High Degree Of Preservation Research Articles

Structural analysis of fossilized tree trunks from the Miocene Mydlovary Formation of the South Bohemian Basin (Czech Republic)

Tree trunks were found in situ in Miocene strata of the Mydlovary Formation of the South Bohemian Basin. Our study presents microscopic and chemical tissue analyses of these tree trunks. The trees were fossilized and flattened. However, they are well preserved, which made the analyses feasible. Good preservation of the tissues is indicated by the high Tissue Preservation Index, the high content of cellulose, and the slightly gelified state of the wood. The Gelification Index indicated that there was only limited alteration during diagenesis. Huminite macerals prevailed over liptinite and inertinite macerals, and two varieties of ulminite and textinite were distinguished, differing in colour reflection, light fluorescence, and reflectance values. The biomarker composition in the extracts of the fossil wood obtained by gas chromatography-mass spectrometry, included terpenoid signatures, supporting a relationship to the Family Cupressaceae s.s.. Gradual burial of the trees is indicated by the fact that they lay crosswise on top of each other. The character of the sedimentary environment and the physiological differences of the trees could explain the deformation and the high degree of preservation.

Metric evaluation of permanent canines for sexual estimation in the Collection “Prof. Dr. Romulo Lambre”, Buenos Aires, Argentina

IntroductionSex estimation is a fundamental aspect of forensic work as a mandatory step for the identification of human remains of unknown origin. The methodological analysis of the dentition as a sexual estimator is important due to its high degree of preservation. Considering the need for specific information regarding the potential of dentition for sex estimation in forensic cases from Argentina, the aim of this study is to evaluate the proposal previously developed by Luna (2019) in a local sample of human skeletal remains. Materials and methodsA sample of 152 permanent canines belonging to 98 individuals of both sexes was selected. The individuals belong to the Prof. Dr. Rómulo Lambre osteological collection (La Plata, Argentina). Luna's proposal (2019) was applied to estimate sex from canine crown and neck metrics, which considers direct measurements and different types of discriminant functions and logistic regressions. ResultsOnly the cervical mesiodistal diameter showed acceptable results (>75%) for sex estimation. Moreover, discriminant function 1 showed a posteriori probabilities of correct classifications greater than 0.75 and logistic regressions 1 and 3 offered acceptable overall results. ConclusionsThis proposal based on the metric recording of permanent canines constitutes an adequate methodological alternative in situations in which the diagnostic bone elements of sex are deteriorated or absent.

Evaluación métrica de caninos permanentes para la estimación sexual en la Colección “Prof. Dr. Rómulo Lambre”, Buenos Aires, Argentina

IntroductionSex estimation is a fundamental aspect of forensic work as a mandatory step for the identification of human remains of unknown origin. The methodological analysis of the dentition as a sexual estimator is important due to its high degree of preservation. Considering the need for specific information regarding the potential of dentition for sex estimation in forensic cases from Argentina, the aim of this study is to evaluate the proposal previously developed by Luna (2019) in a local sample of human skeletal remains. Materials and methodsA sample of 152 permanent canines belonging to 98 individuals of both sexes was selected- The individuals belong to the Prof. Dr. Rómulo Lambre osteological collection (La Plata, Argentina). Luna's proposal (2019) was applied to estimate sex from canine crown and neck metrics, which considers direct measurements and different types of discriminant functions and logistic regressions. ResultsOnly the cervical mesiodistal diameter showed acceptable results (>75%) for sex estimation. Moreover, discriminant function 1 showed a posteriori probabilities of correct classifications greater than 0.75 and logistic regressions 1 and 3 offered acceptable overall results. ConclusionsThis proposal based on the metric recording of permanent canines constitutes an adequate methodological alternative in situations in which the diagnostic bone elements of sex are deteriorated or absent.

