The Northwest Passage is a sea route – or, to be exact, it is a collected name for four routes – that connect Europe and East Asia. Despite its considerable length (it spans circa 5780 kilometers) and notorious nautical difficulties it provides a decent alternative to the route through the Panama Canal due to being roughly 4000 kilometers shorter. In the present day the route is seasonal and is predominately operated by Canadian entities. Recently however it has seen in-creased interest due to climate change.

While Canada claims the waters of the Northwest Passage to be their internal waters, some experts say this claim, notwithstanding its historical grounds, may be deemed an abuse of sovereignty. Canada exercises creeping jurisdiction there, with Article 234 of the United Nations Convention on the Law of the Sea (UNCLOS 1982) as its sole justification. The United States, on the other hand, believes the Passage is in fact a strait connecting two areas of open sea and thus should remain part of international waters. On 11 January 1988 USA and Canada have signed an agreement on cooperation inthe Arctic.

The Author predicts the more disagreements over the Northwest Passage in the coming years as the core problem continues to be unresolved.

Organized security groups are operational on board some commercial vessels. These are professional units comprised of personnel whose only duties are to ensure that the overall physical safety of the vessel is maintained. Since maritime law does not take a position regarding such services, it can be concluded that the formation and maintenance of them is legal. Nevertheless, in order for potential actions taken by such groups to be acknowledged as legal, they must not exceed repelling direct attacks on the guarded vessel. It is not likely that attempts will be made in the nearest future to bring this issue under the detailed regulation of international law. The principles guiding the actions o f security groups are governed by the laws of the country of the ship’s flag. The role of the security officer has increased significantly within the hierarchy of the ship’s command. On the majority of large passenger vessels this is now a full-time position, and the person in charge of security is directly subordinate to the captain.

The objective of research concerned verifying the accuracy of the location and shape of selected lakes presented on topographical maps from various periods, drawn up on different scales. The area of research covered lakes situated in North- Western Poland on the Międzychód-Sieraków Lakeland . An analysis was performed of vector maps available in both analogue and digital format. The scales of these studies range from 1:50 000 to 1:10 000. The source materials were current for the years 1907 through 2013. The shape and location of lakes have been verified directly by means of field measurements performed using the GPS technology with an accuracy class of RTK. An analysis was performed of the location and shape of five lakes. The analysed water regions were vectorised, and their vector images were used to determine quantitative features: the area and length of the shoreline. Information concerning the analysed lakes obtained from the maps was verified on the basis of direct field measurements performed using a GPS RTK receiver. Use was made of georeferential corrections provided by the NAVGEO service or a virtual reference station generated by the ASG EUPOS system. A compilation of cartographic and field data formed the basis for a comparison of the actual area and the length of the shoreline of the studied lakes. Cartographic analyses made it possible to single out the most reliable cartographic sources, which could be used for the purposes of hydrographical analyses. The course of shorelines shows the attached map.

In the paper, an effective way to design asymmetrical optics for a uniform vertical surface illumination was presented. Assessment of the obtained distribution of luminance (illuminance) on the illuminated surface is done almost at the same time as designing the optical system elements. Advantage of the final application of the presented method in 3D will be independence from the implementation of time-consuming simulations in order to verify the already designed optics. Understanding the method and its application is simple and intuitive. Observing the luminance distribution, created on the illuminated surface almost at the same time as its design, allows to see the effect of adding the next elements of the optical system on this distribution.

The authors criticize the claims relating to the functioning of the National Committee on Ethical Review of Animal Research made in the paper „Five years of difficult experiences with the Act of the protection of animals used for scientific or educational purposes dated of January 15, 2015” published in „Nauka” (3/2020) relating to the functioning of the National Ethics Committee on Animal Experimentation. The comment proves many statements of that paper blatantly false given either statistical data or legal regulations. It includes the duties of the National Ethics Committee, right of non-governmental organizations to participate in administrative proceedings, conflict of interest, and the approach of the National Ethics Committee to appeals from the decisions made by local committees. The authors prove that the paper’s suggestions of the alleged misconduct by the National Ethics Committee on Animal Experimentation are ill-founded and result from the poorly understood legal situation as well as lack of reference to relevant empirical data.

The study is devoted to a parametric analysis of the stability and load carrying capacity of prismatic segment shells built of rectangular sections of cylindrical shells and subjected to compression. Segment shells (columns) with a constant crosssectional area (weight) have been analysed and all the results obtained have been compared with the results obtained for the cylindrical shell with a radius R and a thickness c; First, an influence of geometrical parameters of the cross-section of single-layer isotropic shells has been analysed and such profiles have been sought for which the load carrying capacity is significantly higher than in the case of the cylindrical shell. Then, for a selected shape of the shell (apart from higher load carrying capacity, this choice could be influenced by other factors such as, e.g. easiness of manufacturing), an effect of the arrangement and thickness of orthotropic layers of the shell (laminate) on the stability and load carrying capacity has been investigated. The analysis has shown that one can design a segment shell made of the same orthotropic material and characterised by higher resistance to buckling and load carrying capacity than a single-layer cylindrical orthotropic shell. The results are depicted in the form of plots.

The aim of the study was to assess the physiological stiffness of the normal canine jejunal mucosa based on shear wave elastography. The study was carried out on 60 dogs. In all the animals studied, the abdominal ultrasound was carried out using the SuperSonic Imagine Aixplorer system. The site of the jejunal elastography was determined using standard ultrasonography and all the measurements were carried out thrice. The stiffness of the area examined was determined during each measurement. Mean values were calculated based on the results obtained. The normal stiffness of the jejunal mucosa ranged from 1.305 kPa to 9.319 kPa (mean 5.31 ± 2.04 kPa). Based on our findings, we determined the range of normal values of the jejunal mucosal stiffness in healthy dogs. In addition, shear wave elastography was found to be safe and easy to perform. Moreover, it did not require anaesthesia or patient immobilisation for long periods.

The analysis of influence of mould withdrawal rate on the solidification process of CMSX-4 single crystal castings produced by Bridgman

method was presented in this paper. The predicted values of temperature gradient, solidification and cooling rate, were determined at the

longitudinal section of casting blade withdrawn at rate from 1 to 6mm/min using ProCAST software. It was found that the increase of

withdrawal rate of ceramic mould results in the decrease of temperature gradient and the growth of cooling rate, along blade height. Based

on results of solidification parameter G/R (temperature gradient/solidification rate), maximum withdrawal rate of ceramic mould

(3.5 mm/min), which ensures lower susceptibility to formation process of new grain defects in single crystal, was established. It was

proved that these defects can be formed in the bottom part of casting at withdrawal rate of 4 mm/min. The increase of withdrawal rate to 5

and 6 mm/min results in additional growth of susceptibility of defects formation along the whole height of airfoil.