vary from 10 to 50, which corresponds to values of m_q that are typical for the constituent quark masses. Such a rough method of estimation may be improved in the future with the help of fragmentation functions once the considered effects begin to matter in the overall error budget for BR(B -> X_s gamma).Comment: v3: Corrected factors of 2 in the subdominant T_3 contributions. Minor changes in the numerical results (Table II

Infectious Disease Monitoring of European Bison (<em>Bison bonasus</em>)

In 2019, the 90th anniversary of the restitution of European bison (wisent) will be celebrated. Therefore, the chapter discusses the past, present, and future health threats of the Bison bonasus species that was on the edge of world extinction at the beginning of the twentieth century and was restituted with great efforts from many researchers, breeders, forestry workers, and caretakers. Due to the dramatic genetic “bottleneck” that depleted the gene pool, increasing the inbred of today’s European bison, the breeding may face problems of decreased fertility, deficiency in growth, and increased susceptibility to diseases. While the increasing numbers of European bison may be enjoyed by breeders, the suitable habitat for the largest herbivore in Europe shrinks with increasing human population density, forestry, and agricultural activity. Additional threats include inappropriate management based on animal farming rather than sylvatic ecosystems, need for supplementary winter feeding, and establishment of breeding of related species such as American bison (Bison bison) in Europe. The control of European bison exposure to pathogens through passive and active surveillance is a key component of the species conservation. Hereby, the current knowledge on the epidemiology of the most significant infectious diseases in European bison is presented

Comparison of circular- and linear-stapled gastrojejunostomy in laparoscopic Roux-en-Y gastric bypass : a multicenter study

Introduction : Laparoscopic Roux-en-Y gastric bypass (LRYGB) is a common, well-established procedure, but no consensus regarding selection of the gastrojejunostomy (GJ) technique has been reached, and standardization of this precise technique is far from being achieved. Aim : To compare circular-stapled and linear-stapled GJ in LRYGB in terms of operative time and postoperative complications. Material and methods: This retrospective case-control study compared the perioperative and postoperative outcomes of LRYGB with a circular-stapled (LRYGB-CS) versus linear-stapled (LRYGB-LS) gastrojejunostomy. All patients, operated on in two academic referral care centers for bariatric surgery, were enrolled from April 2013 to June 2016. 457 patients were included (255 and 202 respectively in the LRYGB-CS and LRYGB-LS groups). After matching the groups for age, sex, body mass index, arterial hypertension, and presence of type 2 diabetes in a 1 : 1 ratio, 99 patients were enrolled in each. Results : The total operative time was longer in the LRYGB-LS group (140 vs. 85 min, p < 0.001). The postoperative hemorrhage and wound infection rates were lower in the LRYGB-LS group (2.1% vs. 10.3%, p = 0.021, and 1.0% vs. 9.3%, p = 0.011). The readmission rates were comparable (8.2% vs. 6.1%, p = 0.593). There was no significant difference in the incidence of gastrojejunostomy leakage, stricture, port-site hernia, or marginal ulcer. Conclusions : Both anastomosis types for LRYGB are safe and have low and comparable risks of postoperative complications. After LRYGB-CS, postoperative bleeding and wound infections are slightly more frequent; however, the operative time is shorter

Unbiased estimators for random design regression

In linear regression we wish to estimate the optimum linear least squares predictor for a distribution over d-dimensional input points and real-valued responses, based on a small sample. Under standard random design analysis, where the sample is drawn i.i.d. from the input distribution, the least squares solution for that sample can be viewed as the natural estimator of the optimum. Unfortunately, this estimator almost always incurs an undesirable bias coming from the randomness of the input points. In this paper we show that it is possible to draw a non-i.i.d. sample of input points such that, regardless of the response model, the least squares solution is an unbiased estimator of the optimum. Moreover, this sample can be produced efficiently by augmenting a previously drawn i.i.d. sample with an additional set of d points drawn jointly from the input distribution rescaled by the squared volume spanned by the points. Motivated by this, we develop a theoretical framework for studying volume-rescaled sampling, and in the process prove a number of new matrix expectation identities. We use them to show that for any input distribution and $\epsilon>0$ there is a random design consisting of $O(d\log d+ d/\epsilon)$ points from which an unbiased estimator can be constructed whose square loss over the entire distribution is with high probability bounded by $1+\epsilon$ times the loss of the optimum. We provide efficient algorithms for generating such unbiased estimators in a number of practical settings and support our claims experimentally