Socioemotional wealth in volatile, uncertain, complex, and ambiguous contexts: The case of family firms in Latin America and the Caribbean

The paradoxical nature of Latin America and the Caribbean (LAC) provides unique opportunities to advance management theory. Focusing on a dominant theoretical framework, Socioemotional Wealth (SEW), we argue that contextual features of LAC, namely the concept of extended family and the volatile, uncertain, complex, and ambiguous (VUCA) environment, make family businesses “SEW intensive” (i.e., high degree of preservation and enhancement of various aspects of SEW) and “SEW sensitive” (i.e., high degree of firm responsiveness to external factors that are SEW-relevant). In turn, these SEW features influence decision making and approaches to dealing with performance hazards and venturing risks. While we use LAC as a specific context, our theorizing and 12 propositions are also relevant to guide future research on other regions of the world, such as parts of Africa, Asia, and the Middle East, where the concept of extended family is widespread and a VUCA environment is also predominant. Overall, we use the characteristics of the LAC context to challenge existing assumptions, advance theory, and guide future empirical research on family businesses.

Ekonometrijski modeli u vrednovanju prirodnih atraktivnosti za razvoj turizma na Goliji

Economic development in many countries depends on numerous sectors, and among them, the tourism sector stands out the most. In addition to attractive tourist destinations, tourist movements are directed towards unused, attractive areas with a high degree of preservation. The evaluation of such areas is of great importance for the planning of tourism development. Econometric models are used in their study. One of such areas in Serbia is the Natural Good - "Golija" Nature Park, "Golija-Studenica" Biosphere Reserve. The subject of the research paper is the assessment of the natural attractiveness of Golija using econometric models. The aim of the paper is to identify and evaluate resources relevant to the development of tourism in the Golija area. Within the methodological apparatus, a model based on numerical and statistical analysis, cartographic, analysis, synthesis, descriptive method was used as a general scientific method.

Biotopic diversity and ecomorphic analysis of the Gryshkiv lis tract (Poltava)

The study of ecosystem and biotope biodiversity of park ecosystems allows to identify the most valuable plant objects in their composition, to assess the degree of stability of existing groups and to identify current threats of anthropogenic impact on them. Gryshkiv Lis tract (Poltava, Kyiv region) is one of the centers of natural phytodiversity conservation and is an array of deciduous forests with an area of ​​about 50 hectares, located adjacent to residential areas of the city. Research materials were collected during field expeditions in August–September 2021 using generally accepted geobotanical methods. The list of higher plants found on the territory of the Gryshkiv Lis tract includes 154 species belonging to 3 classes, 51 families. The most numerous of them are Asteraceae – 19%, Poaceae – 14%, Rosaceae – 11% and Lamiaceae – 10%. There are two species of plants listed in the Red Book of Ukraine and seven species are regionally rare plants. One plant group was identified in the Green Book of Ukraine. Ecomorphic analysis of species showed that mesophytes, sciogeliophytes and mesotrophs predominate in the study area. Thus, the proportions of hygromorphs, heliomorphs and tropomorphs are close to the structure of the typical flora of the forest-steppe zone, which indicates favorable development conditions for zonal forest vegetation. However, in the spectrum of cenomorphs the share of ruderants is quite significant – almost 20%, the percentage of adventitious species is close to 3%. This indicates a significant anthropogenic transformation of the flora of the surveyed object. Habitat classification was carried out in accordance with the structure of the National Catalog of Habitats of Ukraine. Studies have shown that in the tract "Grishkiv Lis" there are at least 7 habitats, including forest (Eastern European mesophilic eutrophic deciduous forests of forest-steppe and steppe zones), swampy (reedbeds normally without freestanding water, beds of large Carex spp.), shrubbery (lowland and collinar riverine willow scrub, Central European subcontinental thickets), grassy (mesophile fringes), synanthropic (ruderal biotops of perennial nitrophilic type grasses). The dominant habitat of the Gryshkiv Lis tract is natural deciduous forests. The studied object represents a characteristic type of vegetation for the forest-steppe zone – maple-linden oak wood (anthropogenically transformed) with elements of waterlogging. Its central areas are represented by stands with a high degree of preservation of the structure and have good prospects for preservation and restoration with moderate efforts. Recommendations for the preservation of floristic diversity and vegetation of the Gryshkiv Lis tract include the introduction of a system of biotechnical measures to support ecosystems, including restrictions and regulation of recreation, elimination of natural landfills, sewage disposal and elimination of unauthorized buildings. The territory has environmental, scientific, aesthetic and recreational significance. Creation here of a protected area will help preserve the coenotic, landscape and biological diversity of Poltava region.

