scholarly journals Aneuploids in the shrub birch Betula humilis populations in Poland

2011 ◽  
Vol 80 (3) ◽  
pp. 233-235 ◽  
Author(s):  
Katarzyna A. Jadwiszczak ◽  
Ewa Jabłońska ◽  
Stanisław Kłosowski ◽  
Agata Banaszek
Keyword(s):  
Vegetative Reproduction ◽  
Congeneric Species ◽  
High Frequencies ◽  
Karyotype Instability ◽  
Northeastern Poland ◽  
Glacial Relict ◽  
Betula Humilis ◽  
Range Fragmentation

Shrub birch (<em>Betula humilis </em>Schrk.) is endangered glacial relict growing in natural and drained fens and transitional mires. At present study we examined karyotypes of 103 individuals of <em>B. humilis</em>, collected in six populations from eastern and northeastern Poland. We found 60% of diploid individuals with 2n = 28. The rest of studied plants were aneuploids with 26, 27, 29, 30 and 31 chromosomes in their karyotypes. High frequencies of aneuploids in Polish populations of <em>B. humilis </em>could be a consequence of: (i) hybridization with congeneric species, (ii) stress resulting from range fragmentation, (iii) karyotype instability of individuals with 2n ≠ 28, or (iv) vegetative reproduction.

scholarly journals Disappearing population of Betula humilis Schrk. on the Maliszewskie Lake, NE Poland

2015 ◽  
Vol 37 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Agnieszka Chrzanowska ◽  
Katarzyna A. Jadwiszczak
Keyword(s):  
Bird Species ◽  
Lake Area ◽  
Ne Poland ◽  
North Eastern ◽  
Distinct Individual ◽  
Declining Populations ◽  
Nuclear Microsatellite ◽  
Glacial Relict ◽  
Betula Humilis ◽  
Single Cluster

Abstract Betula humilis Schrk. is an endangered glacial relict inhabiting wet meadows, natural and drained fens. One of its declining populations is located on the Maliszewskie Lake (the Wizna swamp, north-eastern Poland). The goal of the present study was to estimate the number of B. humilis individuals in this locality. In the Maliszewskie Lake population, 59 ramets, grouped into three clusters, were found. Twelve nuclear microsatellite loci were chosen to genotype 52 ramets. The analysis revealed that all the shoots within the single cluster had the same genotypes at the loci considered. This means that each cluster constituted one genetically distinct individual; thus, there were only three individuals of B. humilis in the studied population. The maintenance of the B. humilis population in the Maliszewskie Lake area requires urgent active protection involving removal of the shading vegetation. In fact, the entire Maliszewskie Lake is worthy of protection because of its hitherto unexplained origin and the occurrence of many endangered bird species.

Quasi-Periodic Oscillations in Dwarf Novae

1979 ◽  
Vol 46 ◽  
pp. 77-88
Author(s):  
Edward L. Robinson
Keyword(s):  
Binary Systems ◽  
Outer Edge ◽  
Light Curves ◽  
Close Binary ◽  
Bright Spot ◽  
Dwarf Novae ◽  
Periodic Oscillations ◽  
High Frequencies ◽  
Short Period ◽  
Typical Time

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.

TBE in Poland

2019 ◽  
Author(s):  
Katarzyna Pancer ◽  
Włodzimierz Gut
Keyword(s):  
World War Ii ◽  
Typhoid Fever ◽  
Clinical Symptoms ◽  
World War ◽  
Tick Borne Encephalitis ◽  
Northeastern Poland

Clinical symptoms of tick-borne encephalitis (TBE) were first described in Poland in 1948 by Demiaszkiewicz. All patients had been living in the Białowieża region (in northeastern Poland). Similar infections were described to those that had been diagnosed in the same region before World War II as complicated cases of typhoid fever or influenza.

TBE in Poland

2020 ◽  
Keyword(s):  
World War Ii ◽  
Typhoid Fever ◽  
Clinical Symptoms ◽  
World War ◽  
Tick Borne Encephalitis ◽  
Northeastern Poland

Clinical symptoms of tick-borne encephalitis (TBE) were first described in Poland in 1948 by Demiaszkiewicz. All patients had been living in the Białowieża region (in northeastern Poland). Similar infections were described to those that had been diagnosed in the same region before World War II as complicated cases of typhoid fever or influenza.1

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