Optical density of Scots pine wood and climatic conditions in Toruń, Poland

The aim of the studies was to evaluate the usefulness of the microscopic features of wood in characterising the climatic conditions of a period for which only proxy data are available. Samples were taken from historical wood from Koronowo collegiate church and from a living Scots pine tree growing in the Toruń-Wrzosy site. All measurements were performed using ImageJ software. The dendroclimatological analysis was carried out in the program DendroClim2002. The results show a correlation between the microscopic features of wood and climatic conditions. For the period 1951–2000 the maximum optical density of pine wood depends on average May air temperature and June precipitation, with correlation coefficients of -0.32 and -0.29, respectively. A similar correlation was found for mean maximum and minimum temperatures in May; -0.35 and -0.37, respectively. Additional correlations between selected meteorological elements and the maximum optical density of the wood were found using 30-year moving averages and moving intervals

Ecological drift and competitive interactions predict unique patterns in temporal fluctuations of population size

Recent studies have highlighted the importance of higher-order competitive interactions in stabilizing population dynamics in multi-species communities. But how does the structure of competitive hierarchies affect population dynamics and extinction processes? We tackled this important question by using spatially explicit simulations of ecological drift (10 species in a homogeneous landscape of 64 patches) in which birth rates were influenced by interspecific competition. Specifically, we examined how transitive (linear pecking orders) and intransitive (pecking orders with loops) competitive hierarchies affected extinction rates and population dynamics in simulated communities through time. In comparison to a pure neutral model, an ecological drift model including transitive competition increased extinction rates, caused synchronous density-dependent population fluctuations, and generated a white-noise distribution of population sizes. In contrast, the drift model with intransitive competitive interactions decreased extinctions rates, caused asynchronous (compensatory) density-dependent population fluctuations, and generated a brown noise distribution of population sizes. We also explored the effect on community stability of more complex patterns of competitive interactions in which pairwise competitive relationships were assigned probabilistically. These probabilistic competition models also generated density-dependent trajectories and a brown noise distribution of population sizes. However, extinction rates and the degree of population synchrony were comparable to those observed in purely neutral communities. Collectively, our results confirm that intransitive competition has a strong and stabilizing effect on local populations in species-poor communities. This effect wanes with increasing species richness. Empirical assemblages characterized by brown spectral noise, density-dependent regulation, and asynchronous (compensatory) population fluctuations may indicate a signature of intransitive competitive interactions

River Regulation Causes Rapid Changes in Relationships Between Floodplain Oak Growth and Environmental Variables

The radial growth of pedunculate oak (Quercus robur), a species often ecologically dominating European deciduous forests, is closely tied up with local environmental variables. The oak tree-ring series usually contain a climatic and hydrologic signal that allows assessing the main drivers of tree growth in various ecosystems. Understanding the climate-growth relationship patterns in floodplains is important for providing insights into the species persistence and longevity in vulnerable riverine ecosystems experiencing human-induced hydrology alteration. Here, we use 139 years long instrumental records of local temperature, precipitation, and water levels in the Dnipro River in Kyiv to demonstrate that the implementation of river regulation has decoupled the established relationship between the radial growth of floodplain oak and local hydro-climatic conditions. Before the river flow has been altered by engineering modifications of 1965–1977, the water level in the Dnipro River was the key driver of oak radial growth, as reflected in the tree-ring width and earlywood width. The construction of two dams has altered the seasonal distribution of water level diminishing the positive effect of high water on oak growth and subsequently reversing this trend to negative, resulting from a seasonal ground water surplus. The decrease in the correlation between oak growth indices and the river’s water level in April–June was unprecedentedly rapid and clearly distinguishable among other changes in the growth-to-climate relationship. Our findings further demonstrate that trees growing in areas exposed to urban development are the most susceptible to downside effects of river regulation

Droughts in the area of Poland in recent centuries in the light of multi-proxy data