The Pyrogenic Archives of Anthropogenically Transformed Soils in Central Russia

Charred materials (anthracomass) stored within a soil constitute a major part of its pyrogenic archive and could provide evidence of past fire events, both natural and anthropogenic. However, the dynamics of man-made contributions to the total anthracomass of soil at different time scales are insufficiently understood. In this study, we determined the anthracomass concentrations, stocks, and particle-size distribution in anthropogenically transformed soils of different genesis and ages. Materials were collected from the following archaeological sites within Central Russia—3 Upper Paleolithic sites (Avdeevo, Khotylevo-2 and Yudinovo-1), 2 Early Iron Age settlements (Khotylevo-2 and Yaroslavl), and 1 Medieval site (Yaroslavl). Samples from different cultural layers (CLs), plough layers, and native soils (control) were studied. We identified anthracomass accumulation over a wide chronological scale starting from the Upper Paleolithic Period. The high degree of preservation of anthracomass in ancient anthropogenically transformed soils was explained by the presence of large fragments of charred bones, which are more durable in comparison to wood charcoal. The anthracomass concentrations and stocks in the Early Iron Age plough layer were lower than those in the Medieval plough layer. CLs were generally more enriched in the anthracomass than plough layers, due to their sedimentational genesis, which is more favorable for anthracomass preservation than the turbational genesis of plough layers. However, the differences between charred particle sizes in synlithogenic CLs and turbational plough layers were less clear than expected, due to the specific conditions of formation of each particular layer, e.g., burial rate, duration of ploughing, and type of agricultural land use.

Несказочная проза юганских хантов в материалах экспедиций Института филологии СО РАН

The paper deals with the existence of non-fairy prose genres, such as mythological stories, cosmogonic and etiological myths, shamanic legends, in the folklore of the modern Yugan Khanty. The Yugan Khanty have largely preserved their traditional culture and, in particular, folklore. The research materials are the texts recorded by the author during the expeditions to the Maly and Bolshoy Yugan rivers in 2013 and 2019. Five texts were studied representing the current state of the folklore genres under study in this local ethnic group of Khanty. These are mythological stories about dreams, their possible interpretations and ritual practices associated with them, about fighting forest fires with the help of “home fire,” shamanic legends about shaman’s help with illness or other problems, the legend about a monster living in a lake. These previously unpublished texts are introduced into scientific circulation, with their textual and typological analysis carried out and parallels with already published folklore texts and scientific literature on this topic drawn. The paper presents the motives of the recorded cosmogonic and etiological myths about the waterfowl that provided the land for people and the origin of a bear. The definition of what is meant by non-fairy prose is given. A conclusion is made about the relatively high degree of preservation of these genres in Yugan, and the possibility for them to be further collected, studied, and published is discussed.

Ecological-floristic characteristics of the specially protected natural area «Kostinskie Loga» (Samara Region)

