Mid- to Late Holocene elemental record and isotopic composition of lead in a peat core from Wolbrom (S Poland)

Peat Core W3 was taken from the fen in Wolbrom (Silesian-Cracovian Upland, Southern Poland) in September 2015. Previous analyses of Core W3 showed a significant increase in lead concentration during the time of the Roman Empire as well as some changes in peat accumulation conditions. The work reported here investigates its geochemical composition in terms of major and trace elements (Pb, Zn, Na, K, Ca, Fe, Mg, Mn, Cu, Ni, Cr by AAS) as well as Pb isotopic composition, to identify the sources of metal pollution in the Wolbrom peat deposit. The geochemical record spans the period from 4900 BC to modern times, with a likely hiatus corresponding to the period from the Middle Ages to the beginning of the contemporary metallurgical industry. The Pb isotopic composition combined with a cluster analysis allows identification of the primary sources of Pb. In addition, Principal Component Analysis (PCA) helps to decipher the most important factors that affected the chemical composition of sediments at Wolbrom. These factors were linked to chemical denudation and human activity

Calcium ion currents mediating oocyte maturation events

During maturation, the last phase of oogenesis, the oocyte undergoes several changes which prepare it to be ovulated and fertilized. Immature oocytes are arrested in the first meiotic process prophase, that is morphologically identified by a germinal vesicle. The removal of the first meiotic block marks the initiation of maturation. Although a large number of molecules are involved in complex sequences of events, there is evidence that a calcium increase plays a pivotal role in meiosis re-initiation. It is well established that, during this process, calcium is released from the intracellular stores, whereas less is known on the role of external calcium entering the cell through the plasma membrane ion channels. This review is focused on the functional role of calcium currents during oocyte maturation in all the species, from invertebrates to mammals. The emerging role of specific L-type calcium channels will be discussed

Proposed Standards for Medical Education Submissions to the Journal of General Internal Medicine

To help authors design rigorous studies and prepare clear and informative manuscripts, improve the transparency of editorial decisions, and raise the bar on educational scholarship, the Deputy Editors of the Journal of General Internal Medicine articulate standards for medical education submissions to the Journal. General standards include: (1) quality questions, (2) quality methods to match the questions, (3) insightful interpretation of findings, (4) transparent, unbiased reporting, and (5) attention to human subjects’ protection and ethical research conduct. Additional standards for specific study types are described. We hope these proposed standards will generate discussion that will foster their continued evolution

A skeleton of peat-trapped forest rhinoceros Stephanorhinus kirchbergensis (Jäger, 1839) from Gorzów Wielkopolski, Northwestern Poland: a record of life and death of the Eemian large mammals

We present a description of an almost complete skeleton of the forest rhino (Stephanorhinus kirchbergensis) found near Gorzów Wielkopolski (Northwest Poland) in its geological and palaeoenvironmental context. While finds of bones and teeth are common, the importance of this find resides in, that it is the most complete specimen of this species, almost perfectly preserved in a well-studied and dated stratigraphic and sedimentological context, along with other fossil fauna and flora. The OSL dates of glaciofluvial sediments sandwiching skeleton-bearing horizons indicate a Middle Eemian age of the Pleistocene paleolake land. This warm climate is also indicated by the results of sedimentological, geochemical, paleobotanical, and isotopic analyses. The rhino skeleton was deposited in a shallow area near the lake’s littoral zone. Bite marks of a large predator (cave hyena) were recognized on the rhino’s pelvis, which, due to their location, were probably created post-mortem. With an estimated height of 1.82 m at the withers, this was a large adult Stephanorhinus kirchbergensis. The results of osteometric analyses indicate that we are dealing with one of the largest known individuals of this species. Although it suffered from a pathologically deformed spine, the individual died at a relatively old age.Peer reviewe

