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Many constructions built by ancient civilization hold many mysteries and attract the attention of historians, archaeologists and tourists from all over the world. The most famous and enigmatical among them is the Great (Khufu's-Cheops') Pyramid on the Giza plateau in Egypt. The assignment, construction methods and especially the inside structure of the Pyramid have been the cause of heated debate among historians and researchers since ancient times. Unfortunately, not only researchers are interested in ancient structures and excavation sites of archaeological values, but also robbers and illegal seekers of archaeological values. This led to the partial destruction of the Pyramid by the order of the Arab caliph Al-Ma'mun in the 9th century AD. From the middle of the last century, the point of view has prevailed that only non-destructive testing methods are acceptable when examining ancient structures. In the 1960s, a technology was proposed for transilluminating the pyramids of Giza by muons, which are generated by cosmic rays in the Earth's atmosphere. This method gave promising results. Other means were also proposed, which include radar, as well as gravitational and vibration technologies. However, despite numerous attempts to use them, no significant success or discovery has been achieved. A discussion of these methods, their applications and partial successes is the subject of this article. [ABSTRACT FROM AUTHOR]

The study, preservation and restoration of the cultural heritage objects of mankind are not only of great cultural importance but also have a significant economic component because cultural values of past centuries attract tourists from all over the world. The use of modern technical and scientific achievements in the field of non-destructive testing makes it possible to obtain new knowledge about cultural objects regarding their origin and dating, as well as to contribute to their better restoration and preservation. An important component of their use is additional opportunities to identify high quality fakes of original cultural objects that have historical significance. The capabilities of various non-destructive testing (NDT) methods used to examine cultural objects are characterized by their penetration depth, resolution, and sensitivity to material properties. Thus, in many cases, it is necessary to perform multi-sensor non-destructive testing and creating large data sets that require an efficient evaluation. This article considers an example of using microwave (MW) holographic sensors for the examining of an old Orthodox Russian Icon dated of the late 19th century. The paper describes the technology of microwave holography, which has recently been applied to the examination of art works. Unlike the well-studied X-ray method, MW holography makes it possible to examine objects with one-sided access. Its other advantages are the relative cheapness of the equipment and the safety of use due to the low level of radiation. The article describes a MW holograms reconstruction algorithm, as well as a method for improving the quality of obtained MW images. The data collected at MW research of the Icon are compared with the results of X-ray examination and confirmed by subsequent opening and visual examination performed by professional restorers. [ABSTRACT FROM AUTHOR]

The stock‐specific distribution of maturing salmon in the North Pacific has been a persistent information gap that has prevented us from determining the ocean conditions experienced by individual stocks. This continues to impede understanding of the role of ocean conditions in stock‐specific population dynamics. We assessed scale archives for 17 sockeye salmon (Oncorhynchus nerka) stocks covering the entire North Pacific, from the Columbia River (Washington State and British Columbia) to Kamchatka Peninsula (Russia), to infer salmon locations during their last growing season before returning to their spawning grounds. The approach used, first pioneered in salmon stocks in the Atlantic, relies on the relationship between temporal changes in δ13C in salmon scales and sea surface temperature to estimate salmon distribution based on correlation strength. An advantage of this approach is that it does not require fish sampling at sea, but relies on existing fishery agency collections of salmon scales. Significant correlations were found for 7 of the stocks allowing us to propose plausible feeding grounds. Complementary information from δ15N, historical tagging studies, and connectivity analysis were used to further refine distribution estimates. This study is a first step toward estimating stock‐specific distributions of salmon in the North Pacific and provides a basis for the application of the approach to other salmon scale archives. This information has the potential to improve our ability to relate stock dynamics to ocean conditions, ultimately enabling improved stock management. For example, our estimated distributions of Bristol Bay and NE Pacific stocks demonstrated that they occupy different areas with a number of the former being distributed in the high productivity shelf waters of the Aleutian Islands and Bering Sea. This may explain why these stocks seem to have responded differently to changes in ocean conditions, and the long‐term trend of increased productivity of Bristol Bay sockeye. [ABSTRACT FROM AUTHOR]

Pink salmon, the most abundant Pacific salmon, have an obligate 2-year life cycle that leads to reproductively isolated even- and odd-year lineages. Using new and existing data, we examined the genetic structure of both lineages across their distributional range by genotyping 16 681 single-nucleotide polymorphisms for 383 individuals originating from seven pairs of even- and odd-year populations. Distinct differences in standing pools of genetic variation were identified between the lineages; we observed higher levels of heterozygosity, allelic richness, and significantly more private alleles in the odd-year lineage. However, the patterns of population structure were concordant between lineages: the Asian and northern Alaska populations displayed little differentiation but differed significantly from populations in southcentral Alaska and the Pacific Northwest. Our population structure results, in the context of known paleoecological information, suggest that both lineages occupied a northern Beringial refugium as well as a Cascadian refugium in North America during the Last Glacial Maximum. These results highlight the influence of historical patterns of habitat availability on contemporary population structure and support the hypothesis of a pre-glacial origin of the lineages. [ABSTRACT FROM AUTHOR]

We genotyped Chinook salmon ( Oncorhynchus tshawytscha) from the Bering Sea and North Pacific Ocean for 43 single-nucleotide polymorphisms (SNPs) to investigate seasonal distribution and migration patterns. We analyzed 3563 immature fish from 22 spatiotemporal strata; composition analyses were performed using genotype data from spawning stocks spanning the species range. Substantial variation in stock composition existed among spatial and seasonal strata. We inferred patterns of seasonal migration based upon these data along with data from previous tag, scale, and parasite studies. We found that stocks from western Alaska and Yukon River overwinter on the Alaska continental shelf then travel to the middle and western Bering Sea during spring-fall. Stocks from California to Southeast Alaska were distributed in Gulf of Alaska year-round, with a substantial portion of this group migrating northward to the eastern Bering Sea during spring-fall. Proportions of Russian stocks increase when moving east to west in both the Bering Sea and North Pacific Ocean. These data can be used to better understand the impacts of fisheries and climate change on this valuable resource. [ABSTRACT FROM AUTHOR]