The paper considers ecological-floristic characteristics of the specially protected natural area Kostinskie Loga, located in the southern part of the Samara Region (Bolshechernigovsky and Bolsheglushitsky Districts). The research area belongs to the subzone of fescue-feather grass steppes. The flora is represented by 240 species of vascular plants belonging to 160 genera, 49 families, 2 classes and 1 division. Ecological-cenotic analysis was used to assess the ecosystem diversity of the nature sanctuary. The leading groups for phytocenotic affinity are identified: steppe (65 species; 27,1%) and meadow-steppe (54 species; 22,5%), which indicates a good preservation of steppe biomes and demonstrates landscape features of the nature sanctuary. The low value of the synanthropization index (15,8%) reflects a moderate level of anthropogenic load. The adventive component of the flora is represented by 30 plant species (12,5%), among which the degree of naturalization is dominated by epecophytes (10,8%), the time of introduction by neophytes (6,7%), the methods of introduction are dominated by xenophytes (27 species; 11,3%). The analysis of flora identified 6 species included in the Black book of Central Russia (Acer negundo, Atriplex tatarica, Cyclachaena xanthiifolia, Hordeum jubatum, Elaeagnus angustifolia, Xanthium albinum). The introduction of alien plants into natural communities occurs due to pasture digression in areas bordering the territory of the nature sanctuary. In general, the degree of anthropogenic transformation of the flora in most of the territory is expressed slightly, the vegetation cover retains natural features inherent in the steppe zone. A high degree of preservation of steppe communities with a significant participation of rare representatives of flora (14,6%) creates prerequisites for the organization of one of the steppe reserve sections of the Samara Region.

Late Pleistocene and Holocene small mammal (Lipotyphla, Rodentia, Lagomorpha) remains from Medvezhyi Klyk Cave in the Southern Russian Far East

Late Pleistocene-Holocene faunal complexes of small mammals (Lipotyphla, Rodentia, and Lagomorpha) from the Russian Far East are described for the first time. We used material from the Medvezhyi Klyk Cave, located in Southern Sikhote-Alin. The numerous fossil findings from the cave display a remarkable taxonomic diversity and high degree of preservation. AMS 14C dating used for determination of deposits age. The Holocene sediments were divided into three periods: Early, Middle, and Late. The Pleistocene deposits age was not exactly determined, but under approximately estimation it can reach 50–60 ka. Thirty-nine species were found, including one member of the extinct genus of arvicolins. There are six faunal complexes identified from the studied Late Pleistocene and Holocene deposits. In general, the faunal complexes characterized by the dominance of Craseomys rufocanus within rodents, Sorex caecutiens within lipotyphlans; and relatively stability composition of most number of the dominant, codominant and subdominant species. Accordingly, the faunal complexes were described by means of two determining criteria only: relative number of species; and presence or absence of certain species. The dominant species are eurytopic and so they cannot use for reconstruction of the paleoenvironment.

Немецкие островные диалекты Томской и Новосибирской областей (на материале открытого онлайн-архива немецких диалектов Сибири)

The paper interprets the data from the open online archive of German dialects (https:// www.tomdeutsche.ru/dialects/). This work was started ten years ago in Tomsk by Prof. Z. M. Bogoslovskaya and her students. The archive provides the records of the native dialects and folklore of Russian Germans whose speech originates from different mother tongues and has different degrees of preservation. Archival materials were collected on the territory of Tomsk and Novosibirsk regions during linguistic expeditions of recent years. Many dialects of the upper German and middle German types appear to be mixed, containing (primarily in phonological terms) the features of different dialect systems, mixed as early as last century. These are secondary language formations that are exclusively spoken by older people. It is not the case in the German-Mennonite dialect (Plautdietsch), which is based on the Low German language substrate. This dialect has a higher degree of preservation and is spoken not only by older people but also by young people and children. The genre component of the collected samples of folklore and religious practices does not show much diversity. The archive contains only a few samples of songs, ditties, and jokes that old speakers can still perform in their native dialect. A special role is played by literary German – it is the language of liturgical practices, of prayers and spiritual singing. The paper presents a number of dialect material transcriptions.

