Pines influence hydrophysical parameters and water flow in a sandy soil

Pines, used for sand dune stabilization, can influence the hydrophysical parameters and water flow in an aeolian sandy soil considerably, mainly due to soil water repellency. Two sites, separated by distance of about 20 m, formed the basis of our study. A control soil (“Pure sand“) with limited impact of vegetation or organic matter was formed at 50 cm depth beneath a forest glade area. This was compared to a “Forest soil” in a 30-year old Scots pine (Pinus sylvestris) forest. Most of the hydrophysical parameters were substantially different between the two soil surfaces. The forest soil was substantially more water repellent and had two-times the degree of preferential flow compared to pure sand. Water and ethanol sorptivities, hydraulic conductivity, and saturated hydraulic conductivity were 1%, 84%, 2% and 26% those of the pure sand, respectively. The change in soil hydrophysical parameters due to soil water repellency resulted in preferential flow in the forest soil, emerging during a simulated heavy rain following a long hot, dry period. The wetting front established in pure sand exhibited a form typical of that for stable flow. Such a shape of the wetting front can be expected in the forest soil in spring, when soil water repellency is alleviated substantially.     

The in vitro reconstitution of rough endoplasmic reticulum membrane derived from human placenta

The isolation of rough endoplasmic reticulum from human placenta is described. Puromycin facilitated the detachment of the majority of the ribosomes from the membrane. Ribosomes could be re-attached to the stripped membrane, and puromycin was also necessary for detaching the rebound ribosomes, indicating that peptidyl-tRNA anchors the ribosomes to the membrane in both the native and the reconstituted rough membrane. Peptides labeled in-vitro on membrane bound ribosomes (native and reconstituted rough membrane) remained associated with the membrane after the ribosomes were detached. A protein with an electrophoretic mobility in SDS gels identical to that of HPL is among the membrane associated nascent proteins of the native and the reconstituted rough membrane.     

Experiment with Split-Plot Generated by PBIB Designs

The paper refers to the construction of two-factor experiments carried out in incomplete split-plot design in which levels of both factors occur as treatments in PBIB designs. It presents also the analysis of variance of these experiments based on partial analyses in the so called strata. These strata are connected with the variability between subplots inside wholeplots, between the wholeplots inside blocks and between blocks inside the total experiment.     

Polyelectrolytes,thirty years later

This contribution contains a personal account of the early days of polyelectrolyte research, a discussion of the configurational properties of polyelectrolyte chains, a brief review of polyetectrolyte theories and some remarks concerning recent experimental and theoretical developments as well as future trends.     

Caching prey in trees by Eurasian lynx

Two cases of Eurasian lynxLynx lynx (Linnaeus, 1758) caching prey (roe deerCapreolus capreolus) in trees were documented: in southeastern Poland in February 1996 and in southwestern Czech Republic in November 1999. Both carcasses were placed on trees in an identical way.     

Fluctuating ungulate density shapes tree recruitment in natural stands of the Białowieża Primeval Forest,Poland

Question: What are the main driving factors in 70 years of natural dynamics in tree recruitment in the Bia?owie?a National Park? Location: Bia?owie?a National Park, Poland, is one of the least disturbed temperate, lowland forest systems in Europe. Methods: We tested whether fluctuations in large herbivore populations, changes in climate and openness of the forest explained compositional dynamics. Tree recruitment (to size class DBH≥5 cm) was measured on permanent transects (in total, 14.9 ha) six times between 1936‐2002. These data were related to existing data on ungulate density, climatic parameters and estimates of forest openness collected during the same period. Results: Total recruitment of all tree species combined was negatively correlated with total ungulate density and red deer density. The variation in response between species was related to the preferences of herbivores; the more preferred forage species (especially Carpinus betulus) were positively and the less preferred species negatively related to herbivore density. Total tree recruitment rates were not related to climatic parameters and openness of the forest. Only Alnus glutinosa recruitment was significantly related to climatic parameters, and Ulmus glabra related to forest openness, but there were no predictable patterns in recruitment among species in relation to these factors. Conclusion: The present study indicated that changes in large herbivore density have played an important role in driving patterns in tree recruitment and species composition during the last 70 years in Bia?owie?a National Park. In contrast to other studies, increasing herbivore numbers were associated with higher recruitment of preferred and browsing‐tolerant species. Periodical crashes in ungulate numbers, whether human‐induced or caused by natural factors, may offer windows of opportunity for regeneration of a range of tree species and facilitate more diverse and dynamic forest development.     

Anticonvulsant evaluation of aminoalkanol derivatives of 2- and 4-methylxanthone

A series of 17 new aminoalkanol derivatives of 6-methoxy- or 7-chloro-2-methylxanthone as well as 6-methoxy-4-methylxanthone was synthesized and evaluated for anticonvulsant activity. All compounds were verified in mice after intraperitoneal (ip) administration in maximal electroshock (MES) and subcutaneous pentetrazole (scMet) induced seizures as well as neurotoxicity assessment. Eleven of the tested substances showed protection against electrically evoked seizures in the majority of the tested mice at the dose of 100 mg/kg. Additionally, one was effective at the dose of 30 mg/kg. Five substances were active at the dose of 300 mg/kg or at the dose of 100 mg/kg in the minority of the tested mice. The most promising compound revealed ED₅₀ value of 47.57 mg/kg in MES (mice, ip, 1 h after administration) and at the same time its TD₅₀ was evaluated as above 400 mg/kg. Those values gave PI (calculated as TD₅₀/ED₅₀) of more than 8.41. Three other synthesized xanthone derivatives also proved to act as anticonvulsants and showed ED₅₀ values in MES test (mice, ip) ranged 80–110 mg/kg. Results were quite encouraging and suggested that in the group of xanthone derivatives new potential anticonvulsants might be found.