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1

Clearing the fog: Changes in T2 relaxation time after stroke reflect clearing processes

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Kranz A., Deten A., Haertig W., Boltze J., Wagner D. C.
Acta Neurobiologiae Experimentalis
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2013
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tom 73
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nr 1
CT and MR imaging techniques are frequently used for the diagnosis and progress monitoring of ischemic stroke in clinical practice and research. After stroke, both methods are characterized by a transient pseudo-normalized imaging signal, the so-called fogging phenomenon. This study evaluates potential pathophysiological changes associated with fogging, as well as its influence on the correct determination of the ischemic lesion in a rat stroke model. Male spontaneously hypertensive rats were subjected to permanent middle cerebral artery occlusion. Ischemic lesion volume, brain edema and grey scale value spread within the ischemic lesion were determined on T2-weighted MR sequences at days 1, 4, 8, 11 and 29 after stroke onset, and compared with immunohistochemistry for astrogliosis, microglia/macrophage infiltration and angiogenesis. All animals showed MR fogging at days 4, 8 and 11 after stroke. The transient normalization of T2 signals occurred independently from the development of infarct volumes, but coincided well with the spatio-temporal occurrence of necrosis, angiogenesis and microglia/macrophage infiltration. Our results suggest that the fogging effect reflects the clearance of necrotic tissue within the ischemic lesion and is thus not relevant for the determination of the lesion volume.
2

Bats select buildings in clearings in Bialowieza Primeval Forest

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Mazurska K., Ruczynski I.
Acta Chiropterologica
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2008
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tom 10
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nr 2
Species dominance structure and selection of buildings by bats were studied during the breeding season in areas surrounding the well-preserved stands of Białowieża Primeval Forest (BPF), potentially offering an abundance of tree cavities. Searches for bats were carried out during daylight hours and at evening emergence. Thirty eight of the 238 buildings surveyed from May to August, 2002 were used by 708 bats. Only three of the 12 resident species of bats occupied buildings, amongst these Vespertilio murinus and Eptesicus serotinus were the most common, found in 16 and 15 buildings, respectively. Pipistrellus pygmaeus was located in two buildings. This suggests that limited access to old-growth forests (potentially rich in tree cavities) may not be a crucial factor leading to the occupation of buildings by those species. Selection of buildings by bats was further investigated by comparing 14 characteristics of those buildings occupied by bats to those unused. Six of these characteristics were shown to have a significant influence. Using Akaike's Information Criterion (AICc), the most important categories for selection were roof lining and building size. This would suggest that the criterion for the selection of buildings by these species is based not only on its location but on these key structural attributes.
3

Effects of deforestation on structure and diversity of small mammal communities in the Moravskoslezske Beskydy Mts [Czech Republic]

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Bryja J., Heroldova M., Zejda J.
Acta Theriologica
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2002
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tom 47
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nr 3
During 1970s and 1980s, a large area of mountains in the Czech Republic was influenced by long-term industrial air pollution. Among the most degraded areas were the peaks of the Moravskoslezske Beskydy Mts, where vast clearings resulted from emissions and subsequent forest destruction. This study is aimed at determining the degree of deforestation that is necessary to cause changes in structure and species diversity of small mammal communities that were observed previously. Communities of rodents and insectivores were monitored for a minimum of 3 years at two mountain ranges of the Moravskoslezske Beskydy Mts (Czech Republic) by standard mouse snap-traps. The localities (Smrk and Knehyne) differ by the degree of human dis­turbance. Clearings on Smrk Mt are very large (> 30 ha) with no remaining original forest growth as a result of intensive air pollution, unlike the same habitat type at Knehyne Mt, where the clearings are minor (< 3 ha) and contain living solitary trees. Structure and diversity of small mammal communities in clearings were compared with those from original forests and other mountain habitats. Communities of small mammals at clearings in Smrk Mt (with dominating Microtus agrestis) are structurally very different from all other habitats, while structure of communities at Knehyne clearings are very similar to those of original mountain forest (Complete linkage clustering based on Renkonen index). The community of the original mountain spruce forest at Knehyne had the highest species diversity (according to Shannon-Weaver, Brillouin, and Simpson indices, Shannon evenness, and rarefaction), while species diversity at clearings of Smrk was the lowest. Shannon diversity of community at Knehyne primeval forest is similar to that of Knehyne clearings, while at Smrk Mt the forest diversity is higher than that of clearings. The species diversity of mountain forest and clearings at Knehyne Mt was significantly higher than that in the same habitats at Smrk Mt. Our results obtained in disturbed habitats at Knehyne and Smrk Mts suggest that the degree of deforestation may influence the presence and/or the degree of community changes. If the forest destruction is relatively small (clearings < 3 ha), the structure and diversity of small mammal communities do not differ from those of original forest.
4

The micromosaic structure of the ground layer vegetation in thirty-four chosen plots of Bialowieza Forest in North-Eastern Poland

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Bobiec A.
Fragmenta Floristica et Geobotanica
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1994
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tom 39
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nr 2
5

Powiekszajmy drzewostan lesny

70%
Bugno F.
Biuletyn Informacyjno-Handlowy. Ośrodek Doradztwa Rolniczego Boguchwała
|
2001
|
nr 10
12
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