Flora and vegetation features of the stow «Chalk slopes to the Proval river» (Ulyanovsk Region)

The paper contains the vegetation study results of the valuable botanical object Chalk slopes to the Proval river.The stow is located in thevicinitiesof the villageBeketovka(Veshkaymsky District of Ulyanovsk Region) and is proposed for inclusion in the regional network ofprotected areas.The data of floral and phytocenotic studies are presented.The flora of the stow Chalk slopes to the Proval river contains 287 species of vascular plants including 8 species listed in Red data book of the Russian Federation:Hedysarumgmelinii,Irisaphylla,Koeleriasclerophylla,Matthiolafragrans,Pinus cretacea[P.sylvestrisvar.cretacea],Stipapennata,S.pulcherrima,Thymusdubjanskyi[Th. cimicinusauct. p. max. p.]. The regional rare and requiring protection plants areAdonanthe vernalis,Anemone sylvestris,Asperulaexasperata,Aster alpinus,Betula krylovii,Bupleurum falcatum,Carex pediformis,Centaurearuthenica,Crepispannonica,Delphinium cuneatum,Galatellalinosyris,Galiumhexanarium,Gentianacruciata,Gentianellaamarella,Helianthemumcanum,H.nummularium,Helictotrichondesertorum,Herminiummonorchis,Jurinealedebourii,Linumflavum,L.uralense,Onosmasimplisissimas.str.,O.volgensis,Otitesbaschkirorum,Parnassiapalustris,Polygalacretacea,P.sibirica,Pulsatillapatens,Scabiosaisetensis,Schoenus ferrugineus. Calcephitic florocoenotic complex of the stow Chalk slopes to the Proval river (Ulyanovsk Region) is characterized by a mosaic of vegetation. Here, in a relatively small area, meadow, petrophytic and grass-mixed steppes, forest edges communities are presented. The floristic composition of these communities is peculiar and characterized by the presence of a large number of rare species including relict and endemic elements. In addition, in the central part of the Volga Upland, only a small amount of erosion-chalk landscapes with a high degree of preservation is known. The studied stow is recommended for inclusion in the system of protected areas of the Ulyanovsk Region.

Stratigraphic distribution, taphonomy and paleoenvironments of Spinicaudata in the Triassic and Jurassic of the Paraná Basin

Due to the chitino-phosphatic nature of Spinicaudata conchostracan exoskeletons, their carapaces exhibit a low preservational potential compared to other bivalve groups. However, the recent studies point towards the increased tolerance of the carapace against the physical processes. Due to this peculiar characteristic, conchostracan carapace have been utilized as precise temporal markers in estimating stratigraphic and taphonomic parameters. The same characteristic also makes the spinicaudatans useful in evaluating the depositional processes and environments. The present work aims at providing a paleoenvironmental and stratigraphic analysis of conchostracans (Spinicaudata) from the Triassic-Jurassic of the Paraná Basin (Santa Maria and Caturrita formations) in terms of the sedimentary facies analysis, depositional system characterization, and analysis of the taphonomic signatures of the fossiliferous horizons within these formations. The results from the taphonomic study delineates the presence of 4 distinct fossil assemblages based on the causative mechanism and fundamental characteristics of the fossil concentrations: two taphonomic assemblages in the laminated mudstone beds deposited from the decanting fine-grained sediments in floodplains; the sandstone beds with plane parallel laminations and dune- and ripple-cross-stratifications deposited from the flooding-related overflow in the floodplains; and the association of laminated mudstone and massive sandstone beds deposited as the river mouth bars. The results show that the taphonomic signatures, e.g., closed valves, may indicate the various patterns of autochthony and allochthony. In the fine-grained floodplain assemblages, the high degree of preservation can be attributed to autochthony in the conchostracans, whereas the preservational condition of floodplain sandstone sheet and mouth bar assemblages point toward parautochthony and even allochthony. Therefore, the preservational quality of conchostracan exoskeletons is likely a function of parameters, e.g., the transport duration, the distance from life position, and the magnitude of events causing their final burial. Within the observed species, the recognition of Eustheria minuta in the stratigraphic level of the Passo das Tropas creek corroborates an age for these deposits between the late Middle Triassic and early Upper Triassic. The presence of a new form, likely related to the family Fushunograptidae in sediments from the Caturrita Formation, suggests a Jurassic age for these deposits.