The history of drought occurrence in Poland criteria used were those proposed by McKee et al. (1993) and in the last millennium is poorly known. To improve this modified for the climate conditions of Poland by Lab˛edzki knowledge we have conducted a comprehensive analysis us (2007). ing both proxy data (documentary and dendrochronological) More than 100 droughts were found in documen and instrumental measurements of precipitation. The paper tary sources in the period 1451–1800, including 17 presents the main features of droughts in Poland in recent megadroughts. A greater than average number of droughts centuries, including their frequency of occurrence, cover were observed in the second halves of the 17th century and age, duration, and intensity. The reconstructions of droughts the 18th century in particular. Dendrochronological data con based on all the mentioned sources of data covered the pe firmed this general tendency in the mentioned period. riod 996–2015. Examples of megadroughts were also cho Analysis of SPI (including its lowest values, i.e. droughts) sen using documentary evidence, and some of them were de showed that the long-term frequency of droughts in Poland scribed. has been stable in the last two or three centuries. Extreme Various documentary sources have been used to identify and severe droughts were most frequent in the coastal part droughts in the area of Poland in the period 1451–1800 and of Poland and in Silesia. Most droughts had a duration of 2 to estimate their intensity, spatial coverage, and duration. months (about 60 %–70 %) or 3–4 months (10 %–20 %). Fre Twenty-two local chronologies of trees (pine, oak, and fir quencies of droughts with a duration of 5-or-more months from Poland were taken into account for detecting nega were lower than 10 %. The frequency of droughts of all cat tive pointer years (exceptionally narrow rings). The delimita egories in Poland in the instrumental period 1722–2015 was tion of droughts based on instrumental data (eight long-term greatest in winter, while in the documentary evidence (1451– precipitation series) was conducted using two independent 1800) droughts in this season are rarely mentioned. approaches (Standard Precipitation Index, SPI, calculated for The occurrence of negative pointer years (a good proxy for 1-, 3-, and 24-month timescales, and a new method proposed droughts) was compared with droughts delimited based on by authors). For delimitation of droughts (dry months), the documentary and instrumental data. A good correspondence was found between the timing of occurrence of droughts identified using all three kinds of data (sources)

Differences in the Climate-Growth Relationship of Scots Pine: A Case Study from Poland and Hungary

Scots pine is an adaptable and prevalent European tree species that grows naturally throughout Europe and has been planted in a wide range of environments. Previous studies have indicated that climatic variables affect tree-ring growth patterns in this species, but it is also possible that certain aspects of the growth environment moderate this response. In order to understand the potential impact a shifting climate has on this important species, this study compared the growth response of two populations of Scots pine. Trees from similar bioclimatic regions in Hungary and Poland were compared using the hypothesis that differences in the association between climate and growth would be reflected by the degree of tree-ring width variation. We also wanted to know how changing climatic conditions influenced the temporal stability of the climate–growth signal in the most important periods for tree growth. Clear similarities in the effect of temperature and precipitation on tree-ring width variation were found between the two sites, but there were also some interesting differences. In the late winter to early spring period both populations reacted to warming with a decreasing association with temperature. Summer precipitation was shown to be the dominant factor in controlling ring-width. A decreasing trend in summer precipitation values at both Hungarian and Polish sites resulted in a weakening in correspondence for the Hungarian trees, while the Polish trees showed a significant increase in correlation with summer precipitation. The results indicated that changes in climate influenced the studied trees in different ways which has implications for the future balance of Scots pine growth in Europe

Blood Pressure Decrease Analysis After the First Dose of Perindopril or Trandolapril in Acute Myocardial Infarction Patients

Wstęp Inhibitory konwertazy angiotensyny I stały się w ostatnich latach niezmiernie ważną grupą leków w terapii chorób układu sercowo-naczyniowego. Przeprowadzone badania kliniczne dowiodły istotnych korzyści z zastosowania tej klasy leków u pacjentów we wczesnej fazie zawału serca. Uzasadniona jednak wydaje się obawa przed nadmiernym obniżeniem ciśnienia tętniczego po podaniu pierwszej dawki leku, szczególnie w wybranych podgrupach chorych wysokiego ryzyka. Celem pracy była ocena spadków zarówno ciśnienia tętniczego skurczowego (SBP), jak i rozkurczowego (DBP) przeprowadzona na podstawie analizy średniej różnic między kolejnymi średnimi jednogodzinnymi i wartością wyjściową pierwszej średniej jednogodzinnej w grupie kontrolnej i w grupie leczonej perindoprilem lub trandolaprilem. Materiał i metody Badanie przeprowadzono wśród 107 chorych spełniających kryteria ostrego zawału serca, z których 40 stanowiło grupę kontrolną, 32 chorych leczono perindoprilem i 35 - trandolaprilem. Dwudziestoczterogodzinne monitorowanie ciśnienia tętniczego wykonano w 1, 2 lub 3 dobie ostrego zawału serca. Wyniki W przeprowadzonym badaniu stwierdzono silniejsze działanie hipotensyjne perindoprilu w zakresie SBP, natomiast trandolaprilu - w zakresie DBP, w 1 dobie stosowania u chorych w ostrej fazie zawału serca. Mimo istotnego obniżenia SBP po podaniu pierwszej dawki inhibitora ACE nie zaobserwowano nadmiernej reakcji hipotensyjnej w badanych grupach. Zarówno maksymalne średnie spadki SBP, jak i częstość incydentów obniżenia SBP o ponad 20 mm Hg w badanych grupach były zbliżone do grupy kontrolnej. Uzasadniona wydaje się konieczność monitorowania ciśnienia w 1 dobie stosowania tej klasy leków u chorych w ostrej fazie zawału serca, ze względu na możliwość dość znacznego obniżenia ciśnienia tętniczego po podaniu pierwszej dawki długodziałającego inhibitora ACE.Background Angiotensin converting enzyme inhibitors became very important therapeutic agents in the treatment of cardiovascular diseases in the recent years. Several clinical trials confirmed significant benefits of the early use of ACE inhibitors in acute myocardial infarction patients. However reasonable is apprehension for potential risk of the first dose hypotension specially in selected groups of high risk patients. The objective of this study was to evaluate decrease of systolic and diastolic blood pressure in the analysis of mean difference between subsequent mean one hour blood pressure and initial one hour blood pressure in control group and group treated with perindopril or trandolapril. Material and methods Study was conducted in 107 acute myocardial infarction patients, control group consisted of 40 patients, 32 were treated with perindopril and 35 with trandolapril. 24-hour blood pressure monitoring was performed in the 1, 2 or 3rd day of the acute myocardial infarction. Results Despite significant systolic blood pressure decrease after the first dose of ACE inhibitor we have not observed excessive hypotensive reaction in studied groups. Mean maximal systolic blood pressure decrease and frequency of hypotensive effect exceeding 20 mm Hg in treated groups was similar in comparison to control group. We have perceived greater hypotensive effect after the first dose of perindopril on systolic blood pressure and trandolapril on diastolic blood pressure in studied groups. Conclusion There was no significant differences in mean maximal blood pressure decrease after the first dose of perindopril or trandolapril in acute myocardial infarction patients

