Determining the distribution of values of stochastic impulses acting on a discrete system in relation to their intensity

In our previous works we introduced and applied a mathematical model that allowed us to calculate the approximate distribution of the values of stochastic impulses $η_{i}$ forcing vibrations of an oscillator with damping from the trajectory of its movement. The mathematical model describes correctly the functioning of a physical RLC system if the coefficient of damping is large and the intensity λ of impulses is small. It is so because the inflow of energy is small and behaviour of RLC is stable. In this paper we are going to present some experiments which characterize the behaviour of an oscillator RLC in relation to the intensity parameter λ, precisely to λ E(η). The parameter λ is a constant in the exponential distribution of random variables $τ_{i}$, where $τ_{i} = t_{i} - t_{i - 1}$, i = 1, 2, ... are intervals between successive impulses

Cooperative business models in steel enterprises in Poland

The paper presents the concept of cooperative business models in steel enterprises in Poland. The starting point is the presentation of the concept of business models, which is defined as a way of doing business based on cooperation between enterprises. This paper presents two collaborative business models, namely outsourcing and alliance networks, comparing the theoretical assumptions with the results of research carried out in steel enterprises in Poland

Determining the distribution of stochastic impulses acting on a high frequency system through an analysis of its vibrations

The motion of an oscillator with damping excited by impulses has the form $ξ_t = \frac{1}{\sqrt{a^2 - b^2}} \sum_{0 <t_i<t}η_i exp(-b(t-t_i)) sin(\sqrt{a^2 - b^2} (t - t_i))$, where $ξ_t$ is the deviation of the oscillator from its balanced position and $t_i$ is the time of action of an impulse of the value η_i. Under appropriate assumptions regarding random variables ${t_{i+1} - t_i}_{i=1}^\infty$ and ${η_i}_{i=1}^\infty ξ_{t}$ is a process which, in the limit as t tends to infinity, is stationary and ergodic. This fact allows us to derive a linear system of equations determining the approximate distribution of variables $η_{i}$ whenever the course of the oscillator is known in a sufficiently large interval of time. These equations will be verified in the experiment executed on an electric oscillator RLC of high frequency

Salmonella contamination of pig farm environment, Poland, 2014

Although pork is considered an important source of Salmonella infections, the introduction of control programs in pig farms are not obligatory in the EU. To resolve current epidemiological situation, monitoring of pig farms was introduced in Poland in 2014. The paper reports the first year outputs of the survey

Efficacy and Safety of Intravenous rtPA in Ischemic Strokes Due to Small-Vessel Occlusion: Systematic Review and Meta-Analysis

Intravenous recombinant tissue plasminogen activator (iv-rtPA) has been routinely used to treat ischemic stroke for 25 years, following large clinical trials. However, there are few prospective studies on the efficacy and safety of this therapy in strokes attributed to cerebral small vessel disease (SVD). We evaluated functional outcome (modified Rankin scale, mRS) and symptomatic intracerebral hemorrhage (sICH) using all available data on the effects of iv-rtPA in SVD-related ischemic stroke (defined either using neuroimaging, clinical features, or both). Using fixed-effect and random-effects models, we calculated the pooled effect estimates with regard to excellent and favorable outcomes (mRS=0-1 and 0-2 respectively, at 3 months), and the rate of sICH. Twenty-three studies fulfilled the eligibility criteria, 11 of which were comparative, and there were only 3 randomized clinical trials. In adjusted analyses, there was an increased odds of excellent outcome (adjusted OR=1.53, 95% CI: 1.29-1.82, I2: 0%) or favorable outcome (adjusted OR=1.68, 95% CI: 1.31-2.15,I2: 0%) in patients who received iv-rtPA compared with placebo. Across the six studies which reported it, the incidence of sICH was higher in the treatment group (M-H RR = 8.83, 95% CI: 2.76-28.27). The pooled rate of sICH in patients with SVD administered iv-rtPA was only 0.72% (95% CI: 0.12%-1.64%). We conclude that when ischemic stroke attributed to SVD is considered separately, available data on the effects of iv-rtPA therapy are insufficient for the highest level of recommendation, but it seems to be safe. Although further therapeutic trials in SVD-related ischemic stroke appear to be justified, our findings should not prevent its continued use for this group of patients in clinical practice

On Unbounded Composition Operators in L2L^2-Spaces

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied

The Extended Synthesis: Something Old, Something New

Abstract The eclipse of Darwinism began to end in the 1980s and hangs in the balance today. We need an Extended Synthesis, using “extension” metaphorically. We must extend back in time to recover important aspects of Darwinism that were set aside, and then lost during neo-Darwinism, then move forward beyond neo-Darwinism to encompass new data and concepts. The most comprehensive framework for the Extended Synthesis is the Major Transitions in Evolution. The Extended Synthesis rests comfortably within a philosophical perspective in which biology does not need to be connected with other areas of science in order to justify itself. I am attracted to an older concept in which biology needs a covering law to connect it with the rest of the natural sciences. Darwin implicated a “higher law,” but did not specify it. If we can elucidate that law, the Extended Synthesis will become the Unified Theory of Biology called for by Brooks and Wiley 25 years ago