Land snail diversity and composition in relation to ecological variations in Central European floodplain forests and their history

We explored patterns of land snail assemblages using 93 alluvial forest sites in six river floodplains of the Elbe drainage basin (northwestern Bohemia, Czech Republic). Differences in species richness and composition across the four floodplain forest types (i.e., alder carrs, ash-alder forests, willow-poplar softwood forests, and hardwood forests) were analysed using generalized linear models, multidimensional scaling and redundancy analysis with the Monte Carlo permutation test. The studied floodplain forest types did not differ in species richness, except for the alder carrs which were significantly poorer. The number of species expressed a significant unimodal response along with elevation and Ellenberg nutrients, and further significantly decreased towards the most humid sites. Contrary to species richness, the main forest types clearly differed based on land snail species composition, with the exception of the ash-alder and willow-poplar forest sites which became completely overlapped in the ordination space. The main changes in species composition were mostly associated with elevation and Ellenberg moisture on the first MDS axis: Ellenberg nutrients and light were fitted on the second and the third axes, respectively. These variables, along with calcium content estimated using Ellenberg indicator values for soil reaction, had significant effects on the variation and snail species composition in the final RDA model. No response of either species richness or compositional changes was found for the measured content of topsoil calcium, most likely due to the higher importance of other variables. On the basis of some recently published data we can conclude that historical development and long-term human activities on the succession of floodplain assemblages have resulted in a sharp impoverishment of strictly land snail species of several hardwood forest sites in the majority of lower river stretches. Whilst in most areas there are no exact palaeoecological data available, these historical influences were closely correlated with the site elevation in our dataset as the main difference in species composition was hard to explain solely using environmental predictors

Micro finite element analysis of dental implants under different loading conditions

Osseointegration is paramount for the longevity of dental implants and is significantly influenced by biomechanical stimuli. The aim of the present study was to assess the micro-strain and displacement induced by loaded dental implants at different stages of osseointegration using finite element analysis (FEA). Computational models of two mandible segments with different trabecular densities were constructed using microCT data. Three different implant loading directions and two osseointegration stages were considered in the stress-strain analysis of the bone-implant assembly. The bony segments were analyzed using two approaches. The first approach was based on Mechanostat strain intervals and the second approach was based on tensile/compression yield strains. The results of this study revealed that bone surrounding dental implants is critically strained in cases when only a partial osseointegration is present and when an implant is loaded by buccolingual forces. In such cases, implants also encounter high stresses. Displacements of partially-osseointegrated implant are significantly larger than those of fully-osseointegrated implants. It can be concluded that the partial osseointegration is a potential risk in terms of implant longevity

Životní spokojenost přeživších holocaust

Objective: Find out the impact of the Holocaust trauma on life satisfaction of alive Czech survivors, and to compare it with a control group of respondents. Design: Prospective study Participants: The total number of respondents in the study was 130. The exposed group consisted of 65 Czech Holocaust survivors (average age 88.5 years), control group of 65 Czech seniors (average age 88 years). Methods: The article presents a quantitative research assessing the life satisfaction of survivors using the standardized Life Satisfaction Questionnaire by Fahrenberg et al. (1986) on a main group, and compares it with a control group. A non-parametric test for two selections (Mann - Whitney) at a significance level of 0.05 was used to test the hypotheses. Results: In spite of wide spectrum of the Holocaust effects, the exposed group shows higher or the same satisfactionin the most of the monitored areas compared to the control group (Health Me 4 vs. 3, p - 0.000; Workand employment Me 6 vs. 5, p - 0.000; Financial situation Me 6 vs. 4, p - 0.000; Leisure time Me 4 vs. 4, p - 0.002; Marriage and partnership Me 2 vs. 0, p - 0.284; Own self Me 4 vs. 3, p - 0.000; Sexuality Me 3 vs. 3, p - 0.879; Friends and acquaintances Me 5 vs. 4, p - 0.002; Housing Me 5 vs. 4, p - 0.000; Overall life satisfaction Me 5 vs. 4, p - 0.001). On the contrary, they are less satisfied in the area Children (Me 4 vs. 5, p - 0.016). Conclusions: The research displays integration of hardiness and vulnerability, lust for life and the ability of man to live and survive in extreme conditions and still feel a joy of life.íl: Zjistit dopad traumatu holocaustu na životní spokojenost žijících českých přeživších a porovnat jej s kontrolní skupinou respondentů. Design: Prospektivní studie Účastníci: Celkový počet respondentů ve studii byl 130. Exponovanou skupinu tvořilo 65 českých přeživších holocaustu (průměrný věk 88,5 let), kontrolní skupinu 65 českých seniorů (průměrný věk 88 let). Metody: Článek představuje kvantitativní výzkum hodnotící životní spokojenost přeživších pomocí standardizovaného dotazníku Life Satisfaction Questionnaire od Fahrenberga et al. (1986) na hlavní skupině a srovnává ji s kontrolní skupinou. K testování hypotéz byl použit neparametrický test pro dva výběry (Mann - Whitney) na hladině významnosti 0,05. Výsledky: I přes široké spektrum účinků holocaustu vykazuje exponovaná skupina ve většině sledovaných oblastí vyšší nebo stejnou spokojenost ve srovnání s kontrolní skupinou (Zdraví Me 4 vs. 3, p - 0,000; Práce a zaměstnání Me 6 vs. 5, p - 0,000; Finanční situace Já 6 vs. 4, p - 0,000; Volný čas Já 4 vs. 4, p - 0,002; Manželství a partnerství Já 2 vs. 0, p - 0,284; Vlastní já Já 4 vs. 3 , p - 0,000; Sexualita já 3 vs. 3, p - 0,879; přátelé a známí já 5 vs. 4, p - 0,002; Bydlení já 5 vs. 4, p - 0,000; Celková životní spokojenost já 5 vs. 4, p - 0,001). Naopak méně spokojeni jsou v oblasti Děti (Já 4 vs. 5, p - 0,016). Závěry: Výzkum ukazuje integraci odolnosti a zranitelnosti, chuti do života a schopnosti člověka žít a přežít v extrémních podmínkách a přitom pociťovat radost ze život