Anthropogenic forcing increases the water-use efficiency of African trees

Rising atmospheric CO2 concentrations affect climate directly through radiative effects and indirectly by changing plant water-use efficiency. Under global warming scenarios these widely reported changes will have a substantial impact on future bush encroachment, crop yields, river flow and climate feedbacks. Tree-ring intrinsic water-use efficiency (iWUE) records for Africa show a 24.6% increase over the 20th century. As high iWUE can partly counterbalance projected decreases in regional precipitation, this research has important implications for those involved in water resource management and highlights the need for climate models to take physiological forcing into account.National Geographic Society - Science and Exploration Europe (grant GEFNE80-13), the Royal Geographical Society, the Quaternary Research Association, the Palaeo-Anthropological Scientific Trust, the National Research Foundation, SysTem for Analysis, Research and Training (START) and the Climate Change Consortium of Wales.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-14172017-05-31hb2016Mammal Research Institut

Pacjentka z kardiomiopatią przerostową zawężającą drogę odpływu lewej komory leczona ablacją alkoholową

Kardiomiopatia przerostowa charakteryzuje się nieproporcjonalnym do obciążenia hemodynamicznego, uwarunkowanym genetycznie, niesymetrycznym przerostem mięśnia sercowego dotyczącym głównie lewej komory, a w szczególności przegrody międzykomorowej. Ponieważ kardiomiopatię przerostową uważa się za najczęstszą chorobę serca uwarunkowaną genetycznie, a także z powodu związanego z nią zwiększonego ryzyka nagłej śmierci sercowej, stanowi ona wciąż przedmiot żywej dyskusji. Echokardiografia nadal pozostaje najważniejszym badaniem w diagnostyce tej choroby. Choć kardiomiopatia przerostowa nie ujawnia żadnych swoistych zmian w EKG, obserwacje potwierdzają, że badanie to jest powszechnie dostępnym narzędziem pozwalającym na wyodrębnienie z populacji już wczesnej postaci choroby wtedy, gdy brakuje klinicznych danych do jej rozpoznania. W zależności od objawów klinicznych choroby zaleca się różne podejście do pacjentów. Chorzy bez objawów wymagają jedynie długotrwałej obserwacji. Niezależnie od wielkości gradientu w drodze odpływu lewej komory farmakoterapia jest powszechnie zalecanym leczeniem pierwszego rzutu u większości chorych. Dolegliwości skutecznie łagodzą β-adrenolitykami lub werapamil. W przypadku wyczerpania możliwości farmakologicznej kontroli objawów choroby sięga się po inwazyjne metody leczenia. Ostatnio coraz większe znaczenie ma przezskórna ablacja alkoholowa jako metoda o mniejszym stopniu inwazyjności. Wszczepienie kardiowertera-defibrylatora zaleca się chorym z utrwalonym częstoskurczem komorowym, migotaniem komór lub obciążonym dużym czynnikiem ryzyka nagłej śmierci sercowej. Pacjenci z kardiomiopatią powinni być informowani o niebezpieczeństwie wystąpienia choroby wśród członków ich rodzin. Krewnych pierwszego stopnia, a także pozostałych spokrewnionych członków rodziny należy zachęcać do poddania się badaniom przesiewowym