Macroscopic charcoal remains as evidence of wildfire from late Permian Gondwana sediments of India: Further contribution to global fossil charcoal database

Although there have been numerous reports of the occurrence of charcoal from the Indian Permian sediments (Kashmir and the Domodar Basin), here we report a new occurrence of charcoal from the Lopingian sediments of Central India, which is evidence of wildfire occurrence in the Permian of Gondwana and an addition to the global fossil charcoal database. Charcoal, a product of incomplete combustion of vegetation, is extensively reported from the Permian sediments of southern and northern hemisphere. Numerous reports have been generated from palaeobotanical and petrographical aspects of Gondwana sediments of India but the presence of macroscopic fossil charcoal has been somewhat overlooked until the past few years by many researchers, though the fusinite (charcoal equivalent term in petrographical studies) from many coalfields of Indian Gondwana has been attributed to pyrogenitic origin. Our study was carried out on macroscopic charcoal fragments retrieved from an exploratory drill core MBKW-3 from Mand-Raigarh Coalfield in the central part of the Mahanadi Basin, eastern India. The analysis involved Scanning Electron Microscopy for study of anatomical features and reflecting microscopy for estimation of the temperature of fire of charcoal formation where the inertinite reflectance data (average of 3.33%) indicate that these charcoals are formed at a temperature above 500°C. Palynomorph composition and their probable botanical affinity indicate that gymnosperms were the major type of vegetation that contributed to fuel load for wildfire while pteridophytes constituted a minor proportion. The palynological data reveal the predominance of arborescent vegetation over herbaceous elements. Fusinite reflectance data indicate that these charcoals are formed at a temperature in excess of 500°C. The almost unabraded edges of these charcoals, their high degree of preservation, and an assorted assemblage of different sizes clearly indicate their hypoautochtonous nature.

Experimental Investigation of Thermal Conductivity of Meat During Freezing

The cryogenic technologies of processing and storage of agricultural products are becoming increasingly indispensable in the food industry as an important factor of ensuring food safety. One of such technologies is the shock freezing of meat, which provides a higher degree of preservation of the quality of frozen products in comparison with traditional technologies. The thermal conductivity of meat is an important parameter influencing the energy consumption in the freezing process. This paper presents the results of an experimental investigation of the temperature dependence of the thermal conductivity of beef. The measurements were taken by using a specially designed measurement cell, which allows covering the temperature range from 80 to 300 K.

Fishes of the southeastern Brazil Atlantic Forest

The largest preserved areas of Atlantic Forest are located in the southeastern region of Brazil. Estuaries, mangroves, rivers and streams are home to a community of fish that is still poorly understood. The composition of fish species and their relationships with environmental conditions were used to identify homogeneous areas within a landscape of 33,000 km2. A total of 6,542 specimens, representing 124 species and 13 orders of bony fishes were collected at 102 sampling stations. Resulting scores from a canonical correspondence analysis applied to biological and environmental data were used in a cluster analysis to identify fish species with similar spatial distributions and localities with similar fish fauna and abiotic conditions. Five micro-regions were identified, with homogeneous compositions of species, allowing better planning of conservation of aquatic biodiversity. Despite a high degree of preservation, impacts due to deforestation, drainage of wetlands and overfishing were detected, as well as the introduction of 41 exotic species.