Enforcing Multifunctionality: A Pressure-Induced Spin-Crossover Photomagnet

Photomagnetic compounds are usually achieved by assembling preorganized individual molecules into rationally designed molecular architectures via the bottom-up approach. Here we show that a magnetic response to light can also be enforced in a nonphotomagnetic compound by applying mechanical stress. The nonphotomagnetic cyano-bridged Fe^II–Nb^IV coordination polymer {[Fe^II(pyrazole)₄]₂[Nb^IV(CN)₈]·4H₂O}_<i>n</i> (<b>FeNb</b>) has been subjected to high-pressure structural, magnetic and photomagnetic studies at low temperature, which revealed a wide spectrum of pressure-related functionalities including the light-induced magnetization. The multifunctionality of <b>FeNb</b> is compared with a simple structural and magnetic pressure response of its analog {[Mn^II(pyrazole)₄]₂[Nb^IV(CN)₈]·4H₂O}_<i>n</i> (<b>MnNb</b>). The <b>FeNb</b> coordination polymer is the first pressure-induced spin-crossover photomagnet

Study of genetic similarity between parental forms of maize hybrid lines using molecular markers of SSR

Programy hodowlane kukurydzy koncentrują się na otrzymaniu odmian mieszańcowych wykazujących jak najwyższy efekt heterozji. Wielu badaczy przypisuje zależność tego efektu od dystansu genetycznego form wyjściowych przy uwzględnieniu ich pochodzenia. Uważa się, że im mniej podobne genetycznie do siebie są linie wyjściowe, tym większy efekt heterozji generują ich mieszańce F₁. Narzędziem umożliwiającym grupowanie linii wsobnych oraz wyznaczanie dystansu genetycznego między nimi są markery molekularne. Materiałem roślinnym użytym do badań były 94 linie wsobne kukurydzy z Hodowli Roślin Smolice Spółka z o.o. oraz w Małopolskiej Hodowli Roślin. W wyniku przeprowadzonych badań wykazano użyteczność markerów molekularnych SSR do podziału genotypów grupy podobieństwa oraz do wyznaczania dystansu genetycznego między liniami wsobnymi kukurydzy. Dystans genetyczny wyznaczony w oparciu o markery molekularne mieścił się w zakresie od 48% do 97%. Dystans między liniami wsobnymi kukurydzy ustalony na podstawie wielkości analizowanych cech struktury plonu wahał się w zakresie od 86% do 99%.Breeding programs focus on obtaining hybrid varieties with the greatest heterosis effect, by which significant higher yields can be achieved through appropriate selection of parent components. Many researchers assign the height of this effect to the genetic distance of the initial forms, taking into account their origin. It is believed that the less similar lines are the output lines, the greater the effect of heterosis generates their hybrids F₁. Therefore, methods are sought that would allow for the initial selection of lines for heterosis crosses based on their genetic material. The molecular markers are a tool for grouping inbred lines into groups and for determining the genetic distance between them. Individual marker systems differ in amplified DNA regions and the number of polymorphic bands generated, and thus accuracy. The plant material used for the study were 94 inbred lines of maize from the Plant Breeding Smolice and Malopolska Plant Breeding. As a result of the studies, the usefulness of SSR molecular markers for the division of genotypes into groups and the determination of genetic distance between maize inbred lines have been demonstrated. The genetic distance determined by 20 pairs of SSR primers ranged from 48% to 97% and the genotypes were divided into five groups of similarities. The lines that shared the greatest distance in most cases came from the same breeding company. The distances determined on the basis of yield structure traids ranged from 86% to 99% and the genotypes were divided into two groups of similarities. Genetic diversity calculated by Nei and Li showed greater variability than phenotypic differences expressed by Euclidean distances. The distances between objects at the phenotypic level ranged from 0.01 to 0.37, with an average value of 0.11. In contrast, the molecular variation was from 0.027 to 0.778, with an average value of 0.35. Both molecular analyzes and analysis of yield characteristics allowed the identification of similarity groups between the analyzed lines, most of which were grouped according to their origin

Reconstruction of atmospheric lead and heavy metal pollution in the Otrêbowskie Brzegi peatland (S Poland)

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