Interannual pteropod variability in sediment traps deployed above and below the aragonite saturation horizon in the Sub-Antarctic Southern Ocean

Anthropogenic inputs of CO2 are altering ocean chemistry and may alter the role of marine calcifiers in ocean ecosystems. Laboratory research and ocean models suggest calcifiers in polar waters are especially at risk, particularly pteropods: pelagic aragonite-shelled molluscs. However, baseline data for natural populations of pteropods are limited, especially for polar and sub-polar waters. In order to establish baseline data on diversity, preservation state and shell flux of in situ populations of Sub-Antarctic Southern Ocean pteropods, we deployed sediment traps above (1,000 m) and below (2,000 m) the aragonite saturation horizon (ASH) (currently at 1,200 m) from 1997 to 2006 at 47°S, 142°E. We identified seven pteropod taxa. We applied a shell opacity index to each shell collected and found 50% of shells collected above the ASH to be in pristine condition but only 3% of the shells collected below the ASH showed such a high degree of preservation. We estimated pteropod shell mass fluxes for the region (0.17–4.99 mg m−2 day−1), and we identified significant reductions in shell flux for Limacina helicina antarctica forma rangi and Clio recurva to the trap series above the ASH and for Limacina helicina antarctica forma rangi and Limacina helicina antarctica forma antarctica to the trap series below the ASH over the interval 1997–2006. Our data establish a temporal and vertical snapshot of the current Sub-Antarctic pelagic pteropod community and provide a baseline against which to monitor Southern Ocean pteropods responses, if any, to changing ocean conditions projected for the region in the coming decades.

Fungal diversity and deterioration in mummified woods from the ad Astra Ice Cap region in the Canadian High Arctic

Non-permineralized or mummified ancient wood found within proglacial soil near the ad Astra Ice Cap (81°N, 76°W), Ellesmere Island, Canada was investigated to ascertain the identification of the trees, current morphological and chemical characteristics of the woods and the fungi within them. These woods, identified as Betula, Larix, Picea and Pinus, were found with varying states of physical and chemical degradation. Modern microbial decomposition caused by soft rot fungi was evident and rDNA sequencing of fungi obtained from the samples revealed several species including Cadophora sp., Exophiala sp., Phialocephala sp., as well as others. Analytical 13C-labeled tetramethylammonium hydroxide thermochemolysis showed the lignin from the ancient wood was in a high degree of preservation with minor side chain alteration and little to no demethylation or ring hydroxylation. The exposure of these ancient woods to the young soils, where woody debris is not usually prevalent, provides carbon and nutrients into the polar environment that are captured and utilized by unique decay fungi at this Arctic site.

Nanostructure of the aqueous form of lung surfactant of different species visualized by cryo‐transmission electron microscopy

Cryogenic temperature transmission electron microscopy (cryo-TEM) makes it possible to study the nanostructure of a wide range of fluid phases with a high degree of preservation. Most studies based on scanning electron microscopy or TEM employ specimen preparation techniques that give extraordinary results for tissues, but alter the native structure of complex fluid substances such as lung surfactant. In this paper, we evaluated direct-imaging cryo-TEM as a method to study the morphology of the aqueous form of lung surfactant. We compared the morphology of samples obtained from different species, and cryo-TEM data to data obtained by staining-and-drying. We demonstrate that cryo-TEM preserves and images much better sample morphology and fine details of the surfactant structures. We show that cryo-TEM, a method based on physical fixation, which avoids chemical changes and aggregate rearrangement, is a most useful tool to further our understanding of lung surfactant and its function.

Provenance and diagenesis of organic matter in Late Cretaceous and Tertiary sediments from the southern Black Sea margin

The organic matter in the Late Cretaceous and Tertiary sediments from the southern Black Sea margin is assigned to the terrestrial-marine/terrestrial range of organic facies. Within this range, the stratigraphic section yields different organic facies types in response to different accumulation and preservation controlling processes. During the Late Companian-Maastrichtian, organic material from the shelf and slope was re-deposited in the deeper oxic parts of the basin. Rapid transport and sedimentation resulted in a higher degree of preservation of lipid-rich, terrestrial components (sporinite, cutinite, resinite) in comparison to the autochthonous sediments. The increase in organic carbon with increasing silt/clay content together with low carbon concentrations in the allochthonous sediments suggest that the accumulation of organic matter in the source areas was controlled by terrigenous influx and that the accumulation conditions were not favorable.